16 files changed, 4866 insertions, 0 deletions

diff --git a/Documentation/filesystems/caching/cachefiles.txt b/Documentation/filesystems/caching/cachefiles.txt
new file mode 100644
index 000000000000..c78a49b7bba6
--- /dev/null
+++ b/Documentation/filesystems/caching/cachefiles.txt
@@ -0,0 +1,501 @@
+               ===============================================
+               CacheFiles: CACHE ON ALREADY MOUNTED FILESYSTEM
+               ===============================================
+
+Contents:
+
+ (*) Overview.
+
+ (*) Requirements.
+
+ (*) Configuration.
+
+ (*) Starting the cache.
+
+ (*) Things to avoid.
+
+ (*) Cache culling.
+
+ (*) Cache structure.
+
+ (*) Security model and SELinux.
+
+ (*) A note on security.
+
+ (*) Statistical information.
+
+ (*) Debugging.
+
+
+========
+OVERVIEW
+========
+
+CacheFiles is a caching backend that's meant to use as a cache a directory on
+an already mounted filesystem of a local type (such as Ext3).
+
+CacheFiles uses a userspace daemon to do some of the cache management - such as
+reaping stale nodes and culling.  This is called cachefilesd and lives in
+/sbin.
+
+The filesystem and data integrity of the cache are only as good as those of the
+filesystem providing the backing services.  Note that CacheFiles does not
+attempt to journal anything since the journalling interfaces of the various
+filesystems are very specific in nature.
+
+CacheFiles creates a misc character device - "/dev/cachefiles" - that is used
+to communication with the daemon.  Only one thing may have this open at once,
+and whilst it is open, a cache is at least partially in existence.  The daemon
+opens this and sends commands down it to control the cache.
+
+CacheFiles is currently limited to a single cache.
+
+CacheFiles attempts to maintain at least a certain percentage of free space on
+the filesystem, shrinking the cache by culling the objects it contains to make
+space if necessary - see the "Cache Culling" section.  This means it can be
+placed on the same medium as a live set of data, and will expand to make use of
+spare space and automatically contract when the set of data requires more
+space.
+
+
+============
+REQUIREMENTS
+============
+
+The use of CacheFiles and its daemon requires the following features to be
+available in the system and in the cache filesystem:
+
+        - dnotify.
+
+        - extended attributes (xattrs).
+
+        - openat() and friends.
+
+        - bmap() support on files in the filesystem (FIBMAP ioctl).
+
+        - The use of bmap() to detect a partial page at the end of the file.
+
+It is strongly recommended that the "dir_index" option is enabled on Ext3
+filesystems being used as a cache.
+
+
+=============
+CONFIGURATION
+=============
+
+The cache is configured by a script in /etc/cachefilesd.conf.  These commands
+set up cache ready for use.  The following script commands are available:
+
+ (*) brun <N>%
+ (*) bcull <N>%
+ (*) bstop <N>%
+ (*) frun <N>%
+ (*) fcull <N>%
+ (*) fstop <N>%
+
+        Configure the culling limits.  Optional.  See the section on culling
+        The defaults are 7% (run), 5% (cull) and 1% (stop) respectively.
+
+        The commands beginning with a 'b' are file space (block) limits, those
+        beginning with an 'f' are file count limits.
+
+ (*) dir <path>
+
+        Specify the directory containing the root of the cache.  Mandatory.
+
+ (*) tag <name>
+
+        Specify a tag to FS-Cache to use in distinguishing multiple caches.
+        Optional.  The default is "CacheFiles".
+
+ (*) debug <mask>
+
+        Specify a numeric bitmask to control debugging in the kernel module.
+        Optional.  The default is zero (all off).  The following values can be
+        OR'd into the mask to collect various information:
+
+                1       Turn on trace of function entry (_enter() macros)
+                2       Turn on trace of function exit (_leave() macros)
+                4       Turn on trace of internal debug points (_debug())
+
+        This mask can also be set through sysfs, eg:
+
+                echo 5 >/sys/modules/cachefiles/parameters/debug
+
+
+==================
+STARTING THE CACHE
+==================
+
+The cache is started by running the daemon.  The daemon opens the cache device,
+configures the cache and tells it to begin caching.  At that point the cache
+binds to fscache and the cache becomes live.
+
+The daemon is run as follows:
+
+        /sbin/cachefilesd [-d]* [-s] [-n] [-f <configfile>]
+
+The flags are:
+
+ (*) -d
+
+        Increase the debugging level.  This can be specified multiple times and
+        is cumulative with itself.
+
+ (*) -s
+
+        Send messages to stderr instead of syslog.
+
+ (*) -n
+
+        Don't daemonise and go into background.
+
+ (*) -f <configfile>
+
+        Use an alternative configuration file rather than the default one.
+
+
+===============
+THINGS TO AVOID
+===============
+
+Do not mount other things within the cache as this will cause problems.  The
+kernel module contains its own very cut-down path walking facility that ignores
+mountpoints, but the daemon can't avoid them.
+
+Do not create, rename or unlink files and directories in the cache whilst the
+cache is active, as this may cause the state to become uncertain.
+
+Renaming files in the cache might make objects appear to be other objects (the
+filename is part of the lookup key).
+
+Do not change or remove the extended attributes attached to cache files by the
+cache as this will cause the cache state management to get confused.
+
+Do not create files or directories in the cache, lest the cache get confused or
+serve incorrect data.
+
+Do not chmod files in the cache.  The module creates things with minimal
+permissions to prevent random users being able to access them directly.
+
+
+=============
+CACHE CULLING
+=============
+
+The cache may need culling occasionally to make space.  This involves
+discarding objects from the cache that have been used less recently than
+anything else.  Culling is based on the access time of data objects.  Empty
+directories are culled if not in use.
+
+Cache culling is done on the basis of the percentage of blocks and the
+percentage of files available in the underlying filesystem.  There are six
+"limits":
+
+ (*) brun
+ (*) frun
+
+     If the amount of free space and the number of available files in the cache
+     rises above both these limits, then culling is turned off.
+
+ (*) bcull
+ (*) fcull
+
+     If the amount of available space or the number of available files in the
+     cache falls below either of these limits, then culling is started.
+
+ (*) bstop
+ (*) fstop
+
+     If the amount of available space or the number of available files in the
+     cache falls below either of these limits, then no further allocation of
+     disk space or files is permitted until culling has raised things above
+     these limits again.
+
+These must be configured thusly:
+
+        0 <= bstop < bcull < brun < 100
+        0 <= fstop < fcull < frun < 100
+
+Note that these are percentages of available space and available files, and do
+_not_ appear as 100 minus the percentage displayed by the "df" program.
+
+The userspace daemon scans the cache to build up a table of cullable objects.
+These are then culled in least recently used order.  A new scan of the cache is
+started as soon as space is made in the table.  Objects will be skipped if
+their atimes have changed or if the kernel module says it is still using them.
+
+
+===============
+CACHE STRUCTURE
+===============
+
+The CacheFiles module will create two directories in the directory it was
+given:
+
+ (*) cache/
+
+ (*) graveyard/
+
+The active cache objects all reside in the first directory.  The CacheFiles
+kernel module moves any retired or culled objects that it can't simply unlink
+to the graveyard from which the daemon will actually delete them.
+
+The daemon uses dnotify to monitor the graveyard directory, and will delete
+anything that appears therein.
+
+
+The module represents index objects as directories with the filename "I..." or
+"J...".  Note that the "cache/" directory is itself a special index.
+
+Data objects are represented as files if they have no children, or directories
+if they do.  Their filenames all begin "D..." or "E...".  If represented as a
+directory, data objects will have a file in the directory called "data" that
+actually holds the data.
+
+Special objects are similar to data objects, except their filenames begin
+"S..." or "T...".
+
+
+If an object has children, then it will be represented as a directory.
+Immediately in the representative directory are a collection of directories
+named for hash values of the child object keys with an '@' prepended.  Into
+this directory, if possible, will be placed the representations of the child
+objects:
+
+        INDEX     INDEX      INDEX                             DATA FILES
+        ========= ========== ================================= ================
+        cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400
+        cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...DB1ry
+        cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...N22ry
+        cache/@4a/I03nfs/@30/Ji000000000000000--fHg8hi8400/@75/Es0g000w...FP1ry
+
+
+If the key is so long that it exceeds NAME_MAX with the decorations added on to
+it, then it will be cut into pieces, the first few of which will be used to
+make a nest of directories, and the last one of which will be the objects
+inside the last directory.  The names of the intermediate directories will have
+'+' prepended:
+
+        J1223/@23/+xy...z/+kl...m/Epqr
+
+
+Note that keys are raw data, and not only may they exceed NAME_MAX in size,
+they may also contain things like '/' and NUL characters, and so they may not
+be suitable for turning directly into a filename.
+
+To handle this, CacheFiles will use a suitably printable filename directly and
+"base-64" encode ones that aren't directly suitable.  The two versions of
+object filenames indicate the encoding:
+
+        OBJECT TYPE     PRINTABLE       ENCODED
+        =============== =============== ===============
+        Index           "I..."          "J..."
+        Data            "D..."          "E..."
+        Special         "S..."          "T..."
+
+Intermediate directories are always "@" or "+" as appropriate.
+
+
+Each object in the cache has an extended attribute label that holds the object
+type ID (required to distinguish special objects) and the auxiliary data from
+the netfs.  The latter is used to detect stale objects in the cache and update
+or retire them.
+
+
+Note that CacheFiles will erase from the cache any file it doesn't recognise or
+any file of an incorrect type (such as a FIFO file or a device file).
+
+
+==========================
+SECURITY MODEL AND SELINUX
+==========================
+
+CacheFiles is implemented to deal properly with the LSM security features of
+the Linux kernel and the SELinux facility.
+
+One of the problems that CacheFiles faces is that it is generally acting on
+behalf of a process, and running in that process's context, and that includes a
+security context that is not appropriate for accessing the cache - either
+because the files in the cache are inaccessible to that process, or because if
+the process creates a file in the cache, that file may be inaccessible to other
+processes.
+
+The way CacheFiles works is to temporarily change the security context (fsuid,
+fsgid and actor security label) that the process acts as - without changing the
+security context of the process when it the target of an operation performed by
+some other process (so signalling and suchlike still work correctly).
+
+
+When the CacheFiles module is asked to bind to its cache, it:
+
+ (1) Finds the security label attached to the root cache directory and uses
+     that as the security label with which it will create files.  By default,
+     this is:
+
+        cachefiles_var_t
+
+ (2) Finds the security label of the process which issued the bind request
+     (presumed to be the cachefilesd daemon), which by default will be:
+
+        cachefilesd_t
+
+     and asks LSM to supply a security ID as which it should act given the
+     daemon's label.  By default, this will be:
+
+        cachefiles_kernel_t
+
+     SELinux transitions the daemon's security ID to the module's security ID
+     based on a rule of this form in the policy.
+
+        type_transition <daemon's-ID> kernel_t : process <module's-ID>;
+
+     For instance:
+
+        type_transition cachefilesd_t kernel_t : process cachefiles_kernel_t;
+
+
+The module's security ID gives it permission to create, move and remove files
+and directories in the cache, to find and access directories and files in the
+cache, to set and access extended attributes on cache objects, and to read and
+write files in the cache.
+
+The daemon's security ID gives it only a very restricted set of permissions: it
+may scan directories, stat files and erase files and directories.  It may
+not read or write files in the cache, and so it is precluded from accessing the
+data cached therein; nor is it permitted to create new files in the cache.
+
+
+There are policy source files available in:
+
+        http://people.redhat.com/~dhowells/fscache/cachefilesd-0.8.tar.bz2
+
+and later versions.  In that tarball, see the files:
+
+        cachefilesd.te
+        cachefilesd.fc
+        cachefilesd.if
+
+They are built and installed directly by the RPM.
+
+If a non-RPM based system is being used, then copy the above files to their own
+directory and run:
+
+        make -f /usr/share/selinux/devel/Makefile
+        semodule -i cachefilesd.pp
+
+You will need checkpolicy and selinux-policy-devel installed prior to the
+build.
+
+
+By default, the cache is located in /var/fscache, but if it is desirable that
+it should be elsewhere, than either the above policy files must be altered, or
+an auxiliary policy must be installed to label the alternate location of the
+cache.
+
+For instructions on how to add an auxiliary policy to enable the cache to be
+located elsewhere when SELinux is in enforcing mode, please see:
+
+        /usr/share/doc/cachefilesd-*/move-cache.txt
+
+When the cachefilesd rpm is installed; alternatively, the document can be found
+in the sources.
+
+
+==================
+A NOTE ON SECURITY
+==================
+
+CacheFiles makes use of the split security in the task_struct.  It allocates
+its own task_security structure, and redirects current->act_as to point to it
+when it acts on behalf of another process, in that process's context.
+
+The reason it does this is that it calls vfs_mkdir() and suchlike rather than
+bypassing security and calling inode ops directly.  Therefore the VFS and LSM
+may deny the CacheFiles access to the cache data because under some
+circumstances the caching code is running in the security context of whatever
+process issued the original syscall on the netfs.
+
+Furthermore, should CacheFiles create a file or directory, the security
+parameters with that object is created (UID, GID, security label) would be
+derived from that process that issued the system call, thus potentially
+preventing other processes from accessing the cache - including CacheFiles's
+cache management daemon (cachefilesd).
+
+What is required is to temporarily override the security of the process that
+issued the system call.  We can't, however, just do an in-place change of the
+security data as that affects the process as an object, not just as a subject.
+This means it may lose signals or ptrace events for example, and affects what
+the process looks like in /proc.
+
+So CacheFiles makes use of a logical split in the security between the
+objective security (task->sec) and the subjective security (task->act_as).  The
+objective security holds the intrinsic security properties of a process and is
+never overridden.  This is what appears in /proc, and is what is used when a
+process is the target of an operation by some other process (SIGKILL for
+example).
+
+The subjective security holds the active security properties of a process, and
+may be overridden.  This is not seen externally, and is used whan a process
+acts upon another object, for example SIGKILLing another process or opening a
+file.
+
+LSM hooks exist that allow SELinux (or Smack or whatever) to reject a request
+for CacheFiles to run in a context of a specific security label, or to create
+files and directories with another security label.
+
+
+=======================
+STATISTICAL INFORMATION
+=======================
+
+If FS-Cache is compiled with the following option enabled:
+
+        CONFIG_CACHEFILES_HISTOGRAM=y
+
+then it will gather certain statistics and display them through a proc file.
+
+ (*) /proc/fs/cachefiles/histogram
+
+        cat /proc/fs/cachefiles/histogram
+        JIFS  SECS  LOOKUPS   MKDIRS    CREATES
+        ===== ===== ========= ========= =========
+
+     This shows the breakdown of the number of times each amount of time
+     between 0 jiffies and HZ-1 jiffies a variety of tasks took to run.  The
+     columns are as follows:
+
+        COLUMN          TIME MEASUREMENT
+        =======         =======================================================
+        LOOKUPS         Length of time to perform a lookup on the backing fs
+        MKDIRS          Length of time to perform a mkdir on the backing fs
+        CREATES         Length of time to perform a create on the backing fs
+
+     Each row shows the number of events that took a particular range of times.
+     Each step is 1 jiffy in size.  The JIFS column indicates the particular
+     jiffy range covered, and the SECS field the equivalent number of seconds.
+
+
+=========
+DEBUGGING
+=========
+
+If CONFIG_CACHEFILES_DEBUG is enabled, the CacheFiles facility can have runtime
+debugging enabled by adjusting the value in:
+
+        /sys/module/cachefiles/parameters/debug
+
+This is a bitmask of debugging streams to enable:
+
+        BIT     VALUE   STREAM                          POINT
+        ======= ======= =============================== =======================
+        0       1       General                         Function entry trace
+        1       2                                       Function exit trace
+        2       4                                       General
+
+The appropriate set of values should be OR'd together and the result written to
+the control file.  For example:
+
+        echo $((1|4|8)) >/sys/module/cachefiles/parameters/debug
+
+will turn on all function entry debugging.
diff --git a/fs/Kconfig b/fs/Kconfig
index 3942df6ad04f..c0022b1d5877 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -69,6 +69,7 @@ config GENERIC_ACL
 menu "Caches"
 
 source "fs/fscache/Kconfig"
+source "fs/cachefiles/Kconfig"
 
 endmenu
 
diff --git a/fs/Makefile b/fs/Makefile
index ff5a10d898c6..055d5237b109 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -117,6 +117,7 @@ obj-$(CONFIG_AFS_FS)		+= afs/
 obj-$(CONFIG_BEFS_FS)           += befs/
 obj-$(CONFIG_HOSTFS)            += hostfs/
 obj-$(CONFIG_HPPFS)             += hppfs/
+obj-$(CONFIG_CACHEFILES)        += cachefiles/
 obj-$(CONFIG_DEBUG_FS)          += debugfs/
 obj-$(CONFIG_OCFS2_FS)          += ocfs2/
 obj-$(CONFIG_BTRFS_FS)          += btrfs/
diff --git a/fs/cachefiles/Kconfig b/fs/cachefiles/Kconfig
new file mode 100644
index 000000000000..80e9c6167f0b
--- /dev/null
+++ b/fs/cachefiles/Kconfig
@@ -0,0 +1,39 @@
+
+config CACHEFILES
+        tristate "Filesystem caching on files"
+        depends on FSCACHE && BLOCK
+        help
+          This permits use of a mounted filesystem as a cache for other
+          filesystems - primarily networking filesystems - thus allowing fast
+          local disk to enhance the speed of slower devices.
+
+          See Documentation/filesystems/caching/cachefiles.txt for more
+          information.
+
+config CACHEFILES_DEBUG
+        bool "Debug CacheFiles"
+        depends on CACHEFILES
+        help
+          This permits debugging to be dynamically enabled in the filesystem
+          caching on files module.  If this is set, the debugging output may be
+          enabled by setting bits in /sys/modules/cachefiles/parameter/debug or
+          by including a debugging specifier in /etc/cachefilesd.conf.
+
+config CACHEFILES_HISTOGRAM
+        bool "Gather latency information on CacheFiles"
+        depends on CACHEFILES && PROC_FS
+        help
+
+          This option causes latency information to be gathered on CacheFiles
+          operation and exported through file:
+
+                /proc/fs/cachefiles/histogram
+
+          The generation of this histogram adds a certain amount of overhead to
+          execution as there are a number of points at which data is gathered,
+          and on a multi-CPU system these may be on cachelines that keep
+          bouncing between CPUs.  On the other hand, the histogram may be
+          useful for debugging purposes.  Saying 'N' here is recommended.
+
+          See Documentation/filesystems/caching/cachefiles.txt for more
+          information.
diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile
new file mode 100644
index 000000000000..32cbab0ffce3
--- /dev/null
+++ b/fs/cachefiles/Makefile
@@ -0,0 +1,18 @@
+#
+# Makefile for caching in a mounted filesystem
+#
+
+cachefiles-y := \
+        bind.o \
+        daemon.o \
+        interface.o \
+        key.o \
+        main.o \
+        namei.o \
+        rdwr.o \
+        security.o \
+        xattr.o
+
+cachefiles-$(CONFIG_CACHEFILES_HISTOGRAM) += proc.o
+
+obj-$(CONFIG_CACHEFILES) := cachefiles.o
diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c
new file mode 100644
index 000000000000..3797e0077b35
--- /dev/null
+++ b/fs/cachefiles/bind.c
@@ -0,0 +1,286 @@
+/* Bind and unbind a cache from the filesystem backing it
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/ctype.h>
+#include "internal.h"
+
+static int cachefiles_daemon_add_cache(struct cachefiles_cache *caches);
+
+/*
+ * bind a directory as a cache
+ */
+int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
+{
+        _enter("{%u,%u,%u,%u,%u,%u},%s",
+               cache->frun_percent,
+               cache->fcull_percent,
+               cache->fstop_percent,
+               cache->brun_percent,
+               cache->bcull_percent,
+               cache->bstop_percent,
+               args);
+
+        /* start by checking things over */
+        ASSERT(cache->fstop_percent >= 0 &&
+               cache->fstop_percent < cache->fcull_percent &&
+               cache->fcull_percent < cache->frun_percent &&
+               cache->frun_percent  < 100);
+
+        ASSERT(cache->bstop_percent >= 0 &&
+               cache->bstop_percent < cache->bcull_percent &&
+               cache->bcull_percent < cache->brun_percent &&
+               cache->brun_percent  < 100);
+
+        if (*args) {
+                kerror("'bind' command doesn't take an argument");
+                return -EINVAL;
+        }
+
+        if (!cache->rootdirname) {
+                kerror("No cache directory specified");
+                return -EINVAL;
+        }
+
+        /* don't permit already bound caches to be re-bound */
+        if (test_bit(CACHEFILES_READY, &cache->flags)) {
+                kerror("Cache already bound");
+                return -EBUSY;
+        }
+
+        /* make sure we have copies of the tag and dirname strings */
+        if (!cache->tag) {
+                /* the tag string is released by the fops->release()
+                 * function, so we don't release it on error here */
+                cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
+                if (!cache->tag)
+                        return -ENOMEM;
+        }
+
+        /* add the cache */
+        return cachefiles_daemon_add_cache(cache);
+}
+
+/*
+ * add a cache
+ */
+static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache)
+{
+        struct cachefiles_object *fsdef;
+        struct nameidata nd;
+        struct kstatfs stats;
+        struct dentry *graveyard, *cachedir, *root;
+        const struct cred *saved_cred;
+        int ret;
+
+        _enter("");
+
+        /* we want to work under the module's security ID */
+        ret = cachefiles_get_security_ID(cache);
+        if (ret < 0)
+                return ret;
+
+        cachefiles_begin_secure(cache, &saved_cred);
+
+        /* allocate the root index object */
+        ret = -ENOMEM;
+
+        fsdef = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
+        if (!fsdef)
+                goto error_root_object;
+
+        ASSERTCMP(fsdef->backer, ==, NULL);
+
+        atomic_set(&fsdef->usage, 1);
+        fsdef->type = FSCACHE_COOKIE_TYPE_INDEX;
+
+        _debug("- fsdef %p", fsdef);
+
+        /* look up the directory at the root of the cache */
+        memset(&nd, 0, sizeof(nd));
+
+        ret = path_lookup(cache->rootdirname, LOOKUP_DIRECTORY, &nd);
+        if (ret < 0)
+                goto error_open_root;
+
+        cache->mnt = mntget(nd.path.mnt);
+        root = dget(nd.path.dentry);
+        path_put(&nd.path);
+
+        /* check parameters */
+        ret = -EOPNOTSUPP;
+        if (!root->d_inode ||
+            !root->d_inode->i_op ||
+            !root->d_inode->i_op->lookup ||
+            !root->d_inode->i_op->mkdir ||
+            !root->d_inode->i_op->setxattr ||
+            !root->d_inode->i_op->getxattr ||
+            !root->d_sb ||
+            !root->d_sb->s_op ||
+            !root->d_sb->s_op->statfs ||
+            !root->d_sb->s_op->sync_fs)
+                goto error_unsupported;
+
+        ret = -EROFS;
+        if (root->d_sb->s_flags & MS_RDONLY)
+                goto error_unsupported;
+
+        /* determine the security of the on-disk cache as this governs
+         * security ID of files we create */
+        ret = cachefiles_determine_cache_security(cache, root, &saved_cred);
+        if (ret < 0)
+                goto error_unsupported;
+
+        /* get the cache size and blocksize */
+        ret = vfs_statfs(root, &stats);
+        if (ret < 0)
+                goto error_unsupported;
+
+        ret = -ERANGE;
+        if (stats.f_bsize <= 0)
+                goto error_unsupported;
+
+        ret = -EOPNOTSUPP;
+        if (stats.f_bsize > PAGE_SIZE)
+                goto error_unsupported;
+
+        cache->bsize = stats.f_bsize;
+        cache->bshift = 0;
+        if (stats.f_bsize < PAGE_SIZE)
+                cache->bshift = PAGE_SHIFT - ilog2(stats.f_bsize);
+
+        _debug("blksize %u (shift %u)",
+               cache->bsize, cache->bshift);
+
+        _debug("size %llu, avail %llu",
+               (unsigned long long) stats.f_blocks,
+               (unsigned long long) stats.f_bavail);
+
+        /* set up caching limits */
+        do_div(stats.f_files, 100);
+        cache->fstop = stats.f_files * cache->fstop_percent;
+        cache->fcull = stats.f_files * cache->fcull_percent;
+        cache->frun  = stats.f_files * cache->frun_percent;
+
+        _debug("limits {%llu,%llu,%llu} files",
+               (unsigned long long) cache->frun,
+               (unsigned long long) cache->fcull,
+               (unsigned long long) cache->fstop);
+
+        stats.f_blocks >>= cache->bshift;
+        do_div(stats.f_blocks, 100);
+        cache->bstop = stats.f_blocks * cache->bstop_percent;
+        cache->bcull = stats.f_blocks * cache->bcull_percent;
+        cache->brun  = stats.f_blocks * cache->brun_percent;
+
+        _debug("limits {%llu,%llu,%llu} blocks",
+               (unsigned long long) cache->brun,
+               (unsigned long long) cache->bcull,
+               (unsigned long long) cache->bstop);
+
+        /* get the cache directory and check its type */
+        cachedir = cachefiles_get_directory(cache, root, "cache");
+        if (IS_ERR(cachedir)) {
+                ret = PTR_ERR(cachedir);
+                goto error_unsupported;
+        }
+
+        fsdef->dentry = cachedir;
+        fsdef->fscache.cookie = NULL;
+
+        ret = cachefiles_check_object_type(fsdef);
+        if (ret < 0)
+                goto error_unsupported;
+
+        /* get the graveyard directory */
+        graveyard = cachefiles_get_directory(cache, root, "graveyard");
+        if (IS_ERR(graveyard)) {
+                ret = PTR_ERR(graveyard);
+                goto error_unsupported;
+        }
+
+        cache->graveyard = graveyard;
+
+        /* publish the cache */
+        fscache_init_cache(&cache->cache,
+                           &cachefiles_cache_ops,
+                           "%s",
+                           fsdef->dentry->d_sb->s_id);
+
+        fscache_object_init(&fsdef->fscache, NULL, &cache->cache);
+
+        ret = fscache_add_cache(&cache->cache, &fsdef->fscache, cache->tag);
+        if (ret < 0)
+                goto error_add_cache;
+
+        /* done */
+        set_bit(CACHEFILES_READY, &cache->flags);
+        dput(root);
+
+        printk(KERN_INFO "CacheFiles:"
+               " File cache on %s registered\n",
+               cache->cache.identifier);
+
+        /* check how much space the cache has */
+        cachefiles_has_space(cache, 0, 0);
+        cachefiles_end_secure(cache, saved_cred);
+        return 0;
+
+error_add_cache:
+        dput(cache->graveyard);
+        cache->graveyard = NULL;
+error_unsupported:
+        mntput(cache->mnt);
+        cache->mnt = NULL;
+        dput(fsdef->dentry);
+        fsdef->dentry = NULL;
+        dput(root);
+error_open_root:
+        kmem_cache_free(cachefiles_object_jar, fsdef);
+error_root_object:
+        cachefiles_end_secure(cache, saved_cred);
+        kerror("Failed to register: %d", ret);
+        return ret;
+}
+
+/*
+ * unbind a cache on fd release
+ */
+void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
+{
+        _enter("");
+
+        if (test_bit(CACHEFILES_READY, &cache->flags)) {
+                printk(KERN_INFO "CacheFiles:"
+                       " File cache on %s unregistering\n",
+                       cache->cache.identifier);
+
+                fscache_withdraw_cache(&cache->cache);
+        }
+
+        dput(cache->graveyard);
+        mntput(cache->mnt);
+
+        kfree(cache->rootdirname);
+        kfree(cache->secctx);
+        kfree(cache->tag);
+
+        _leave("");
+}
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
new file mode 100644
index 000000000000..4618516dd994
--- /dev/null
+++ b/fs/cachefiles/daemon.c
@@ -0,0 +1,755 @@
+/* Daemon interface
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/ctype.h>
+#include <linux/fs_struct.h>
+#include "internal.h"
+
+static int cachefiles_daemon_open(struct inode *, struct file *);
+static int cachefiles_daemon_release(struct inode *, struct file *);
+static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
+                                      loff_t *);
+static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
+                                       size_t, loff_t *);
+static unsigned int cachefiles_daemon_poll(struct file *,
+                                           struct poll_table_struct *);
+static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
+static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
+
+static unsigned long cachefiles_open;
+
+const struct file_operations cachefiles_daemon_fops = {
+        .owner          = THIS_MODULE,
+        .open           = cachefiles_daemon_open,
+        .release        = cachefiles_daemon_release,
+        .read           = cachefiles_daemon_read,
+        .write          = cachefiles_daemon_write,
+        .poll           = cachefiles_daemon_poll,
+};
+
+struct cachefiles_daemon_cmd {
+        char name[8];
+        int (*handler)(struct cachefiles_cache *cache, char *args);
+};
+
+static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
+        { "bind",       cachefiles_daemon_bind          },
+        { "brun",       cachefiles_daemon_brun          },
+        { "bcull",      cachefiles_daemon_bcull         },
+        { "bstop",      cachefiles_daemon_bstop         },
+        { "cull",       cachefiles_daemon_cull          },
+        { "debug",      cachefiles_daemon_debug         },
+        { "dir",        cachefiles_daemon_dir           },
+        { "frun",       cachefiles_daemon_frun          },
+        { "fcull",      cachefiles_daemon_fcull         },
+        { "fstop",      cachefiles_daemon_fstop         },
+        { "inuse",      cachefiles_daemon_inuse         },
+        { "secctx",     cachefiles_daemon_secctx        },
+        { "tag",        cachefiles_daemon_tag           },
+        { "",           NULL                            }
+};
+
+
+/*
+ * do various checks
+ */
+static int cachefiles_daemon_open(struct inode *inode, struct file *file)
+{
+        struct cachefiles_cache *cache;
+
+        _enter("");
+
+        /* only the superuser may do this */
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        /* the cachefiles device may only be open once at a time */
+        if (xchg(&cachefiles_open, 1) == 1)
+                return -EBUSY;
+
+        /* allocate a cache record */
+        cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
+        if (!cache) {
+                cachefiles_open = 0;
+                return -ENOMEM;
+        }
+
+        mutex_init(&cache->daemon_mutex);
+        cache->active_nodes = RB_ROOT;
+        rwlock_init(&cache->active_lock);
+        init_waitqueue_head(&cache->daemon_pollwq);
+
+        /* set default caching limits
+         * - limit at 1% free space and/or free files
+         * - cull below 5% free space and/or free files
+         * - cease culling above 7% free space and/or free files
+         */
+        cache->frun_percent = 7;
+        cache->fcull_percent = 5;
+        cache->fstop_percent = 1;
+        cache->brun_percent = 7;
+        cache->bcull_percent = 5;
+        cache->bstop_percent = 1;
+
+        file->private_data = cache;
+        cache->cachefilesd = file;
+        return 0;
+}
+
+/*
+ * release a cache
+ */
+static int cachefiles_daemon_release(struct inode *inode, struct file *file)
+{
+        struct cachefiles_cache *cache = file->private_data;
+
+        _enter("");
+
+        ASSERT(cache);
+
+        set_bit(CACHEFILES_DEAD, &cache->flags);
+
+        cachefiles_daemon_unbind(cache);
+
+        ASSERT(!cache->active_nodes.rb_node);
+
+        /* clean up the control file interface */
+        cache->cachefilesd = NULL;
+        file->private_data = NULL;
+        cachefiles_open = 0;
+
+        kfree(cache);
+
+        _leave("");
+        return 0;
+}
+
+/*
+ * read the cache state
+ */
+static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
+                                      size_t buflen, loff_t *pos)
+{
+        struct cachefiles_cache *cache = file->private_data;
+        char buffer[256];
+        int n;
+
+        //_enter(",,%zu,", buflen);
+
+        if (!test_bit(CACHEFILES_READY, &cache->flags))
+                return 0;
+
+        /* check how much space the cache has */
+        cachefiles_has_space(cache, 0, 0);
+
+        /* summarise */
+        clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
+
+        n = snprintf(buffer, sizeof(buffer),
+                     "cull=%c"
+                     " frun=%llx"
+                     " fcull=%llx"
+                     " fstop=%llx"
+                     " brun=%llx"
+                     " bcull=%llx"
+                     " bstop=%llx",
+                     test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
+                     (unsigned long long) cache->frun,
+                     (unsigned long long) cache->fcull,
+                     (unsigned long long) cache->fstop,
+                     (unsigned long long) cache->brun,
+                     (unsigned long long) cache->bcull,
+                     (unsigned long long) cache->bstop
+                     );
+
+        if (n > buflen)
+                return -EMSGSIZE;
+
+        if (copy_to_user(_buffer, buffer, n) != 0)
+                return -EFAULT;
+
+        return n;
+}
+
+/*
+ * command the cache
+ */
+static ssize_t cachefiles_daemon_write(struct file *file,
+                                       const char __user *_data,
+                                       size_t datalen,
+                                       loff_t *pos)
+{
+        const struct cachefiles_daemon_cmd *cmd;
+        struct cachefiles_cache *cache = file->private_data;
+        ssize_t ret;
+        char *data, *args, *cp;
+
+        //_enter(",,%zu,", datalen);
+
+        ASSERT(cache);
+
+        if (test_bit(CACHEFILES_DEAD, &cache->flags))
+                return -EIO;
+
+        if (datalen < 0 || datalen > PAGE_SIZE - 1)
+                return -EOPNOTSUPP;
+
+        /* drag the command string into the kernel so we can parse it */
+        data = kmalloc(datalen + 1, GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        ret = -EFAULT;
+        if (copy_from_user(data, _data, datalen) != 0)
+                goto error;
+
+        data[datalen] = '\0';
+
+        ret = -EINVAL;
+        if (memchr(data, '\0', datalen))
+                goto error;
+
+        /* strip any newline */
+        cp = memchr(data, '\n', datalen);
+        if (cp) {
+                if (cp == data)
+                        goto error;
+
+                *cp = '\0';
+        }
+
+        /* parse the command */
+        ret = -EOPNOTSUPP;
+
+        for (args = data; *args; args++)
+                if (isspace(*args))
+                        break;
+        if (*args) {
+                if (args == data)
+                        goto error;
+                *args = '\0';
+                for (args++; isspace(*args); args++)
+                        continue;
+        }
+
+        /* run the appropriate command handler */
+        for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
+                if (strcmp(cmd->name, data) == 0)
+                        goto found_command;
+
+error:
+        kfree(data);
+        //_leave(" = %zd", ret);
+        return ret;
+
+found_command:
+        mutex_lock(&cache->daemon_mutex);
+
+        ret = -EIO;
+        if (!test_bit(CACHEFILES_DEAD, &cache->flags))
+                ret = cmd->handler(cache, args);
+
+        mutex_unlock(&cache->daemon_mutex);
+
+        if (ret == 0)
+                ret = datalen;
+        goto error;
+}
+
+/*
+ * poll for culling state
+ * - use POLLOUT to indicate culling state
+ */
+static unsigned int cachefiles_daemon_poll(struct file *file,
+                                           struct poll_table_struct *poll)
+{
+        struct cachefiles_cache *cache = file->private_data;
+        unsigned int mask;
+
+        poll_wait(file, &cache->daemon_pollwq, poll);
+        mask = 0;
+
+        if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
+                mask |= POLLIN;
+
+        if (test_bit(CACHEFILES_CULLING, &cache->flags))
+                mask |= POLLOUT;
+
+        return mask;
+}
+
+/*
+ * give a range error for cache space constraints
+ * - can be tail-called
+ */
+static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
+                                         char *args)
+{
+        kerror("Free space limits must be in range"
+               " 0%%<=stop<cull<run<100%%");
+
+        return -EINVAL;
+}
+
+/*
+ * set the percentage of files at which to stop culling
+ * - command: "frun <N>%"
+ */
+static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long frun;
+
+        _enter(",%s", args);
+
+        if (!*args)
+                return -EINVAL;
+
+        frun = simple_strtoul(args, &args, 10);
+        if (args[0] != '%' || args[1] != '\0')
+                return -EINVAL;
+
+        if (frun <= cache->fcull_percent || frun >= 100)
+                return cachefiles_daemon_range_error(cache, args);
+
+        cache->frun_percent = frun;
+        return 0;
+}
+
+/*
+ * set the percentage of files at which to start culling
+ * - command: "fcull <N>%"
+ */
+static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long fcull;
+
+        _enter(",%s", args);
+
+        if (!*args)
+                return -EINVAL;
+
+        fcull = simple_strtoul(args, &args, 10);
+        if (args[0] != '%' || args[1] != '\0')
+                return -EINVAL;
+
+        if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
+                return cachefiles_daemon_range_error(cache, args);
+
+        cache->fcull_percent = fcull;
+        return 0;
+}
+
+/*
+ * set the percentage of files at which to stop allocating
+ * - command: "fstop <N>%"
+ */
+static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long fstop;
+
+        _enter(",%s", args);
+
+        if (!*args)
+                return -EINVAL;
+
+        fstop = simple_strtoul(args, &args, 10);
+        if (args[0] != '%' || args[1] != '\0')
+                return -EINVAL;
+
+        if (fstop < 0 || fstop >= cache->fcull_percent)
+                return cachefiles_daemon_range_error(cache, args);
+
+        cache->fstop_percent = fstop;
+        return 0;
+}
+
+/*
+ * set the percentage of blocks at which to stop culling
+ * - command: "brun <N>%"
+ */
+static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long brun;
+
+        _enter(",%s", args);
+
+        if (!*args)
+                return -EINVAL;
+
+        brun = simple_strtoul(args, &args, 10);
+        if (args[0] != '%' || args[1] != '\0')
+                return -EINVAL;
+
+        if (brun <= cache->bcull_percent || brun >= 100)
+                return cachefiles_daemon_range_error(cache, args);
+
+        cache->brun_percent = brun;
+        return 0;
+}
+
+/*
+ * set the percentage of blocks at which to start culling
+ * - command: "bcull <N>%"
+ */
+static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long bcull;
+
+        _enter(",%s", args);
+
+        if (!*args)
+                return -EINVAL;
+
+        bcull = simple_strtoul(args, &args, 10);
+        if (args[0] != '%' || args[1] != '\0')
+                return -EINVAL;
+
+        if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
+                return cachefiles_daemon_range_error(cache, args);
+
+        cache->bcull_percent = bcull;
+        return 0;
+}
+
+/*
+ * set the percentage of blocks at which to stop allocating
+ * - command: "bstop <N>%"
+ */
+static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long bstop;
+
+        _enter(",%s", args);
+
+        if (!*args)
+                return -EINVAL;
+
+        bstop = simple_strtoul(args, &args, 10);
+        if (args[0] != '%' || args[1] != '\0')
+                return -EINVAL;
+
+        if (bstop < 0 || bstop >= cache->bcull_percent)
+                return cachefiles_daemon_range_error(cache, args);
+
+        cache->bstop_percent = bstop;
+        return 0;
+}
+
+/*
+ * set the cache directory
+ * - command: "dir <name>"
+ */
+static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
+{
+        char *dir;
+
+        _enter(",%s", args);
+
+        if (!*args) {
+                kerror("Empty directory specified");
+                return -EINVAL;
+        }
+
+        if (cache->rootdirname) {
+                kerror("Second cache directory specified");
+                return -EEXIST;
+        }
+
+        dir = kstrdup(args, GFP_KERNEL);
+        if (!dir)
+                return -ENOMEM;
+
+        cache->rootdirname = dir;
+        return 0;
+}
+
+/*
+ * set the cache security context
+ * - command: "secctx <ctx>"
+ */
+static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
+{
+        char *secctx;
+
+        _enter(",%s", args);
+
+        if (!*args) {
+                kerror("Empty security context specified");
+                return -EINVAL;
+        }
+
+        if (cache->secctx) {
+                kerror("Second security context specified");
+                return -EINVAL;
+        }
+
+        secctx = kstrdup(args, GFP_KERNEL);
+        if (!secctx)
+                return -ENOMEM;
+
+        cache->secctx = secctx;
+        return 0;
+}
+
+/*
+ * set the cache tag
+ * - command: "tag <name>"
+ */
+static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
+{
+        char *tag;
+
+        _enter(",%s", args);
+
+        if (!*args) {
+                kerror("Empty tag specified");
+                return -EINVAL;
+        }
+
+        if (cache->tag)
+                return -EEXIST;
+
+        tag = kstrdup(args, GFP_KERNEL);
+        if (!tag)
+                return -ENOMEM;
+
+        cache->tag = tag;
+        return 0;
+}
+
+/*
+ * request a node in the cache be culled from the current working directory
+ * - command: "cull <name>"
+ */
+static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
+{
+        struct fs_struct *fs;
+        struct dentry *dir;
+        const struct cred *saved_cred;
+        int ret;
+
+        _enter(",%s", args);
+
+        if (strchr(args, '/'))
+                goto inval;
+
+        if (!test_bit(CACHEFILES_READY, &cache->flags)) {
+                kerror("cull applied to unready cache");
+                return -EIO;
+        }
+
+        if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
+                kerror("cull applied to dead cache");
+                return -EIO;
+        }
+
+        /* extract the directory dentry from the cwd */
+        fs = current->fs;
+        read_lock(&fs->lock);
+        dir = dget(fs->pwd.dentry);
+        read_unlock(&fs->lock);
+
+        if (!S_ISDIR(dir->d_inode->i_mode))
+                goto notdir;
+
+        cachefiles_begin_secure(cache, &saved_cred);
+        ret = cachefiles_cull(cache, dir, args);
+        cachefiles_end_secure(cache, saved_cred);
+
+        dput(dir);
+        _leave(" = %d", ret);
+        return ret;
+
+notdir:
+        dput(dir);
+        kerror("cull command requires dirfd to be a directory");
+        return -ENOTDIR;
+
+inval:
+        kerror("cull command requires dirfd and filename");
+        return -EINVAL;
+}
+
+/*
+ * set debugging mode
+ * - command: "debug <mask>"
+ */
+static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
+{
+        unsigned long mask;
+
+        _enter(",%s", args);
+
+        mask = simple_strtoul(args, &args, 0);
+        if (args[0] != '\0')
+                goto inval;
+
+        cachefiles_debug = mask;
+        _leave(" = 0");
+        return 0;
+
+inval:
+        kerror("debug command requires mask");
+        return -EINVAL;
+}
+
+/*
+ * find out whether an object in the current working directory is in use or not
+ * - command: "inuse <name>"
+ */
+static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
+{
+        struct fs_struct *fs;
+        struct dentry *dir;
+        const struct cred *saved_cred;
+        int ret;
+
+        //_enter(",%s", args);
+
+        if (strchr(args, '/'))
+                goto inval;
+
+        if (!test_bit(CACHEFILES_READY, &cache->flags)) {
+                kerror("inuse applied to unready cache");
+                return -EIO;
+        }
+
+        if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
+                kerror("inuse applied to dead cache");
+                return -EIO;
+        }
+
+        /* extract the directory dentry from the cwd */
+        fs = current->fs;
+        read_lock(&fs->lock);
+        dir = dget(fs->pwd.dentry);
+        read_unlock(&fs->lock);
+
+        if (!S_ISDIR(dir->d_inode->i_mode))
+                goto notdir;
+
+        cachefiles_begin_secure(cache, &saved_cred);
+        ret = cachefiles_check_in_use(cache, dir, args);
+        cachefiles_end_secure(cache, saved_cred);
+
+        dput(dir);
+        //_leave(" = %d", ret);
+        return ret;
+
+notdir:
+        dput(dir);
+        kerror("inuse command requires dirfd to be a directory");
+        return -ENOTDIR;
+
+inval:
+        kerror("inuse command requires dirfd and filename");
+        return -EINVAL;
+}
+
+/*
+ * see if we have space for a number of pages and/or a number of files in the
+ * cache
+ */
+int cachefiles_has_space(struct cachefiles_cache *cache,
+                         unsigned fnr, unsigned bnr)
+{
+        struct kstatfs stats;
+        int ret;
+
+        //_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
+        //       (unsigned long long) cache->frun,
+        //       (unsigned long long) cache->fcull,
+        //       (unsigned long long) cache->fstop,
+        //       (unsigned long long) cache->brun,
+        //       (unsigned long long) cache->bcull,
+        //       (unsigned long long) cache->bstop,
+        //       fnr, bnr);
+
+        /* find out how many pages of blockdev are available */
+        memset(&stats, 0, sizeof(stats));
+
+        ret = vfs_statfs(cache->mnt->mnt_root, &stats);
+        if (ret < 0) {
+                if (ret == -EIO)
+                        cachefiles_io_error(cache, "statfs failed");
+                _leave(" = %d", ret);
+                return ret;
+        }
+
+        stats.f_bavail >>= cache->bshift;
+
+        //_debug("avail %llu,%llu",
+        //       (unsigned long long) stats.f_ffree,
+        //       (unsigned long long) stats.f_bavail);
+
+        /* see if there is sufficient space */
+        if (stats.f_ffree > fnr)
+                stats.f_ffree -= fnr;
+        else
+                stats.f_ffree = 0;
+
+        if (stats.f_bavail > bnr)
+                stats.f_bavail -= bnr;
+        else
+                stats.f_bavail = 0;
+
+        ret = -ENOBUFS;
+        if (stats.f_ffree < cache->fstop ||
+            stats.f_bavail < cache->bstop)
+                goto begin_cull;
+
+        ret = 0;
+        if (stats.f_ffree < cache->fcull ||
+            stats.f_bavail < cache->bcull)
+                goto begin_cull;
+
+        if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
+            stats.f_ffree >= cache->frun &&
+            stats.f_bavail >= cache->brun &&
+            test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
+            ) {
+                _debug("cease culling");
+                cachefiles_state_changed(cache);
+        }
+
+        //_leave(" = 0");
+        return 0;
+
+begin_cull:
+        if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
+                _debug("### CULL CACHE ###");
+                cachefiles_state_changed(cache);
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
new file mode 100644
index 000000000000..1e962348d111
--- /dev/null
+++ b/fs/cachefiles/interface.c
@@ -0,0 +1,449 @@
+/* FS-Cache interface to CacheFiles
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/mount.h>
+#include <linux/buffer_head.h>
+#include "internal.h"
+
+#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
+
+struct cachefiles_lookup_data {
+        struct cachefiles_xattr *auxdata;       /* auxiliary data */
+        char                    *key;           /* key path */
+};
+
+static int cachefiles_attr_changed(struct fscache_object *_object);
+
+/*
+ * allocate an object record for a cookie lookup and prepare the lookup data
+ */
+static struct fscache_object *cachefiles_alloc_object(
+        struct fscache_cache *_cache,
+        struct fscache_cookie *cookie)
+{
+        struct cachefiles_lookup_data *lookup_data;
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        struct cachefiles_xattr *auxdata;
+        unsigned keylen, auxlen;
+        void *buffer;
+        char *key;
+
+        cache = container_of(_cache, struct cachefiles_cache, cache);
+
+        _enter("{%s},%p,", cache->cache.identifier, cookie);
+
+        lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL);
+        if (!lookup_data)
+                goto nomem_lookup_data;
+
+        /* create a new object record and a temporary leaf image */
+        object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
+        if (!object)
+                goto nomem_object;
+
+        ASSERTCMP(object->backer, ==, NULL);
+
+        BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+        atomic_set(&object->usage, 1);
+
+        fscache_object_init(&object->fscache, cookie, &cache->cache);
+
+        object->type = cookie->def->type;
+
+        /* get hold of the raw key
+         * - stick the length on the front and leave space on the back for the
+         *   encoder
+         */
+        buffer = kmalloc((2 + 512) + 3, GFP_KERNEL);
+        if (!buffer)
+                goto nomem_buffer;
+
+        keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512);
+        ASSERTCMP(keylen, <, 512);
+
+        *(uint16_t *)buffer = keylen;
+        ((char *)buffer)[keylen + 2] = 0;
+        ((char *)buffer)[keylen + 3] = 0;
+        ((char *)buffer)[keylen + 4] = 0;
+
+        /* turn the raw key into something that can work with as a filename */
+        key = cachefiles_cook_key(buffer, keylen + 2, object->type);
+        if (!key)
+                goto nomem_key;
+
+        /* get hold of the auxiliary data and prepend the object type */
+        auxdata = buffer;
+        auxlen = 0;
+        if (cookie->def->get_aux) {
+                auxlen = cookie->def->get_aux(cookie->netfs_data,
+                                              auxdata->data, 511);
+                ASSERTCMP(auxlen, <, 511);
+        }
+
+        auxdata->len = auxlen + 1;
+        auxdata->type = cookie->def->type;
+
+        lookup_data->auxdata = auxdata;
+        lookup_data->key = key;
+        object->lookup_data = lookup_data;
+
+        _leave(" = %p [%p]", &object->fscache, lookup_data);
+        return &object->fscache;
+
+nomem_key:
+        kfree(buffer);
+nomem_buffer:
+        BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+        kmem_cache_free(cachefiles_object_jar, object);
+        fscache_object_destroyed(&cache->cache);
+nomem_object:
+        kfree(lookup_data);
+nomem_lookup_data:
+        _leave(" = -ENOMEM");
+        return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * attempt to look up the nominated node in this cache
+ */
+static void cachefiles_lookup_object(struct fscache_object *_object)
+{
+        struct cachefiles_lookup_data *lookup_data;
+        struct cachefiles_object *parent, *object;
+        struct cachefiles_cache *cache;
+        const struct cred *saved_cred;
+        int ret;
+
+        _enter("{OBJ%x}", _object->debug_id);
+
+        cache = container_of(_object->cache, struct cachefiles_cache, cache);
+        parent = container_of(_object->parent,
+                              struct cachefiles_object, fscache);
+        object = container_of(_object, struct cachefiles_object, fscache);
+        lookup_data = object->lookup_data;
+
+        ASSERTCMP(lookup_data, !=, NULL);
+
+        /* look up the key, creating any missing bits */
+        cachefiles_begin_secure(cache, &saved_cred);
+        ret = cachefiles_walk_to_object(parent, object,
+                                        lookup_data->key,
+                                        lookup_data->auxdata);
+        cachefiles_end_secure(cache, saved_cred);
+
+        /* polish off by setting the attributes of non-index files */
+        if (ret == 0 &&
+            object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
+                cachefiles_attr_changed(&object->fscache);
+
+        if (ret < 0) {
+                printk(KERN_WARNING "CacheFiles: Lookup failed error %d\n",
+                       ret);
+                fscache_object_lookup_error(&object->fscache);
+        }
+
+        _leave(" [%d]", ret);
+}
+
+/*
+ * indication of lookup completion
+ */
+static void cachefiles_lookup_complete(struct fscache_object *_object)
+{
+        struct cachefiles_object *object;
+
+        object = container_of(_object, struct cachefiles_object, fscache);
+
+        _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
+
+        if (object->lookup_data) {
+                kfree(object->lookup_data->key);
+                kfree(object->lookup_data->auxdata);
+                kfree(object->lookup_data);
+                object->lookup_data = NULL;
+        }
+}
+
+/*
+ * increment the usage count on an inode object (may fail if unmounting)
+ */
+static
+struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
+{
+        struct cachefiles_object *object =
+                container_of(_object, struct cachefiles_object, fscache);
+
+        _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
+
+#ifdef CACHEFILES_DEBUG_SLAB
+        ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+        atomic_inc(&object->usage);
+        return &object->fscache;
+}
+
+/*
+ * update the auxilliary data for an object object on disk
+ */
+static void cachefiles_update_object(struct fscache_object *_object)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_xattr *auxdata;
+        struct cachefiles_cache *cache;
+        struct fscache_cookie *cookie;
+        const struct cred *saved_cred;
+        unsigned auxlen;
+
+        _enter("{OBJ%x}", _object->debug_id);
+
+        object = container_of(_object, struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache, struct cachefiles_cache,
+                             cache);
+        cookie = object->fscache.cookie;
+
+        if (!cookie->def->get_aux) {
+                _leave(" [no aux]");
+                return;
+        }
+
+        auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL);
+        if (!auxdata) {
+                _leave(" [nomem]");
+                return;
+        }
+
+        auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
+        ASSERTCMP(auxlen, <, 511);
+
+        auxdata->len = auxlen + 1;
+        auxdata->type = cookie->def->type;
+
+        cachefiles_begin_secure(cache, &saved_cred);
+        cachefiles_update_object_xattr(object, auxdata);
+        cachefiles_end_secure(cache, saved_cred);
+        kfree(auxdata);
+        _leave("");
+}
+
+/*
+ * discard the resources pinned by an object and effect retirement if
+ * requested
+ */
+static void cachefiles_drop_object(struct fscache_object *_object)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        const struct cred *saved_cred;
+
+        ASSERT(_object);
+
+        object = container_of(_object, struct cachefiles_object, fscache);
+
+        _enter("{OBJ%x,%d}",
+               object->fscache.debug_id, atomic_read(&object->usage));
+
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+#ifdef CACHEFILES_DEBUG_SLAB
+        ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+        /* delete retired objects */
+        if (object->fscache.state == FSCACHE_OBJECT_RECYCLING &&
+            _object != cache->cache.fsdef
+            ) {
+                _debug("- retire object OBJ%x", object->fscache.debug_id);
+                cachefiles_begin_secure(cache, &saved_cred);
+                cachefiles_delete_object(cache, object);
+                cachefiles_end_secure(cache, saved_cred);
+        }
+
+        /* close the filesystem stuff attached to the object */
+        if (object->backer != object->dentry)
+                dput(object->backer);
+        object->backer = NULL;
+
+        /* note that the object is now inactive */
+        if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
+                write_lock(&cache->active_lock);
+                if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE,
+                                        &object->flags))
+                        BUG();
+                rb_erase(&object->active_node, &cache->active_nodes);
+                wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
+                write_unlock(&cache->active_lock);
+        }
+
+        dput(object->dentry);
+        object->dentry = NULL;
+
+        _leave("");
+}
+
+/*
+ * dispose of a reference to an object
+ */
+static void cachefiles_put_object(struct fscache_object *_object)
+{
+        struct cachefiles_object *object;
+        struct fscache_cache *cache;
+
+        ASSERT(_object);
+
+        object = container_of(_object, struct cachefiles_object, fscache);
+
+        _enter("{OBJ%x,%d}",
+               object->fscache.debug_id, atomic_read(&object->usage));
+
+#ifdef CACHEFILES_DEBUG_SLAB
+        ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+        ASSERTIFCMP(object->fscache.parent,
+                    object->fscache.parent->n_children, >, 0);
+
+        if (atomic_dec_and_test(&object->usage)) {
+                _debug("- kill object OBJ%x", object->fscache.debug_id);
+
+                ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+                ASSERTCMP(object->fscache.parent, ==, NULL);
+                ASSERTCMP(object->backer, ==, NULL);
+                ASSERTCMP(object->dentry, ==, NULL);
+                ASSERTCMP(object->fscache.n_ops, ==, 0);
+                ASSERTCMP(object->fscache.n_children, ==, 0);
+
+                if (object->lookup_data) {
+                        kfree(object->lookup_data->key);
+                        kfree(object->lookup_data->auxdata);
+                        kfree(object->lookup_data);
+                        object->lookup_data = NULL;
+                }
+
+                cache = object->fscache.cache;
+                kmem_cache_free(cachefiles_object_jar, object);
+                fscache_object_destroyed(cache);
+        }
+
+        _leave("");
+}
+
+/*
+ * sync a cache
+ */
+static void cachefiles_sync_cache(struct fscache_cache *_cache)
+{
+        struct cachefiles_cache *cache;
+        const struct cred *saved_cred;
+        int ret;
+
+        _enter("%p", _cache);
+
+        cache = container_of(_cache, struct cachefiles_cache, cache);
+
+        /* make sure all pages pinned by operations on behalf of the netfs are
+         * written to disc */
+        cachefiles_begin_secure(cache, &saved_cred);
+        ret = fsync_super(cache->mnt->mnt_sb);
+        cachefiles_end_secure(cache, saved_cred);
+
+        if (ret == -EIO)
+                cachefiles_io_error(cache,
+                                    "Attempt to sync backing fs superblock"
+                                    " returned error %d",
+                                    ret);
+}
+
+/*
+ * notification the attributes on an object have changed
+ * - called with reads/writes excluded by FS-Cache
+ */
+static int cachefiles_attr_changed(struct fscache_object *_object)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        const struct cred *saved_cred;
+        struct iattr newattrs;
+        uint64_t ni_size;
+        loff_t oi_size;
+        int ret;
+
+        _object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size);
+
+        _enter("{OBJ%x},[%llu]",
+               _object->debug_id, (unsigned long long) ni_size);
+
+        object = container_of(_object, struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        if (ni_size == object->i_size)
+                return 0;
+
+        if (!object->backer)
+                return -ENOBUFS;
+
+        ASSERT(S_ISREG(object->backer->d_inode->i_mode));
+
+        fscache_set_store_limit(&object->fscache, ni_size);
+
+        oi_size = i_size_read(object->backer->d_inode);
+        if (oi_size == ni_size)
+                return 0;
+
+        newattrs.ia_size = ni_size;
+        newattrs.ia_valid = ATTR_SIZE;
+
+        cachefiles_begin_secure(cache, &saved_cred);
+        mutex_lock(&object->backer->d_inode->i_mutex);
+        ret = notify_change(object->backer, &newattrs);
+        mutex_unlock(&object->backer->d_inode->i_mutex);
+        cachefiles_end_secure(cache, saved_cred);
+
+        if (ret == -EIO) {
+                fscache_set_store_limit(&object->fscache, 0);
+                cachefiles_io_error_obj(object, "Size set failed");
+                ret = -ENOBUFS;
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * dissociate a cache from all the pages it was backing
+ */
+static void cachefiles_dissociate_pages(struct fscache_cache *cache)
+{
+        _enter("");
+}
+
+const struct fscache_cache_ops cachefiles_cache_ops = {
+        .name                   = "cachefiles",
+        .alloc_object           = cachefiles_alloc_object,
+        .lookup_object          = cachefiles_lookup_object,
+        .lookup_complete        = cachefiles_lookup_complete,
+        .grab_object            = cachefiles_grab_object,
+        .update_object          = cachefiles_update_object,
+        .drop_object            = cachefiles_drop_object,
+        .put_object             = cachefiles_put_object,
+        .sync_cache             = cachefiles_sync_cache,
+        .attr_changed           = cachefiles_attr_changed,
+        .read_or_alloc_page     = cachefiles_read_or_alloc_page,
+        .read_or_alloc_pages    = cachefiles_read_or_alloc_pages,
+        .allocate_page          = cachefiles_allocate_page,
+        .allocate_pages         = cachefiles_allocate_pages,
+        .write_page             = cachefiles_write_page,
+        .uncache_page           = cachefiles_uncache_page,
+        .dissociate_pages       = cachefiles_dissociate_pages,
+};
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
new file mode 100644
index 000000000000..19218e1463d6
--- /dev/null
+++ b/fs/cachefiles/internal.h
@@ -0,0 +1,360 @@
+/* General netfs cache on cache files internal defs
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/fscache-cache.h>
+#include <linux/timer.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/security.h>
+
+struct cachefiles_cache;
+struct cachefiles_object;
+
+extern unsigned cachefiles_debug;
+#define CACHEFILES_DEBUG_KENTER 1
+#define CACHEFILES_DEBUG_KLEAVE 2
+#define CACHEFILES_DEBUG_KDEBUG 4
+
+/*
+ * node records
+ */
+struct cachefiles_object {
+        struct fscache_object           fscache;        /* fscache handle */
+        struct cachefiles_lookup_data   *lookup_data;   /* cached lookup data */
+        struct dentry                   *dentry;        /* the file/dir representing this object */
+        struct dentry                   *backer;        /* backing file */
+        loff_t                          i_size;         /* object size */
+        unsigned long                   flags;
+#define CACHEFILES_OBJECT_ACTIVE        0               /* T if marked active */
+        atomic_t                        usage;          /* object usage count */
+        uint8_t                         type;           /* object type */
+        uint8_t                         new;            /* T if object new */
+        spinlock_t                      work_lock;
+        struct rb_node                  active_node;    /* link in active tree (dentry is key) */
+};
+
+extern struct kmem_cache *cachefiles_object_jar;
+
+/*
+ * Cache files cache definition
+ */
+struct cachefiles_cache {
+        struct fscache_cache            cache;          /* FS-Cache record */
+        struct vfsmount                 *mnt;           /* mountpoint holding the cache */
+        struct dentry                   *graveyard;     /* directory into which dead objects go */
+        struct file                     *cachefilesd;   /* manager daemon handle */
+        const struct cred               *cache_cred;    /* security override for accessing cache */
+        struct mutex                    daemon_mutex;   /* command serialisation mutex */
+        wait_queue_head_t               daemon_pollwq;  /* poll waitqueue for daemon */
+        struct rb_root                  active_nodes;   /* active nodes (can't be culled) */
+        rwlock_t                        active_lock;    /* lock for active_nodes */
+        atomic_t                        gravecounter;   /* graveyard uniquifier */
+        unsigned                        frun_percent;   /* when to stop culling (% files) */
+        unsigned                        fcull_percent;  /* when to start culling (% files) */
+        unsigned                        fstop_percent;  /* when to stop allocating (% files) */
+        unsigned                        brun_percent;   /* when to stop culling (% blocks) */
+        unsigned                        bcull_percent;  /* when to start culling (% blocks) */
+        unsigned                        bstop_percent;  /* when to stop allocating (% blocks) */
+        unsigned                        bsize;          /* cache's block size */
+        unsigned                        bshift;         /* min(ilog2(PAGE_SIZE / bsize), 0) */
+        uint64_t                        frun;           /* when to stop culling */
+        uint64_t                        fcull;          /* when to start culling */
+        uint64_t                        fstop;          /* when to stop allocating */
+        sector_t                        brun;           /* when to stop culling */
+        sector_t                        bcull;          /* when to start culling */
+        sector_t                        bstop;          /* when to stop allocating */
+        unsigned long                   flags;
+#define CACHEFILES_READY                0       /* T if cache prepared */
+#define CACHEFILES_DEAD                 1       /* T if cache dead */
+#define CACHEFILES_CULLING              2       /* T if cull engaged */
+#define CACHEFILES_STATE_CHANGED        3       /* T if state changed (poll trigger) */
+        char                            *rootdirname;   /* name of cache root directory */
+        char                            *secctx;        /* LSM security context */
+        char                            *tag;           /* cache binding tag */
+};
+
+/*
+ * backing file read tracking
+ */
+struct cachefiles_one_read {
+        wait_queue_t                    monitor;        /* link into monitored waitqueue */
+        struct page                     *back_page;     /* backing file page we're waiting for */
+        struct page                     *netfs_page;    /* netfs page we're going to fill */
+        struct fscache_retrieval        *op;            /* retrieval op covering this */
+        struct list_head                op_link;        /* link in op's todo list */
+};
+
+/*
+ * backing file write tracking
+ */
+struct cachefiles_one_write {
+        struct page                     *netfs_page;    /* netfs page to copy */
+        struct cachefiles_object        *object;
+        struct list_head                obj_link;       /* link in object's lists */
+        fscache_rw_complete_t           end_io_func;
+        void                            *context;
+};
+
+/*
+ * auxiliary data xattr buffer
+ */
+struct cachefiles_xattr {
+        uint16_t                        len;
+        uint8_t                         type;
+        uint8_t                         data[];
+};
+
+/*
+ * note change of state for daemon
+ */
+static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
+{
+        set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
+        wake_up_all(&cache->daemon_pollwq);
+}
+
+/*
+ * cf-bind.c
+ */
+extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
+extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);
+
+/*
+ * cf-daemon.c
+ */
+extern const struct file_operations cachefiles_daemon_fops;
+
+extern int cachefiles_has_space(struct cachefiles_cache *cache,
+                                unsigned fnr, unsigned bnr);
+
+/*
+ * cf-interface.c
+ */
+extern const struct fscache_cache_ops cachefiles_cache_ops;
+
+/*
+ * cf-key.c
+ */
+extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);
+
+/*
+ * cf-namei.c
+ */
+extern int cachefiles_delete_object(struct cachefiles_cache *cache,
+                                    struct cachefiles_object *object);
+extern int cachefiles_walk_to_object(struct cachefiles_object *parent,
+                                     struct cachefiles_object *object,
+                                     const char *key,
+                                     struct cachefiles_xattr *auxdata);
+extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
+                                               struct dentry *dir,
+                                               const char *name);
+
+extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
+                           char *filename);
+
+extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
+                                   struct dentry *dir, char *filename);
+
+/*
+ * cf-proc.c
+ */
+#ifdef CONFIG_CACHEFILES_HISTOGRAM
+extern atomic_t cachefiles_lookup_histogram[HZ];
+extern atomic_t cachefiles_mkdir_histogram[HZ];
+extern atomic_t cachefiles_create_histogram[HZ];
+
+extern int __init cachefiles_proc_init(void);
+extern void cachefiles_proc_cleanup(void);
+static inline
+void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
+{
+        unsigned long jif = jiffies - start_jif;
+        if (jif >= HZ)
+                jif = HZ - 1;
+        atomic_inc(&histogram[jif]);
+}
+
+#else
+#define cachefiles_proc_init()          (0)
+#define cachefiles_proc_cleanup()       do {} while (0)
+#define cachefiles_hist(hist, start_jif) do {} while (0)
+#endif
+
+/*
+ * cf-rdwr.c
+ */
+extern int cachefiles_read_or_alloc_page(struct fscache_retrieval *,
+                                         struct page *, gfp_t);
+extern int cachefiles_read_or_alloc_pages(struct fscache_retrieval *,
+                                          struct list_head *, unsigned *,
+                                          gfp_t);
+extern int cachefiles_allocate_page(struct fscache_retrieval *, struct page *,
+                                    gfp_t);
+extern int cachefiles_allocate_pages(struct fscache_retrieval *,
+                                     struct list_head *, unsigned *, gfp_t);
+extern int cachefiles_write_page(struct fscache_storage *, struct page *);
+extern void cachefiles_uncache_page(struct fscache_object *, struct page *);
+
+/*
+ * cf-security.c
+ */
+extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
+extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
+                                               struct dentry *root,
+                                               const struct cred **_saved_cred);
+
+static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
+                                           const struct cred **_saved_cred)
+{
+        *_saved_cred = override_creds(cache->cache_cred);
+}
+
+static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
+                                         const struct cred *saved_cred)
+{
+        revert_creds(saved_cred);
+}
+
+/*
+ * cf-xattr.c
+ */
+extern int cachefiles_check_object_type(struct cachefiles_object *object);
+extern int cachefiles_set_object_xattr(struct cachefiles_object *object,
+                                       struct cachefiles_xattr *auxdata);
+extern int cachefiles_update_object_xattr(struct cachefiles_object *object,
+                                          struct cachefiles_xattr *auxdata);
+extern int cachefiles_check_object_xattr(struct cachefiles_object *object,
+                                         struct cachefiles_xattr *auxdata);
+extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
+                                          struct dentry *dentry);
+
+
+/*
+ * error handling
+ */
+#define kerror(FMT, ...) printk(KERN_ERR "CacheFiles: "FMT"\n", ##__VA_ARGS__)
+
+#define cachefiles_io_error(___cache, FMT, ...)         \
+do {                                                    \
+        kerror("I/O Error: " FMT, ##__VA_ARGS__);       \
+        fscache_io_error(&(___cache)->cache);           \
+        set_bit(CACHEFILES_DEAD, &(___cache)->flags);   \
+} while (0)
+
+#define cachefiles_io_error_obj(object, FMT, ...)                       \
+do {                                                                    \
+        struct cachefiles_cache *___cache;                              \
+                                                                        \
+        ___cache = container_of((object)->fscache.cache,                \
+                                struct cachefiles_cache, cache);        \
+        cachefiles_io_error(___cache, FMT, ##__VA_ARGS__);              \
+} while (0)
+
+
+/*
+ * debug tracing
+ */
+#define dbgprintk(FMT, ...) \
+        printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
+
+/* make sure we maintain the format strings, even when debugging is disabled */
+static inline void _dbprintk(const char *fmt, ...)
+        __attribute__((format(printf, 1, 2)));
+static inline void _dbprintk(const char *fmt, ...)
+{
+}
+
+#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
+
+
+#if defined(__KDEBUG)
+#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
+#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
+#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
+
+#elif defined(CONFIG_CACHEFILES_DEBUG)
+#define _enter(FMT, ...)                                \
+do {                                                    \
+        if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
+                kenter(FMT, ##__VA_ARGS__);             \
+} while (0)
+
+#define _leave(FMT, ...)                                \
+do {                                                    \
+        if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
+                kleave(FMT, ##__VA_ARGS__);             \
+} while (0)
+
+#define _debug(FMT, ...)                                \
+do {                                                    \
+        if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
+                kdebug(FMT, ##__VA_ARGS__);             \
+} while (0)
+
+#else
+#define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
+#define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
+#define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
+#endif
+
+#if 1 /* defined(__KDEBUGALL) */
+
+#define ASSERT(X)                                                       \
+do {                                                                    \
+        if (unlikely(!(X))) {                                           \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#define ASSERTCMP(X, OP, Y)                                             \
+do {                                                                    \
+        if (unlikely(!((X) OP (Y)))) {                                  \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
+                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
+                       (unsigned long)(X), (unsigned long)(Y));         \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#define ASSERTIF(C, X)                                                  \
+do {                                                                    \
+        if (unlikely((C) && !(X))) {                                    \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#define ASSERTIFCMP(C, X, OP, Y)                                        \
+do {                                                                    \
+        if (unlikely((C) && !((X) OP (Y)))) {                           \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "CacheFiles: Assertion failed\n");      \
+                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
+                       (unsigned long)(X), (unsigned long)(Y));         \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#else
+
+#define ASSERT(X)                       do {} while (0)
+#define ASSERTCMP(X, OP, Y)             do {} while (0)
+#define ASSERTIF(C, X)                  do {} while (0)
+#define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
+
+#endif
diff --git a/fs/cachefiles/key.c b/fs/cachefiles/key.c
new file mode 100644
index 000000000000..81b8b2b3a674
--- /dev/null
+++ b/fs/cachefiles/key.c
@@ -0,0 +1,159 @@
+/* Key to pathname encoder
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/slab.h>
+#include "internal.h"
+
+static const char cachefiles_charmap[64] =
+        "0123456789"                    /* 0 - 9 */
+        "abcdefghijklmnopqrstuvwxyz"    /* 10 - 35 */
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"    /* 36 - 61 */
+        "_-"                            /* 62 - 63 */
+        ;
+
+static const char cachefiles_filecharmap[256] = {
+        /* we skip space and tab and control chars */
+        [33 ... 46] = 1,                /* '!' -> '.' */
+        /* we skip '/' as it's significant to pathwalk */
+        [48 ... 127] = 1,               /* '0' -> '~' */
+};
+
+/*
+ * turn the raw key into something cooked
+ * - the raw key should include the length in the two bytes at the front
+ * - the key may be up to 514 bytes in length (including the length word)
+ *   - "base64" encode the strange keys, mapping 3 bytes of raw to four of
+ *     cooked
+ *   - need to cut the cooked key into 252 char lengths (189 raw bytes)
+ */
+char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type)
+{
+        unsigned char csum, ch;
+        unsigned int acc;
+        char *key;
+        int loop, len, max, seg, mark, print;
+
+        _enter(",%d", keylen);
+
+        BUG_ON(keylen < 2 || keylen > 514);
+
+        csum = raw[0] + raw[1];
+        print = 1;
+        for (loop = 2; loop < keylen; loop++) {
+                ch = raw[loop];
+                csum += ch;
+                print &= cachefiles_filecharmap[ch];
+        }
+
+        if (print) {
+                /* if the path is usable ASCII, then we render it directly */
+                max = keylen - 2;
+                max += 2;       /* two base64'd length chars on the front */
+                max += 5;       /* @checksum/M */
+                max += 3 * 2;   /* maximum number of segment dividers (".../M")
+                                 * is ((514 + 251) / 252) = 3
+                                 */
+                max += 1;       /* NUL on end */
+        } else {
+                /* calculate the maximum length of the cooked key */
+                keylen = (keylen + 2) / 3;
+
+                max = keylen * 4;
+                max += 5;       /* @checksum/M */
+                max += 3 * 2;   /* maximum number of segment dividers (".../M")
+                                 * is ((514 + 188) / 189) = 3
+                                 */
+                max += 1;       /* NUL on end */
+        }
+
+        max += 1;       /* 2nd NUL on end */
+
+        _debug("max: %d", max);
+
+        key = kmalloc(max, GFP_KERNEL);
+        if (!key)
+                return NULL;
+
+        len = 0;
+
+        /* build the cooked key */
+        sprintf(key, "@%02x%c+", (unsigned) csum, 0);
+        len = 5;
+        mark = len - 1;
+
+        if (print) {
+                acc = *(uint16_t *) raw;
+                raw += 2;
+
+                key[len + 1] = cachefiles_charmap[acc & 63];
+                acc >>= 6;
+                key[len] = cachefiles_charmap[acc & 63];
+                len += 2;
+
+                seg = 250;
+                for (loop = keylen; loop > 0; loop--) {
+                        if (seg <= 0) {
+                                key[len++] = '\0';
+                                mark = len;
+                                key[len++] = '+';
+                                seg = 252;
+                        }
+
+                        key[len++] = *raw++;
+                        ASSERT(len < max);
+                }
+
+                switch (type) {
+                case FSCACHE_COOKIE_TYPE_INDEX:         type = 'I';     break;
+                case FSCACHE_COOKIE_TYPE_DATAFILE:      type = 'D';     break;
+                default:                                type = 'S';     break;
+                }
+        } else {
+                seg = 252;
+                for (loop = keylen; loop > 0; loop--) {
+                        if (seg <= 0) {
+                                key[len++] = '\0';
+                                mark = len;
+                                key[len++] = '+';
+                                seg = 252;
+                        }
+
+                        acc = *raw++;
+                        acc |= *raw++ << 8;
+                        acc |= *raw++ << 16;
+
+                        _debug("acc: %06x", acc);
+
+                        key[len++] = cachefiles_charmap[acc & 63];
+                        acc >>= 6;
+                        key[len++] = cachefiles_charmap[acc & 63];
+                        acc >>= 6;
+                        key[len++] = cachefiles_charmap[acc & 63];
+                        acc >>= 6;
+                        key[len++] = cachefiles_charmap[acc & 63];
+
+                        ASSERT(len < max);
+                }
+
+                switch (type) {
+                case FSCACHE_COOKIE_TYPE_INDEX:         type = 'J';     break;
+                case FSCACHE_COOKIE_TYPE_DATAFILE:      type = 'E';     break;
+                default:                                type = 'T';     break;
+                }
+        }
+
+        key[mark] = type;
+        key[len++] = 0;
+        key[len] = 0;
+
+        _leave(" = %p %d", key, len);
+        return key;
+}
diff --git a/fs/cachefiles/main.c b/fs/cachefiles/main.c
new file mode 100644
index 000000000000..4bfa8cf43bf5
--- /dev/null
+++ b/fs/cachefiles/main.c
@@ -0,0 +1,106 @@
+/* Network filesystem caching backend to use cache files on a premounted
+ * filesystem
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/statfs.h>
+#include <linux/sysctl.h>
+#include <linux/miscdevice.h>
+#include "internal.h"
+
+unsigned cachefiles_debug;
+module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
+
+MODULE_DESCRIPTION("Mounted-filesystem based cache");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+struct kmem_cache *cachefiles_object_jar;
+
+static struct miscdevice cachefiles_dev = {
+        .minor  = MISC_DYNAMIC_MINOR,
+        .name   = "cachefiles",
+        .fops   = &cachefiles_daemon_fops,
+};
+
+static void cachefiles_object_init_once(void *_object)
+{
+        struct cachefiles_object *object = _object;
+
+        memset(object, 0, sizeof(*object));
+        spin_lock_init(&object->work_lock);
+}
+
+/*
+ * initialise the fs caching module
+ */
+static int __init cachefiles_init(void)
+{
+        int ret;
+
+        ret = misc_register(&cachefiles_dev);
+        if (ret < 0)
+                goto error_dev;
+
+        /* create an object jar */
+        ret = -ENOMEM;
+        cachefiles_object_jar =
+                kmem_cache_create("cachefiles_object_jar",
+                                  sizeof(struct cachefiles_object),
+                                  0,
+                                  SLAB_HWCACHE_ALIGN,
+                                  cachefiles_object_init_once);
+        if (!cachefiles_object_jar) {
+                printk(KERN_NOTICE
+                       "CacheFiles: Failed to allocate an object jar\n");
+                goto error_object_jar;
+        }
+
+        ret = cachefiles_proc_init();
+        if (ret < 0)
+                goto error_proc;
+
+        printk(KERN_INFO "CacheFiles: Loaded\n");
+        return 0;
+
+error_proc:
+        kmem_cache_destroy(cachefiles_object_jar);
+error_object_jar:
+        misc_deregister(&cachefiles_dev);
+error_dev:
+        kerror("failed to register: %d", ret);
+        return ret;
+}
+
+fs_initcall(cachefiles_init);
+
+/*
+ * clean up on module removal
+ */
+static void __exit cachefiles_exit(void)
+{
+        printk(KERN_INFO "CacheFiles: Unloading\n");
+
+        cachefiles_proc_cleanup();
+        kmem_cache_destroy(cachefiles_object_jar);
+        misc_deregister(&cachefiles_dev);
+}
+
+module_exit(cachefiles_exit);
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
new file mode 100644
index 000000000000..4ce818ae39ea
--- /dev/null
+++ b/fs/cachefiles/namei.c
@@ -0,0 +1,771 @@
+/* CacheFiles path walking and related routines
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/xattr.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include "internal.h"
+
+static int cachefiles_wait_bit(void *flags)
+{
+        schedule();
+        return 0;
+}
+
+/*
+ * record the fact that an object is now active
+ */
+static void cachefiles_mark_object_active(struct cachefiles_cache *cache,
+                                          struct cachefiles_object *object)
+{
+        struct cachefiles_object *xobject;
+        struct rb_node **_p, *_parent = NULL;
+        struct dentry *dentry;
+
+        _enter(",%p", object);
+
+try_again:
+        write_lock(&cache->active_lock);
+
+        if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
+                BUG();
+
+        dentry = object->dentry;
+        _p = &cache->active_nodes.rb_node;
+        while (*_p) {
+                _parent = *_p;
+                xobject = rb_entry(_parent,
+                                   struct cachefiles_object, active_node);
+
+                ASSERT(xobject != object);
+
+                if (xobject->dentry > dentry)
+                        _p = &(*_p)->rb_left;
+                else if (xobject->dentry < dentry)
+                        _p = &(*_p)->rb_right;
+                else
+                        goto wait_for_old_object;
+        }
+
+        rb_link_node(&object->active_node, _parent, _p);
+        rb_insert_color(&object->active_node, &cache->active_nodes);
+
+        write_unlock(&cache->active_lock);
+        _leave("");
+        return;
+
+        /* an old object from a previous incarnation is hogging the slot - we
+         * need to wait for it to be destroyed */
+wait_for_old_object:
+        if (xobject->fscache.state < FSCACHE_OBJECT_DYING) {
+                printk(KERN_ERR "\n");
+                printk(KERN_ERR "CacheFiles: Error:"
+                       " Unexpected object collision\n");
+                printk(KERN_ERR "xobject: OBJ%x\n",
+                       xobject->fscache.debug_id);
+                printk(KERN_ERR "xobjstate=%s\n",
+                       fscache_object_states[xobject->fscache.state]);
+                printk(KERN_ERR "xobjflags=%lx\n", xobject->fscache.flags);
+                printk(KERN_ERR "xobjevent=%lx [%lx]\n",
+                       xobject->fscache.events, xobject->fscache.event_mask);
+                printk(KERN_ERR "xops=%u inp=%u exc=%u\n",
+                       xobject->fscache.n_ops, xobject->fscache.n_in_progress,
+                       xobject->fscache.n_exclusive);
+                printk(KERN_ERR "xcookie=%p [pr=%p nd=%p fl=%lx]\n",
+                       xobject->fscache.cookie,
+                       xobject->fscache.cookie->parent,
+                       xobject->fscache.cookie->netfs_data,
+                       xobject->fscache.cookie->flags);
+                printk(KERN_ERR "xparent=%p\n",
+                       xobject->fscache.parent);
+                printk(KERN_ERR "object: OBJ%x\n",
+                       object->fscache.debug_id);
+                printk(KERN_ERR "cookie=%p [pr=%p nd=%p fl=%lx]\n",
+                       object->fscache.cookie,
+                       object->fscache.cookie->parent,
+                       object->fscache.cookie->netfs_data,
+                       object->fscache.cookie->flags);
+                printk(KERN_ERR "parent=%p\n",
+                       object->fscache.parent);
+                BUG();
+        }
+        atomic_inc(&xobject->usage);
+        write_unlock(&cache->active_lock);
+
+        _debug(">>> wait");
+        wait_on_bit(&xobject->flags, CACHEFILES_OBJECT_ACTIVE,
+                    cachefiles_wait_bit, TASK_UNINTERRUPTIBLE);
+        _debug("<<< waited");
+
+        cache->cache.ops->put_object(&xobject->fscache);
+        goto try_again;
+}
+
+/*
+ * delete an object representation from the cache
+ * - file backed objects are unlinked
+ * - directory backed objects are stuffed into the graveyard for userspace to
+ *   delete
+ * - unlocks the directory mutex
+ */
+static int cachefiles_bury_object(struct cachefiles_cache *cache,
+                                  struct dentry *dir,
+                                  struct dentry *rep)
+{
+        struct dentry *grave, *trap;
+        char nbuffer[8 + 8 + 1];
+        int ret;
+
+        _enter(",'%*.*s','%*.*s'",
+               dir->d_name.len, dir->d_name.len, dir->d_name.name,
+               rep->d_name.len, rep->d_name.len, rep->d_name.name);
+
+        /* non-directories can just be unlinked */
+        if (!S_ISDIR(rep->d_inode->i_mode)) {
+                _debug("unlink stale object");
+                ret = vfs_unlink(dir->d_inode, rep);
+
+                mutex_unlock(&dir->d_inode->i_mutex);
+
+                if (ret == -EIO)
+                        cachefiles_io_error(cache, "Unlink failed");
+
+                _leave(" = %d", ret);
+                return ret;
+        }
+
+        /* directories have to be moved to the graveyard */
+        _debug("move stale object to graveyard");
+        mutex_unlock(&dir->d_inode->i_mutex);
+
+try_again:
+        /* first step is to make up a grave dentry in the graveyard */
+        sprintf(nbuffer, "%08x%08x",
+                (uint32_t) get_seconds(),
+                (uint32_t) atomic_inc_return(&cache->gravecounter));
+
+        /* do the multiway lock magic */
+        trap = lock_rename(cache->graveyard, dir);
+
+        /* do some checks before getting the grave dentry */
+        if (rep->d_parent != dir) {
+                /* the entry was probably culled when we dropped the parent dir
+                 * lock */
+                unlock_rename(cache->graveyard, dir);
+                _leave(" = 0 [culled?]");
+                return 0;
+        }
+
+        if (!S_ISDIR(cache->graveyard->d_inode->i_mode)) {
+                unlock_rename(cache->graveyard, dir);
+                cachefiles_io_error(cache, "Graveyard no longer a directory");
+                return -EIO;
+        }
+
+        if (trap == rep) {
+                unlock_rename(cache->graveyard, dir);
+                cachefiles_io_error(cache, "May not make directory loop");
+                return -EIO;
+        }
+
+        if (d_mountpoint(rep)) {
+                unlock_rename(cache->graveyard, dir);
+                cachefiles_io_error(cache, "Mountpoint in cache");
+                return -EIO;
+        }
+
+        grave = lookup_one_len(nbuffer, cache->graveyard, strlen(nbuffer));
+        if (IS_ERR(grave)) {
+                unlock_rename(cache->graveyard, dir);
+
+                if (PTR_ERR(grave) == -ENOMEM) {
+                        _leave(" = -ENOMEM");
+                        return -ENOMEM;
+                }
+
+                cachefiles_io_error(cache, "Lookup error %ld",
+                                    PTR_ERR(grave));
+                return -EIO;
+        }
+
+        if (grave->d_inode) {
+                unlock_rename(cache->graveyard, dir);
+                dput(grave);
+                grave = NULL;
+                cond_resched();
+                goto try_again;
+        }
+
+        if (d_mountpoint(grave)) {
+                unlock_rename(cache->graveyard, dir);
+                dput(grave);
+                cachefiles_io_error(cache, "Mountpoint in graveyard");
+                return -EIO;
+        }
+
+        /* target should not be an ancestor of source */
+        if (trap == grave) {
+                unlock_rename(cache->graveyard, dir);
+                dput(grave);
+                cachefiles_io_error(cache, "May not make directory loop");
+                return -EIO;
+        }
+
+        /* attempt the rename */
+        ret = vfs_rename(dir->d_inode, rep, cache->graveyard->d_inode, grave);
+        if (ret != 0 && ret != -ENOMEM)
+                cachefiles_io_error(cache, "Rename failed with error %d", ret);
+
+        unlock_rename(cache->graveyard, dir);
+        dput(grave);
+        _leave(" = 0");
+        return 0;
+}
+
+/*
+ * delete an object representation from the cache
+ */
+int cachefiles_delete_object(struct cachefiles_cache *cache,
+                             struct cachefiles_object *object)
+{
+        struct dentry *dir;
+        int ret;
+
+        _enter(",{%p}", object->dentry);
+
+        ASSERT(object->dentry);
+        ASSERT(object->dentry->d_inode);
+        ASSERT(object->dentry->d_parent);
+
+        dir = dget_parent(object->dentry);
+
+        mutex_lock(&dir->d_inode->i_mutex);
+        ret = cachefiles_bury_object(cache, dir, object->dentry);
+
+        dput(dir);
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * walk from the parent object to the child object through the backing
+ * filesystem, creating directories as we go
+ */
+int cachefiles_walk_to_object(struct cachefiles_object *parent,
+                              struct cachefiles_object *object,
+                              const char *key,
+                              struct cachefiles_xattr *auxdata)
+{
+        struct cachefiles_cache *cache;
+        struct dentry *dir, *next = NULL;
+        unsigned long start;
+        const char *name;
+        int ret, nlen;
+
+        _enter("{%p},,%s,", parent->dentry, key);
+
+        cache = container_of(parent->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        ASSERT(parent->dentry);
+        ASSERT(parent->dentry->d_inode);
+
+        if (!(S_ISDIR(parent->dentry->d_inode->i_mode))) {
+                // TODO: convert file to dir
+                _leave("looking up in none directory");
+                return -ENOBUFS;
+        }
+
+        dir = dget(parent->dentry);
+
+advance:
+        /* attempt to transit the first directory component */
+        name = key;
+        nlen = strlen(key);
+
+        /* key ends in a double NUL */
+        key = key + nlen + 1;
+        if (!*key)
+                key = NULL;
+
+lookup_again:
+        /* search the current directory for the element name */
+        _debug("lookup '%s'", name);
+
+        mutex_lock(&dir->d_inode->i_mutex);
+
+        start = jiffies;
+        next = lookup_one_len(name, dir, nlen);
+        cachefiles_hist(cachefiles_lookup_histogram, start);
+        if (IS_ERR(next))
+                goto lookup_error;
+
+        _debug("next -> %p %s", next, next->d_inode ? "positive" : "negative");
+
+        if (!key)
+                object->new = !next->d_inode;
+
+        /* if this element of the path doesn't exist, then the lookup phase
+         * failed, and we can release any readers in the certain knowledge that
+         * there's nothing for them to actually read */
+        if (!next->d_inode)
+                fscache_object_lookup_negative(&object->fscache);
+
+        /* we need to create the object if it's negative */
+        if (key || object->type == FSCACHE_COOKIE_TYPE_INDEX) {
+                /* index objects and intervening tree levels must be subdirs */
+                if (!next->d_inode) {
+                        ret = cachefiles_has_space(cache, 1, 0);
+                        if (ret < 0)
+                                goto create_error;
+
+                        start = jiffies;
+                        ret = vfs_mkdir(dir->d_inode, next, 0);
+                        cachefiles_hist(cachefiles_mkdir_histogram, start);
+                        if (ret < 0)
+                                goto create_error;
+
+                        ASSERT(next->d_inode);
+
+                        _debug("mkdir -> %p{%p{ino=%lu}}",
+                               next, next->d_inode, next->d_inode->i_ino);
+
+                } else if (!S_ISDIR(next->d_inode->i_mode)) {
+                        kerror("inode %lu is not a directory",
+                               next->d_inode->i_ino);
+                        ret = -ENOBUFS;
+                        goto error;
+                }
+
+        } else {
+                /* non-index objects start out life as files */
+                if (!next->d_inode) {
+                        ret = cachefiles_has_space(cache, 1, 0);
+                        if (ret < 0)
+                                goto create_error;
+
+                        start = jiffies;
+                        ret = vfs_create(dir->d_inode, next, S_IFREG, NULL);
+                        cachefiles_hist(cachefiles_create_histogram, start);
+                        if (ret < 0)
+                                goto create_error;
+
+                        ASSERT(next->d_inode);
+
+                        _debug("create -> %p{%p{ino=%lu}}",
+                               next, next->d_inode, next->d_inode->i_ino);
+
+                } else if (!S_ISDIR(next->d_inode->i_mode) &&
+                           !S_ISREG(next->d_inode->i_mode)
+                           ) {
+                        kerror("inode %lu is not a file or directory",
+                               next->d_inode->i_ino);
+                        ret = -ENOBUFS;
+                        goto error;
+                }
+        }
+
+        /* process the next component */
+        if (key) {
+                _debug("advance");
+                mutex_unlock(&dir->d_inode->i_mutex);
+                dput(dir);
+                dir = next;
+                next = NULL;
+                goto advance;
+        }
+
+        /* we've found the object we were looking for */
+        object->dentry = next;
+
+        /* if we've found that the terminal object exists, then we need to
+         * check its attributes and delete it if it's out of date */
+        if (!object->new) {
+                _debug("validate '%*.*s'",
+                       next->d_name.len, next->d_name.len, next->d_name.name);
+
+                ret = cachefiles_check_object_xattr(object, auxdata);
+                if (ret == -ESTALE) {
+                        /* delete the object (the deleter drops the directory
+                         * mutex) */
+                        object->dentry = NULL;
+
+                        ret = cachefiles_bury_object(cache, dir, next);
+                        dput(next);
+                        next = NULL;
+
+                        if (ret < 0)
+                                goto delete_error;
+
+                        _debug("redo lookup");
+                        goto lookup_again;
+                }
+        }
+
+        /* note that we're now using this object */
+        cachefiles_mark_object_active(cache, object);
+
+        mutex_unlock(&dir->d_inode->i_mutex);
+        dput(dir);
+        dir = NULL;
+
+        _debug("=== OBTAINED_OBJECT ===");
+
+        if (object->new) {
+                /* attach data to a newly constructed terminal object */
+                ret = cachefiles_set_object_xattr(object, auxdata);
+                if (ret < 0)
+                        goto check_error;
+        } else {
+                /* always update the atime on an object we've just looked up
+                 * (this is used to keep track of culling, and atimes are only
+                 * updated by read, write and readdir but not lookup or
+                 * open) */
+                touch_atime(cache->mnt, next);
+        }
+
+        /* open a file interface onto a data file */
+        if (object->type != FSCACHE_COOKIE_TYPE_INDEX) {
+                if (S_ISREG(object->dentry->d_inode->i_mode)) {
+                        const struct address_space_operations *aops;
+
+                        ret = -EPERM;
+                        aops = object->dentry->d_inode->i_mapping->a_ops;
+                        if (!aops->bmap)
+                                goto check_error;
+
+                        object->backer = object->dentry;
+                } else {
+                        BUG(); // TODO: open file in data-class subdir
+                }
+        }
+
+        object->new = 0;
+        fscache_obtained_object(&object->fscache);
+
+        _leave(" = 0 [%lu]", object->dentry->d_inode->i_ino);
+        return 0;
+
+create_error:
+        _debug("create error %d", ret);
+        if (ret == -EIO)
+                cachefiles_io_error(cache, "Create/mkdir failed");
+        goto error;
+
+check_error:
+        _debug("check error %d", ret);
+        write_lock(&cache->active_lock);
+        rb_erase(&object->active_node, &cache->active_nodes);
+        clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags);
+        wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
+        write_unlock(&cache->active_lock);
+
+        dput(object->dentry);
+        object->dentry = NULL;
+        goto error_out;
+
+delete_error:
+        _debug("delete error %d", ret);
+        goto error_out2;
+
+lookup_error:
+        _debug("lookup error %ld", PTR_ERR(next));
+        ret = PTR_ERR(next);
+        if (ret == -EIO)
+                cachefiles_io_error(cache, "Lookup failed");
+        next = NULL;
+error:
+        mutex_unlock(&dir->d_inode->i_mutex);
+        dput(next);
+error_out2:
+        dput(dir);
+error_out:
+        if (ret == -ENOSPC)
+                ret = -ENOBUFS;
+
+        _leave(" = error %d", -ret);
+        return ret;
+}
+
+/*
+ * get a subdirectory
+ */
+struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
+                                        struct dentry *dir,
+                                        const char *dirname)
+{
+        struct dentry *subdir;
+        unsigned long start;
+        int ret;
+
+        _enter(",,%s", dirname);
+
+        /* search the current directory for the element name */
+        mutex_lock(&dir->d_inode->i_mutex);
+
+        start = jiffies;
+        subdir = lookup_one_len(dirname, dir, strlen(dirname));
+        cachefiles_hist(cachefiles_lookup_histogram, start);
+        if (IS_ERR(subdir)) {
+                if (PTR_ERR(subdir) == -ENOMEM)
+                        goto nomem_d_alloc;
+                goto lookup_error;
+        }
+
+        _debug("subdir -> %p %s",
+               subdir, subdir->d_inode ? "positive" : "negative");
+
+        /* we need to create the subdir if it doesn't exist yet */
+        if (!subdir->d_inode) {
+                ret = cachefiles_has_space(cache, 1, 0);
+                if (ret < 0)
+                        goto mkdir_error;
+
+                _debug("attempt mkdir");
+
+                ret = vfs_mkdir(dir->d_inode, subdir, 0700);
+                if (ret < 0)
+                        goto mkdir_error;
+
+                ASSERT(subdir->d_inode);
+
+                _debug("mkdir -> %p{%p{ino=%lu}}",
+                       subdir,
+                       subdir->d_inode,
+                       subdir->d_inode->i_ino);
+        }
+
+        mutex_unlock(&dir->d_inode->i_mutex);
+
+        /* we need to make sure the subdir is a directory */
+        ASSERT(subdir->d_inode);
+
+        if (!S_ISDIR(subdir->d_inode->i_mode)) {
+                kerror("%s is not a directory", dirname);
+                ret = -EIO;
+                goto check_error;
+        }
+
+        ret = -EPERM;
+        if (!subdir->d_inode->i_op ||
+            !subdir->d_inode->i_op->setxattr ||
+            !subdir->d_inode->i_op->getxattr ||
+            !subdir->d_inode->i_op->lookup ||
+            !subdir->d_inode->i_op->mkdir ||
+            !subdir->d_inode->i_op->create ||
+            !subdir->d_inode->i_op->rename ||
+            !subdir->d_inode->i_op->rmdir ||
+            !subdir->d_inode->i_op->unlink)
+                goto check_error;
+
+        _leave(" = [%lu]", subdir->d_inode->i_ino);
+        return subdir;
+
+check_error:
+        dput(subdir);
+        _leave(" = %d [check]", ret);
+        return ERR_PTR(ret);
+
+mkdir_error:
+        mutex_unlock(&dir->d_inode->i_mutex);
+        dput(subdir);
+        kerror("mkdir %s failed with error %d", dirname, ret);
+        return ERR_PTR(ret);
+
+lookup_error:
+        mutex_unlock(&dir->d_inode->i_mutex);
+        ret = PTR_ERR(subdir);
+        kerror("Lookup %s failed with error %d", dirname, ret);
+        return ERR_PTR(ret);
+
+nomem_d_alloc:
+        mutex_unlock(&dir->d_inode->i_mutex);
+        _leave(" = -ENOMEM");
+        return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * find out if an object is in use or not
+ * - if finds object and it's not in use:
+ *   - returns a pointer to the object and a reference on it
+ *   - returns with the directory locked
+ */
+static struct dentry *cachefiles_check_active(struct cachefiles_cache *cache,
+                                              struct dentry *dir,
+                                              char *filename)
+{
+        struct cachefiles_object *object;
+        struct rb_node *_n;
+        struct dentry *victim;
+        unsigned long start;
+        int ret;
+
+        //_enter(",%*.*s/,%s",
+        //       dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
+
+        /* look up the victim */
+        mutex_lock_nested(&dir->d_inode->i_mutex, 1);
+
+        start = jiffies;
+        victim = lookup_one_len(filename, dir, strlen(filename));
+        cachefiles_hist(cachefiles_lookup_histogram, start);
+        if (IS_ERR(victim))
+                goto lookup_error;
+
+        //_debug("victim -> %p %s",
+        //       victim, victim->d_inode ? "positive" : "negative");
+
+        /* if the object is no longer there then we probably retired the object
+         * at the netfs's request whilst the cull was in progress
+         */
+        if (!victim->d_inode) {
+                mutex_unlock(&dir->d_inode->i_mutex);
+                dput(victim);
+                _leave(" = -ENOENT [absent]");
+                return ERR_PTR(-ENOENT);
+        }
+
+        /* check to see if we're using this object */
+        read_lock(&cache->active_lock);
+
+        _n = cache->active_nodes.rb_node;
+
+        while (_n) {
+                object = rb_entry(_n, struct cachefiles_object, active_node);
+
+                if (object->dentry > victim)
+                        _n = _n->rb_left;
+                else if (object->dentry < victim)
+                        _n = _n->rb_right;
+                else
+                        goto object_in_use;
+        }
+
+        read_unlock(&cache->active_lock);
+
+        //_leave(" = %p", victim);
+        return victim;
+
+object_in_use:
+        read_unlock(&cache->active_lock);
+        mutex_unlock(&dir->d_inode->i_mutex);
+        dput(victim);
+        //_leave(" = -EBUSY [in use]");
+        return ERR_PTR(-EBUSY);
+
+lookup_error:
+        mutex_unlock(&dir->d_inode->i_mutex);
+        ret = PTR_ERR(victim);
+        if (ret == -ENOENT) {
+                /* file or dir now absent - probably retired by netfs */
+                _leave(" = -ESTALE [absent]");
+                return ERR_PTR(-ESTALE);
+        }
+
+        if (ret == -EIO) {
+                cachefiles_io_error(cache, "Lookup failed");
+        } else if (ret != -ENOMEM) {
+                kerror("Internal error: %d", ret);
+                ret = -EIO;
+        }
+
+        _leave(" = %d", ret);
+        return ERR_PTR(ret);
+}
+
+/*
+ * cull an object if it's not in use
+ * - called only by cache manager daemon
+ */
+int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
+                    char *filename)
+{
+        struct dentry *victim;
+        int ret;
+
+        _enter(",%*.*s/,%s",
+               dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
+
+        victim = cachefiles_check_active(cache, dir, filename);
+        if (IS_ERR(victim))
+                return PTR_ERR(victim);
+
+        _debug("victim -> %p %s",
+               victim, victim->d_inode ? "positive" : "negative");
+
+        /* okay... the victim is not being used so we can cull it
+         * - start by marking it as stale
+         */
+        _debug("victim is cullable");
+
+        ret = cachefiles_remove_object_xattr(cache, victim);
+        if (ret < 0)
+                goto error_unlock;
+
+        /*  actually remove the victim (drops the dir mutex) */
+        _debug("bury");
+
+        ret = cachefiles_bury_object(cache, dir, victim);
+        if (ret < 0)
+                goto error;
+
+        dput(victim);
+        _leave(" = 0");
+        return 0;
+
+error_unlock:
+        mutex_unlock(&dir->d_inode->i_mutex);
+error:
+        dput(victim);
+        if (ret == -ENOENT) {
+                /* file or dir now absent - probably retired by netfs */
+                _leave(" = -ESTALE [absent]");
+                return -ESTALE;
+        }
+
+        if (ret != -ENOMEM) {
+                kerror("Internal error: %d", ret);
+                ret = -EIO;
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * find out if an object is in use or not
+ * - called only by cache manager daemon
+ * - returns -EBUSY or 0 to indicate whether an object is in use or not
+ */
+int cachefiles_check_in_use(struct cachefiles_cache *cache, struct dentry *dir,
+                            char *filename)
+{
+        struct dentry *victim;
+
+        //_enter(",%*.*s/,%s",
+        //       dir->d_name.len, dir->d_name.len, dir->d_name.name, filename);
+
+        victim = cachefiles_check_active(cache, dir, filename);
+        if (IS_ERR(victim))
+                return PTR_ERR(victim);
+
+        mutex_unlock(&dir->d_inode->i_mutex);
+        dput(victim);
+        //_leave(" = 0");
+        return 0;
+}
diff --git a/fs/cachefiles/proc.c b/fs/cachefiles/proc.c
new file mode 100644
index 000000000000..eccd33941199
--- /dev/null
+++ b/fs/cachefiles/proc.c
@@ -0,0 +1,134 @@
+/* CacheFiles statistics
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+atomic_t cachefiles_lookup_histogram[HZ];
+atomic_t cachefiles_mkdir_histogram[HZ];
+atomic_t cachefiles_create_histogram[HZ];
+
+/*
+ * display the latency histogram
+ */
+static int cachefiles_histogram_show(struct seq_file *m, void *v)
+{
+        unsigned long index;
+        unsigned x, y, z, t;
+
+        switch ((unsigned long) v) {
+        case 1:
+                seq_puts(m, "JIFS  SECS  LOOKUPS   MKDIRS    CREATES\n");
+                return 0;
+        case 2:
+                seq_puts(m, "===== ===== ========= ========= =========\n");
+                return 0;
+        default:
+                index = (unsigned long) v - 3;
+                x = atomic_read(&cachefiles_lookup_histogram[index]);
+                y = atomic_read(&cachefiles_mkdir_histogram[index]);
+                z = atomic_read(&cachefiles_create_histogram[index]);
+                if (x == 0 && y == 0 && z == 0)
+                        return 0;
+
+                t = (index * 1000) / HZ;
+
+                seq_printf(m, "%4lu  0.%03u %9u %9u %9u\n", index, t, x, y, z);
+                return 0;
+        }
+}
+
+/*
+ * set up the iterator to start reading from the first line
+ */
+static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos)
+{
+        if ((unsigned long long)*_pos >= HZ + 2)
+                return NULL;
+        if (*_pos == 0)
+                *_pos = 1;
+        return (void *)(unsigned long) *_pos;
+}
+
+/*
+ * move to the next line
+ */
+static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        (*pos)++;
+        return (unsigned long long)*pos > HZ + 2 ?
+                NULL : (void *)(unsigned long) *pos;
+}
+
+/*
+ * clean up after reading
+ */
+static void cachefiles_histogram_stop(struct seq_file *m, void *v)
+{
+}
+
+static const struct seq_operations cachefiles_histogram_ops = {
+        .start          = cachefiles_histogram_start,
+        .stop           = cachefiles_histogram_stop,
+        .next           = cachefiles_histogram_next,
+        .show           = cachefiles_histogram_show,
+};
+
+/*
+ * open "/proc/fs/cachefiles/XXX" which provide statistics summaries
+ */
+static int cachefiles_histogram_open(struct inode *inode, struct file *file)
+{
+        return seq_open(file, &cachefiles_histogram_ops);
+}
+
+static const struct file_operations cachefiles_histogram_fops = {
+        .owner          = THIS_MODULE,
+        .open           = cachefiles_histogram_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = seq_release,
+};
+
+/*
+ * initialise the /proc/fs/cachefiles/ directory
+ */
+int __init cachefiles_proc_init(void)
+{
+        _enter("");
+
+        if (!proc_mkdir("fs/cachefiles", NULL))
+                goto error_dir;
+
+        if (!proc_create("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
+                         &cachefiles_histogram_fops))
+                goto error_histogram;
+
+        _leave(" = 0");
+        return 0;
+
+error_histogram:
+        remove_proc_entry("fs/cachefiles", NULL);
+error_dir:
+        _leave(" = -ENOMEM");
+        return -ENOMEM;
+}
+
+/*
+ * clean up the /proc/fs/cachefiles/ directory
+ */
+void cachefiles_proc_cleanup(void)
+{
+        remove_proc_entry("fs/cachefiles/histogram", NULL);
+        remove_proc_entry("fs/cachefiles", NULL);
+}
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
new file mode 100644
index 000000000000..a69787e7dd96
--- /dev/null
+++ b/fs/cachefiles/rdwr.c
@@ -0,0 +1,879 @@
+/* Storage object read/write
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/mount.h>
+#include <linux/file.h>
+#include "internal.h"
+
+/*
+ * detect wake up events generated by the unlocking of pages in which we're
+ * interested
+ * - we use this to detect read completion of backing pages
+ * - the caller holds the waitqueue lock
+ */
+static int cachefiles_read_waiter(wait_queue_t *wait, unsigned mode,
+                                  int sync, void *_key)
+{
+        struct cachefiles_one_read *monitor =
+                container_of(wait, struct cachefiles_one_read, monitor);
+        struct cachefiles_object *object;
+        struct wait_bit_key *key = _key;
+        struct page *page = wait->private;
+
+        ASSERT(key);
+
+        _enter("{%lu},%u,%d,{%p,%u}",
+               monitor->netfs_page->index, mode, sync,
+               key->flags, key->bit_nr);
+
+        if (key->flags != &page->flags ||
+            key->bit_nr != PG_locked)
+                return 0;
+
+        _debug("--- monitor %p %lx ---", page, page->flags);
+
+        if (!PageUptodate(page) && !PageError(page))
+                dump_stack();
+
+        /* remove from the waitqueue */
+        list_del(&wait->task_list);
+
+        /* move onto the action list and queue for FS-Cache thread pool */
+        ASSERT(monitor->op);
+
+        object = container_of(monitor->op->op.object,
+                              struct cachefiles_object, fscache);
+
+        spin_lock(&object->work_lock);
+        list_add_tail(&monitor->op_link, &monitor->op->to_do);
+        spin_unlock(&object->work_lock);
+
+        fscache_enqueue_retrieval(monitor->op);
+        return 0;
+}
+
+/*
+ * copy data from backing pages to netfs pages to complete a read operation
+ * - driven by FS-Cache's thread pool
+ */
+static void cachefiles_read_copier(struct fscache_operation *_op)
+{
+        struct cachefiles_one_read *monitor;
+        struct cachefiles_object *object;
+        struct fscache_retrieval *op;
+        struct pagevec pagevec;
+        int error, max;
+
+        op = container_of(_op, struct fscache_retrieval, op);
+        object = container_of(op->op.object,
+                              struct cachefiles_object, fscache);
+
+        _enter("{ino=%lu}", object->backer->d_inode->i_ino);
+
+        pagevec_init(&pagevec, 0);
+
+        max = 8;
+        spin_lock_irq(&object->work_lock);
+
+        while (!list_empty(&op->to_do)) {
+                monitor = list_entry(op->to_do.next,
+                                     struct cachefiles_one_read, op_link);
+                list_del(&monitor->op_link);
+
+                spin_unlock_irq(&object->work_lock);
+
+                _debug("- copy {%lu}", monitor->back_page->index);
+
+                error = -EIO;
+                if (PageUptodate(monitor->back_page)) {
+                        copy_highpage(monitor->netfs_page, monitor->back_page);
+
+                        pagevec_add(&pagevec, monitor->netfs_page);
+                        fscache_mark_pages_cached(monitor->op, &pagevec);
+                        error = 0;
+                }
+
+                if (error)
+                        cachefiles_io_error_obj(
+                                object,
+                                "Readpage failed on backing file %lx",
+                                (unsigned long) monitor->back_page->flags);
+
+                page_cache_release(monitor->back_page);
+
+                fscache_end_io(op, monitor->netfs_page, error);
+                page_cache_release(monitor->netfs_page);
+                fscache_put_retrieval(op);
+                kfree(monitor);
+
+                /* let the thread pool have some air occasionally */
+                max--;
+                if (max < 0 || need_resched()) {
+                        if (!list_empty(&op->to_do))
+                                fscache_enqueue_retrieval(op);
+                        _leave(" [maxed out]");
+                        return;
+                }
+
+                spin_lock_irq(&object->work_lock);
+        }
+
+        spin_unlock_irq(&object->work_lock);
+        _leave("");
+}
+
+/*
+ * read the corresponding page to the given set from the backing file
+ * - an uncertain page is simply discarded, to be tried again another time
+ */
+static int cachefiles_read_backing_file_one(struct cachefiles_object *object,
+                                            struct fscache_retrieval *op,
+                                            struct page *netpage,
+                                            struct pagevec *pagevec)
+{
+        struct cachefiles_one_read *monitor;
+        struct address_space *bmapping;
+        struct page *newpage, *backpage;
+        int ret;
+
+        _enter("");
+
+        pagevec_reinit(pagevec);
+
+        _debug("read back %p{%lu,%d}",
+               netpage, netpage->index, page_count(netpage));
+
+        monitor = kzalloc(sizeof(*monitor), GFP_KERNEL);
+        if (!monitor)
+                goto nomem;
+
+        monitor->netfs_page = netpage;
+        monitor->op = fscache_get_retrieval(op);
+
+        init_waitqueue_func_entry(&monitor->monitor, cachefiles_read_waiter);
+
+        /* attempt to get hold of the backing page */
+        bmapping = object->backer->d_inode->i_mapping;
+        newpage = NULL;
+
+        for (;;) {
+                backpage = find_get_page(bmapping, netpage->index);
+                if (backpage)
+                        goto backing_page_already_present;
+
+                if (!newpage) {
+                        newpage = page_cache_alloc_cold(bmapping);
+                        if (!newpage)
+                                goto nomem_monitor;
+                }
+
+                ret = add_to_page_cache(newpage, bmapping,
+                                        netpage->index, GFP_KERNEL);
+                if (ret == 0)
+                        goto installed_new_backing_page;
+                if (ret != -EEXIST)
+                        goto nomem_page;
+        }
+
+        /* we've installed a new backing page, so now we need to add it
+         * to the LRU list and start it reading */
+installed_new_backing_page:
+        _debug("- new %p", newpage);
+
+        backpage = newpage;
+        newpage = NULL;
+
+        page_cache_get(backpage);
+        pagevec_add(pagevec, backpage);
+        __pagevec_lru_add_file(pagevec);
+
+read_backing_page:
+        ret = bmapping->a_ops->readpage(NULL, backpage);
+        if (ret < 0)
+                goto read_error;
+
+        /* set the monitor to transfer the data across */
+monitor_backing_page:
+        _debug("- monitor add");
+
+        /* install the monitor */
+        page_cache_get(monitor->netfs_page);
+        page_cache_get(backpage);
+        monitor->back_page = backpage;
+        monitor->monitor.private = backpage;
+        add_page_wait_queue(backpage, &monitor->monitor);
+        monitor = NULL;
+
+        /* but the page may have been read before the monitor was installed, so
+         * the monitor may miss the event - so we have to ensure that we do get
+         * one in such a case */
+        if (trylock_page(backpage)) {
+                _debug("jumpstart %p {%lx}", backpage, backpage->flags);
+                unlock_page(backpage);
+        }
+        goto success;
+
+        /* if the backing page is already present, it can be in one of
+         * three states: read in progress, read failed or read okay */
+backing_page_already_present:
+        _debug("- present");
+
+        if (newpage) {
+                page_cache_release(newpage);
+                newpage = NULL;
+        }
+
+        if (PageError(backpage))
+                goto io_error;
+
+        if (PageUptodate(backpage))
+                goto backing_page_already_uptodate;
+
+        if (!trylock_page(backpage))
+                goto monitor_backing_page;
+        _debug("read %p {%lx}", backpage, backpage->flags);
+        goto read_backing_page;
+
+        /* the backing page is already up to date, attach the netfs
+         * page to the pagecache and LRU and copy the data across */
+backing_page_already_uptodate:
+        _debug("- uptodate");
+
+        pagevec_add(pagevec, netpage);
+        fscache_mark_pages_cached(op, pagevec);
+
+        copy_highpage(netpage, backpage);
+        fscache_end_io(op, netpage, 0);
+
+success:
+        _debug("success");
+        ret = 0;
+
+out:
+        if (backpage)
+                page_cache_release(backpage);
+        if (monitor) {
+                fscache_put_retrieval(monitor->op);
+                kfree(monitor);
+        }
+        _leave(" = %d", ret);
+        return ret;
+
+read_error:
+        _debug("read error %d", ret);
+        if (ret == -ENOMEM)
+                goto out;
+io_error:
+        cachefiles_io_error_obj(object, "Page read error on backing file");
+        ret = -ENOBUFS;
+        goto out;
+
+nomem_page:
+        page_cache_release(newpage);
+nomem_monitor:
+        fscache_put_retrieval(monitor->op);
+        kfree(monitor);
+nomem:
+        _leave(" = -ENOMEM");
+        return -ENOMEM;
+}
+
+/*
+ * read a page from the cache or allocate a block in which to store it
+ * - cache withdrawal is prevented by the caller
+ * - returns -EINTR if interrupted
+ * - returns -ENOMEM if ran out of memory
+ * - returns -ENOBUFS if no buffers can be made available
+ * - returns -ENOBUFS if page is beyond EOF
+ * - if the page is backed by a block in the cache:
+ *   - a read will be started which will call the callback on completion
+ *   - 0 will be returned
+ * - else if the page is unbacked:
+ *   - the metadata will be retained
+ *   - -ENODATA will be returned
+ */
+int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
+                                  struct page *page,
+                                  gfp_t gfp)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        struct pagevec pagevec;
+        struct inode *inode;
+        sector_t block0, block;
+        unsigned shift;
+        int ret;
+
+        object = container_of(op->op.object,
+                              struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        _enter("{%p},{%lx},,,", object, page->index);
+
+        if (!object->backer)
+                return -ENOBUFS;
+
+        inode = object->backer->d_inode;
+        ASSERT(S_ISREG(inode->i_mode));
+        ASSERT(inode->i_mapping->a_ops->bmap);
+        ASSERT(inode->i_mapping->a_ops->readpages);
+
+        /* calculate the shift required to use bmap */
+        if (inode->i_sb->s_blocksize > PAGE_SIZE)
+                return -ENOBUFS;
+
+        shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
+
+        op->op.flags = FSCACHE_OP_FAST;
+        op->op.processor = cachefiles_read_copier;
+
+        pagevec_init(&pagevec, 0);
+
+        /* we assume the absence or presence of the first block is a good
+         * enough indication for the page as a whole
+         * - TODO: don't use bmap() for this as it is _not_ actually good
+         *   enough for this as it doesn't indicate errors, but it's all we've
+         *   got for the moment
+         */
+        block0 = page->index;
+        block0 <<= shift;
+
+        block = inode->i_mapping->a_ops->bmap(inode->i_mapping, block0);
+        _debug("%llx -> %llx",
+               (unsigned long long) block0,
+               (unsigned long long) block);
+
+        if (block) {
+                /* submit the apparently valid page to the backing fs to be
+                 * read from disk */
+                ret = cachefiles_read_backing_file_one(object, op, page,
+                                                       &pagevec);
+        } else if (cachefiles_has_space(cache, 0, 1) == 0) {
+                /* there's space in the cache we can use */
+                pagevec_add(&pagevec, page);
+                fscache_mark_pages_cached(op, &pagevec);
+                ret = -ENODATA;
+        } else {
+                ret = -ENOBUFS;
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * read the corresponding pages to the given set from the backing file
+ * - any uncertain pages are simply discarded, to be tried again another time
+ */
+static int cachefiles_read_backing_file(struct cachefiles_object *object,
+                                        struct fscache_retrieval *op,
+                                        struct list_head *list,
+                                        struct pagevec *mark_pvec)
+{
+        struct cachefiles_one_read *monitor = NULL;
+        struct address_space *bmapping = object->backer->d_inode->i_mapping;
+        struct pagevec lru_pvec;
+        struct page *newpage = NULL, *netpage, *_n, *backpage = NULL;
+        int ret = 0;
+
+        _enter("");
+
+        pagevec_init(&lru_pvec, 0);
+
+        list_for_each_entry_safe(netpage, _n, list, lru) {
+                list_del(&netpage->lru);
+
+                _debug("read back %p{%lu,%d}",
+                       netpage, netpage->index, page_count(netpage));
+
+                if (!monitor) {
+                        monitor = kzalloc(sizeof(*monitor), GFP_KERNEL);
+                        if (!monitor)
+                                goto nomem;
+
+                        monitor->op = fscache_get_retrieval(op);
+                        init_waitqueue_func_entry(&monitor->monitor,
+                                                  cachefiles_read_waiter);
+                }
+
+                for (;;) {
+                        backpage = find_get_page(bmapping, netpage->index);
+                        if (backpage)
+                                goto backing_page_already_present;
+
+                        if (!newpage) {
+                                newpage = page_cache_alloc_cold(bmapping);
+                                if (!newpage)
+                                        goto nomem;
+                        }
+
+                        ret = add_to_page_cache(newpage, bmapping,
+                                                netpage->index, GFP_KERNEL);
+                        if (ret == 0)
+                                goto installed_new_backing_page;
+                        if (ret != -EEXIST)
+                                goto nomem;
+                }
+
+                /* we've installed a new backing page, so now we need to add it
+                 * to the LRU list and start it reading */
+        installed_new_backing_page:
+                _debug("- new %p", newpage);
+
+                backpage = newpage;
+                newpage = NULL;
+
+                page_cache_get(backpage);
+                if (!pagevec_add(&lru_pvec, backpage))
+                        __pagevec_lru_add_file(&lru_pvec);
+
+        reread_backing_page:
+                ret = bmapping->a_ops->readpage(NULL, backpage);
+                if (ret < 0)
+                        goto read_error;
+
+                /* add the netfs page to the pagecache and LRU, and set the
+                 * monitor to transfer the data across */
+        monitor_backing_page:
+                _debug("- monitor add");
+
+                ret = add_to_page_cache(netpage, op->mapping, netpage->index,
+                                        GFP_KERNEL);
+                if (ret < 0) {
+                        if (ret == -EEXIST) {
+                                page_cache_release(netpage);
+                                continue;
+                        }
+                        goto nomem;
+                }
+
+                page_cache_get(netpage);
+                if (!pagevec_add(&lru_pvec, netpage))
+                        __pagevec_lru_add_file(&lru_pvec);
+
+                /* install a monitor */
+                page_cache_get(netpage);
+                monitor->netfs_page = netpage;
+
+                page_cache_get(backpage);
+                monitor->back_page = backpage;
+                monitor->monitor.private = backpage;
+                add_page_wait_queue(backpage, &monitor->monitor);
+                monitor = NULL;
+
+                /* but the page may have been read before the monitor was
+                 * installed, so the monitor may miss the event - so we have to
+                 * ensure that we do get one in such a case */
+                if (trylock_page(backpage)) {
+                        _debug("2unlock %p {%lx}", backpage, backpage->flags);
+                        unlock_page(backpage);
+                }
+
+                page_cache_release(backpage);
+                backpage = NULL;
+
+                page_cache_release(netpage);
+                netpage = NULL;
+                continue;
+
+                /* if the backing page is already present, it can be in one of
+                 * three states: read in progress, read failed or read okay */
+        backing_page_already_present:
+                _debug("- present %p", backpage);
+
+                if (PageError(backpage))
+                        goto io_error;
+
+                if (PageUptodate(backpage))
+                        goto backing_page_already_uptodate;
+
+                _debug("- not ready %p{%lx}", backpage, backpage->flags);
+
+                if (!trylock_page(backpage))
+                        goto monitor_backing_page;
+
+                if (PageError(backpage)) {
+                        _debug("error %lx", backpage->flags);
+                        unlock_page(backpage);
+                        goto io_error;
+                }
+
+                if (PageUptodate(backpage))
+                        goto backing_page_already_uptodate_unlock;
+
+                /* we've locked a page that's neither up to date nor erroneous,
+                 * so we need to attempt to read it again */
+                goto reread_backing_page;
+
+                /* the backing page is already up to date, attach the netfs
+                 * page to the pagecache and LRU and copy the data across */
+        backing_page_already_uptodate_unlock:
+                _debug("uptodate %lx", backpage->flags);
+                unlock_page(backpage);
+        backing_page_already_uptodate:
+                _debug("- uptodate");
+
+                ret = add_to_page_cache(netpage, op->mapping, netpage->index,
+                                        GFP_KERNEL);
+                if (ret < 0) {
+                        if (ret == -EEXIST) {
+                                page_cache_release(netpage);
+                                continue;
+                        }
+                        goto nomem;
+                }
+
+                copy_highpage(netpage, backpage);
+
+                page_cache_release(backpage);
+                backpage = NULL;
+
+                if (!pagevec_add(mark_pvec, netpage))
+                        fscache_mark_pages_cached(op, mark_pvec);
+
+                page_cache_get(netpage);
+                if (!pagevec_add(&lru_pvec, netpage))
+                        __pagevec_lru_add_file(&lru_pvec);
+
+                fscache_end_io(op, netpage, 0);
+                page_cache_release(netpage);
+                netpage = NULL;
+                continue;
+        }
+
+        netpage = NULL;
+
+        _debug("out");
+
+out:
+        /* tidy up */
+        pagevec_lru_add_file(&lru_pvec);
+
+        if (newpage)
+                page_cache_release(newpage);
+        if (netpage)
+                page_cache_release(netpage);
+        if (backpage)
+                page_cache_release(backpage);
+        if (monitor) {
+                fscache_put_retrieval(op);
+                kfree(monitor);
+        }
+
+        list_for_each_entry_safe(netpage, _n, list, lru) {
+                list_del(&netpage->lru);
+                page_cache_release(netpage);
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+
+nomem:
+        _debug("nomem");
+        ret = -ENOMEM;
+        goto out;
+
+read_error:
+        _debug("read error %d", ret);
+        if (ret == -ENOMEM)
+                goto out;
+io_error:
+        cachefiles_io_error_obj(object, "Page read error on backing file");
+        ret = -ENOBUFS;
+        goto out;
+}
+
+/*
+ * read a list of pages from the cache or allocate blocks in which to store
+ * them
+ */
+int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
+                                   struct list_head *pages,
+                                   unsigned *nr_pages,
+                                   gfp_t gfp)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        struct list_head backpages;
+        struct pagevec pagevec;
+        struct inode *inode;
+        struct page *page, *_n;
+        unsigned shift, nrbackpages;
+        int ret, ret2, space;
+
+        object = container_of(op->op.object,
+                              struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        _enter("{OBJ%x,%d},,%d,,",
+               object->fscache.debug_id, atomic_read(&op->op.usage),
+               *nr_pages);
+
+        if (!object->backer)
+                return -ENOBUFS;
+
+        space = 1;
+        if (cachefiles_has_space(cache, 0, *nr_pages) < 0)
+                space = 0;
+
+        inode = object->backer->d_inode;
+        ASSERT(S_ISREG(inode->i_mode));
+        ASSERT(inode->i_mapping->a_ops->bmap);
+        ASSERT(inode->i_mapping->a_ops->readpages);
+
+        /* calculate the shift required to use bmap */
+        if (inode->i_sb->s_blocksize > PAGE_SIZE)
+                return -ENOBUFS;
+
+        shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
+
+        pagevec_init(&pagevec, 0);
+
+        op->op.flags = FSCACHE_OP_FAST;
+        op->op.processor = cachefiles_read_copier;
+
+        INIT_LIST_HEAD(&backpages);
+        nrbackpages = 0;
+
+        ret = space ? -ENODATA : -ENOBUFS;
+        list_for_each_entry_safe(page, _n, pages, lru) {
+                sector_t block0, block;
+
+                /* we assume the absence or presence of the first block is a
+                 * good enough indication for the page as a whole
+                 * - TODO: don't use bmap() for this as it is _not_ actually
+                 *   good enough for this as it doesn't indicate errors, but
+                 *   it's all we've got for the moment
+                 */
+                block0 = page->index;
+                block0 <<= shift;
+
+                block = inode->i_mapping->a_ops->bmap(inode->i_mapping,
+                                                      block0);
+                _debug("%llx -> %llx",
+                       (unsigned long long) block0,
+                       (unsigned long long) block);
+
+                if (block) {
+                        /* we have data - add it to the list to give to the
+                         * backing fs */
+                        list_move(&page->lru, &backpages);
+                        (*nr_pages)--;
+                        nrbackpages++;
+                } else if (space && pagevec_add(&pagevec, page) == 0) {
+                        fscache_mark_pages_cached(op, &pagevec);
+                        ret = -ENODATA;
+                }
+        }
+
+        if (pagevec_count(&pagevec) > 0)
+                fscache_mark_pages_cached(op, &pagevec);
+
+        if (list_empty(pages))
+                ret = 0;
+
+        /* submit the apparently valid pages to the backing fs to be read from
+         * disk */
+        if (nrbackpages > 0) {
+                ret2 = cachefiles_read_backing_file(object, op, &backpages,
+                                                    &pagevec);
+                if (ret2 == -ENOMEM || ret2 == -EINTR)
+                        ret = ret2;
+        }
+
+        if (pagevec_count(&pagevec) > 0)
+                fscache_mark_pages_cached(op, &pagevec);
+
+        _leave(" = %d [nr=%u%s]",
+               ret, *nr_pages, list_empty(pages) ? " empty" : "");
+        return ret;
+}
+
+/*
+ * allocate a block in the cache in which to store a page
+ * - cache withdrawal is prevented by the caller
+ * - returns -EINTR if interrupted
+ * - returns -ENOMEM if ran out of memory
+ * - returns -ENOBUFS if no buffers can be made available
+ * - returns -ENOBUFS if page is beyond EOF
+ * - otherwise:
+ *   - the metadata will be retained
+ *   - 0 will be returned
+ */
+int cachefiles_allocate_page(struct fscache_retrieval *op,
+                             struct page *page,
+                             gfp_t gfp)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        struct pagevec pagevec;
+        int ret;
+
+        object = container_of(op->op.object,
+                              struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        _enter("%p,{%lx},", object, page->index);
+
+        ret = cachefiles_has_space(cache, 0, 1);
+        if (ret == 0) {
+                pagevec_init(&pagevec, 0);
+                pagevec_add(&pagevec, page);
+                fscache_mark_pages_cached(op, &pagevec);
+        } else {
+                ret = -ENOBUFS;
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * allocate blocks in the cache in which to store a set of pages
+ * - cache withdrawal is prevented by the caller
+ * - returns -EINTR if interrupted
+ * - returns -ENOMEM if ran out of memory
+ * - returns -ENOBUFS if some buffers couldn't be made available
+ * - returns -ENOBUFS if some pages are beyond EOF
+ * - otherwise:
+ *   - -ENODATA will be returned
+ * - metadata will be retained for any page marked
+ */
+int cachefiles_allocate_pages(struct fscache_retrieval *op,
+                              struct list_head *pages,
+                              unsigned *nr_pages,
+                              gfp_t gfp)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        struct pagevec pagevec;
+        struct page *page;
+        int ret;
+
+        object = container_of(op->op.object,
+                              struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        _enter("%p,,,%d,", object, *nr_pages);
+
+        ret = cachefiles_has_space(cache, 0, *nr_pages);
+        if (ret == 0) {
+                pagevec_init(&pagevec, 0);
+
+                list_for_each_entry(page, pages, lru) {
+                        if (pagevec_add(&pagevec, page) == 0)
+                                fscache_mark_pages_cached(op, &pagevec);
+                }
+
+                if (pagevec_count(&pagevec) > 0)
+                        fscache_mark_pages_cached(op, &pagevec);
+                ret = -ENODATA;
+        } else {
+                ret = -ENOBUFS;
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * request a page be stored in the cache
+ * - cache withdrawal is prevented by the caller
+ * - this request may be ignored if there's no cache block available, in which
+ *   case -ENOBUFS will be returned
+ * - if the op is in progress, 0 will be returned
+ */
+int cachefiles_write_page(struct fscache_storage *op, struct page *page)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+        mm_segment_t old_fs;
+        struct file *file;
+        loff_t pos;
+        void *data;
+        int ret;
+
+        ASSERT(op != NULL);
+        ASSERT(page != NULL);
+
+        object = container_of(op->op.object,
+                              struct cachefiles_object, fscache);
+
+        _enter("%p,%p{%lx},,,", object, page, page->index);
+
+        if (!object->backer) {
+                _leave(" = -ENOBUFS");
+                return -ENOBUFS;
+        }
+
+        ASSERT(S_ISREG(object->backer->d_inode->i_mode));
+
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        /* write the page to the backing filesystem and let it store it in its
+         * own time */
+        dget(object->backer);
+        mntget(cache->mnt);
+        file = dentry_open(object->backer, cache->mnt, O_RDWR,
+                           cache->cache_cred);
+        if (IS_ERR(file)) {
+                ret = PTR_ERR(file);
+        } else {
+                ret = -EIO;
+                if (file->f_op->write) {
+                        pos = (loff_t) page->index << PAGE_SHIFT;
+                        data = kmap(page);
+                        old_fs = get_fs();
+                        set_fs(KERNEL_DS);
+                        ret = file->f_op->write(
+                                file, (const void __user *) data, PAGE_SIZE,
+                                &pos);
+                        set_fs(old_fs);
+                        kunmap(page);
+                        if (ret != PAGE_SIZE)
+                                ret = -EIO;
+                }
+                fput(file);
+        }
+
+        if (ret < 0) {
+                if (ret == -EIO)
+                        cachefiles_io_error_obj(
+                                object, "Write page to backing file failed");
+                ret = -ENOBUFS;
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * detach a backing block from a page
+ * - cache withdrawal is prevented by the caller
+ */
+void cachefiles_uncache_page(struct fscache_object *_object, struct page *page)
+{
+        struct cachefiles_object *object;
+        struct cachefiles_cache *cache;
+
+        object = container_of(_object, struct cachefiles_object, fscache);
+        cache = container_of(object->fscache.cache,
+                             struct cachefiles_cache, cache);
+
+        _enter("%p,{%lu}", object, page->index);
+
+        spin_unlock(&object->fscache.cookie->lock);
+}
diff --git a/fs/cachefiles/security.c b/fs/cachefiles/security.c
new file mode 100644
index 000000000000..b5808cdb2232
--- /dev/null
+++ b/fs/cachefiles/security.c
@@ -0,0 +1,116 @@
+/* CacheFiles security management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/fs.h>
+#include <linux/cred.h>
+#include "internal.h"
+
+/*
+ * determine the security context within which we access the cache from within
+ * the kernel
+ */
+int cachefiles_get_security_ID(struct cachefiles_cache *cache)
+{
+        struct cred *new;
+        int ret;
+
+        _enter("{%s}", cache->secctx);
+
+        new = prepare_kernel_cred(current);
+        if (!new) {
+                ret = -ENOMEM;
+                goto error;
+        }
+
+        if (cache->secctx) {
+                ret = set_security_override_from_ctx(new, cache->secctx);
+                if (ret < 0) {
+                        put_cred(new);
+                        printk(KERN_ERR "CacheFiles:"
+                               " Security denies permission to nominate"
+                               " security context: error %d\n",
+                               ret);
+                        goto error;
+                }
+        }
+
+        cache->cache_cred = new;
+        ret = 0;
+error:
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * see if mkdir and create can be performed in the root directory
+ */
+static int cachefiles_check_cache_dir(struct cachefiles_cache *cache,
+                                      struct dentry *root)
+{
+        int ret;
+
+        ret = security_inode_mkdir(root->d_inode, root, 0);
+        if (ret < 0) {
+                printk(KERN_ERR "CacheFiles:"
+                       " Security denies permission to make dirs: error %d",
+                       ret);
+                return ret;
+        }
+
+        ret = security_inode_create(root->d_inode, root, 0);
+        if (ret < 0)
+                printk(KERN_ERR "CacheFiles:"
+                       " Security denies permission to create files: error %d",
+                       ret);
+
+        return ret;
+}
+
+/*
+ * check the security details of the on-disk cache
+ * - must be called with security override in force
+ */
+int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
+                                        struct dentry *root,
+                                        const struct cred **_saved_cred)
+{
+        struct cred *new;
+        int ret;
+
+        _enter("");
+
+        /* duplicate the cache creds for COW (the override is currently in
+         * force, so we can use prepare_creds() to do this) */
+        new = prepare_creds();
+        if (!new)
+                return -ENOMEM;
+
+        cachefiles_end_secure(cache, *_saved_cred);
+
+        /* use the cache root dir's security context as the basis with
+         * which create files */
+        ret = set_create_files_as(new, root->d_inode);
+        if (ret < 0) {
+                _leave(" = %d [cfa]", ret);
+                return ret;
+        }
+
+        put_cred(cache->cache_cred);
+        cache->cache_cred = new;
+
+        cachefiles_begin_secure(cache, _saved_cred);
+        ret = cachefiles_check_cache_dir(cache, root);
+
+        if (ret == -EOPNOTSUPP)
+                ret = 0;
+        _leave(" = %d", ret);
+        return ret;
+}
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
new file mode 100644
index 000000000000..f3e7a0bf068b
--- /dev/null
+++ b/fs/cachefiles/xattr.c
@@ -0,0 +1,291 @@
+/* CacheFiles extended attribute management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/xattr.h>
+#include "internal.h"
+
+static const char cachefiles_xattr_cache[] =
+        XATTR_USER_PREFIX "CacheFiles.cache";
+
+/*
+ * check the type label on an object
+ * - done using xattrs
+ */
+int cachefiles_check_object_type(struct cachefiles_object *object)
+{
+        struct dentry *dentry = object->dentry;
+        char type[3], xtype[3];
+        int ret;
+
+        ASSERT(dentry);
+        ASSERT(dentry->d_inode);
+
+        if (!object->fscache.cookie)
+                strcpy(type, "C3");
+        else
+                snprintf(type, 3, "%02x", object->fscache.cookie->def->type);
+
+        _enter("%p{%s}", object, type);
+
+        /* attempt to install a type label directly */
+        ret = vfs_setxattr(dentry, cachefiles_xattr_cache, type, 2,
+                           XATTR_CREATE);
+        if (ret == 0) {
+                _debug("SET"); /* we succeeded */
+                goto error;
+        }
+
+        if (ret != -EEXIST) {
+                kerror("Can't set xattr on %*.*s [%lu] (err %d)",
+                       dentry->d_name.len, dentry->d_name.len,
+                       dentry->d_name.name, dentry->d_inode->i_ino,
+                       -ret);
+                goto error;
+        }
+
+        /* read the current type label */
+        ret = vfs_getxattr(dentry, cachefiles_xattr_cache, xtype, 3);
+        if (ret < 0) {
+                if (ret == -ERANGE)
+                        goto bad_type_length;
+
+                kerror("Can't read xattr on %*.*s [%lu] (err %d)",
+                       dentry->d_name.len, dentry->d_name.len,
+                       dentry->d_name.name, dentry->d_inode->i_ino,
+                       -ret);
+                goto error;
+        }
+
+        /* check the type is what we're expecting */
+        if (ret != 2)
+                goto bad_type_length;
+
+        if (xtype[0] != type[0] || xtype[1] != type[1])
+                goto bad_type;
+
+        ret = 0;
+
+error:
+        _leave(" = %d", ret);
+        return ret;
+
+bad_type_length:
+        kerror("Cache object %lu type xattr length incorrect",
+               dentry->d_inode->i_ino);
+        ret = -EIO;
+        goto error;
+
+bad_type:
+        xtype[2] = 0;
+        kerror("Cache object %*.*s [%lu] type %s not %s",
+               dentry->d_name.len, dentry->d_name.len,
+               dentry->d_name.name, dentry->d_inode->i_ino,
+               xtype, type);
+        ret = -EIO;
+        goto error;
+}
+
+/*
+ * set the state xattr on a cache file
+ */
+int cachefiles_set_object_xattr(struct cachefiles_object *object,
+                                struct cachefiles_xattr *auxdata)
+{
+        struct dentry *dentry = object->dentry;
+        int ret;
+
+        ASSERT(object->fscache.cookie);
+        ASSERT(dentry);
+
+        _enter("%p,#%d", object, auxdata->len);
+
+        /* attempt to install the cache metadata directly */
+        _debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
+
+        ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
+                           &auxdata->type, auxdata->len,
+                           XATTR_CREATE);
+        if (ret < 0 && ret != -ENOMEM)
+                cachefiles_io_error_obj(
+                        object,
+                        "Failed to set xattr with error %d", ret);
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * update the state xattr on a cache file
+ */
+int cachefiles_update_object_xattr(struct cachefiles_object *object,
+                                   struct cachefiles_xattr *auxdata)
+{
+        struct dentry *dentry = object->dentry;
+        int ret;
+
+        ASSERT(object->fscache.cookie);
+        ASSERT(dentry);
+
+        _enter("%p,#%d", object, auxdata->len);
+
+        /* attempt to install the cache metadata directly */
+        _debug("SET %s #%u", object->fscache.cookie->def->name, auxdata->len);
+
+        ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
+                           &auxdata->type, auxdata->len,
+                           XATTR_REPLACE);
+        if (ret < 0 && ret != -ENOMEM)
+                cachefiles_io_error_obj(
+                        object,
+                        "Failed to update xattr with error %d", ret);
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * check the state xattr on a cache file
+ * - return -ESTALE if the object should be deleted
+ */
+int cachefiles_check_object_xattr(struct cachefiles_object *object,
+                                  struct cachefiles_xattr *auxdata)
+{
+        struct cachefiles_xattr *auxbuf;
+        struct dentry *dentry = object->dentry;
+        int ret;
+
+        _enter("%p,#%d", object, auxdata->len);
+
+        ASSERT(dentry);
+        ASSERT(dentry->d_inode);
+
+        auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
+        if (!auxbuf) {
+                _leave(" = -ENOMEM");
+                return -ENOMEM;
+        }
+
+        /* read the current type label */
+        ret = vfs_getxattr(dentry, cachefiles_xattr_cache,
+                           &auxbuf->type, 512 + 1);
+        if (ret < 0) {
+                if (ret == -ENODATA)
+                        goto stale; /* no attribute - power went off
+                                     * mid-cull? */
+
+                if (ret == -ERANGE)
+                        goto bad_type_length;
+
+                cachefiles_io_error_obj(object,
+                                        "Can't read xattr on %lu (err %d)",
+                                        dentry->d_inode->i_ino, -ret);
+                goto error;
+        }
+
+        /* check the on-disk object */
+        if (ret < 1)
+                goto bad_type_length;
+
+        if (auxbuf->type != auxdata->type)
+                goto stale;
+
+        auxbuf->len = ret;
+
+        /* consult the netfs */
+        if (object->fscache.cookie->def->check_aux) {
+                enum fscache_checkaux result;
+                unsigned int dlen;
+
+                dlen = auxbuf->len - 1;
+
+                _debug("checkaux %s #%u",
+                       object->fscache.cookie->def->name, dlen);
+
+                result = fscache_check_aux(&object->fscache,
+                                           &auxbuf->data, dlen);
+
+                switch (result) {
+                        /* entry okay as is */
+                case FSCACHE_CHECKAUX_OKAY:
+                        goto okay;
+
+                        /* entry requires update */
+                case FSCACHE_CHECKAUX_NEEDS_UPDATE:
+                        break;
+
+                        /* entry requires deletion */
+                case FSCACHE_CHECKAUX_OBSOLETE:
+                        goto stale;
+
+                default:
+                        BUG();
+                }
+
+                /* update the current label */
+                ret = vfs_setxattr(dentry, cachefiles_xattr_cache,
+                                   &auxdata->type, auxdata->len,
+                                   XATTR_REPLACE);
+                if (ret < 0) {
+                        cachefiles_io_error_obj(object,
+                                                "Can't update xattr on %lu"
+                                                " (error %d)",
+                                                dentry->d_inode->i_ino, -ret);
+                        goto error;
+                }
+        }
+
+okay:
+        ret = 0;
+
+error:
+        kfree(auxbuf);
+        _leave(" = %d", ret);
+        return ret;
+
+bad_type_length:
+        kerror("Cache object %lu xattr length incorrect",
+               dentry->d_inode->i_ino);
+        ret = -EIO;
+        goto error;
+
+stale:
+        ret = -ESTALE;
+        goto error;
+}
+
+/*
+ * remove the object's xattr to mark it stale
+ */
+int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
+                                   struct dentry *dentry)
+{
+        int ret;
+
+        ret = vfs_removexattr(dentry, cachefiles_xattr_cache);
+        if (ret < 0) {
+                if (ret == -ENOENT || ret == -ENODATA)
+                        ret = 0;
+                else if (ret != -ENOMEM)
+                        cachefiles_io_error(cache,
+                                            "Can't remove xattr from %lu"
+                                            " (error %d)",
+                                            dentry->d_inode->i_ino, -ret);
+        }
+
+        _leave(" = %d", ret);
+        return ret;
+}