9 files changed, 241 insertions, 37 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 23d2f4460deb..cfbfa15a46ba 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -394,11 +394,10 @@ prototypes:
         unsigned long (*get_unmapped_area)(struct file *, unsigned long,
                         unsigned long, unsigned long, unsigned long);
         int (*check_flags)(int);
-        int (*dir_notify)(struct file *, unsigned long);
 };
 
 locking rules:
-        All except ->poll() may block.
+        All may block.
                         BKL
 llseek:                 no      (see below)
 read:                   no
@@ -424,7 +423,6 @@ sendfile:		no
 sendpage:               no
 get_unmapped_area:      no
 check_flags:            no
-dir_notify:             no
 
 ->llseek() locking has moved from llseek to the individual llseek
 implementations.  If your fs is not using generic_file_llseek, you
diff --git a/Documentation/filesystems/devpts.txt b/Documentation/filesystems/devpts.txt
new file mode 100644
index 000000000000..68dffd87f9b7
--- /dev/null
+++ b/Documentation/filesystems/devpts.txt
@@ -0,0 +1,132 @@
+
+To support containers, we now allow multiple instances of devpts filesystem,
+such that indices of ptys allocated in one instance are independent of indices
+allocated in other instances of devpts.
+
+To preserve backward compatibility, this support for multiple instances is
+enabled only if:
+
+        - CONFIG_DEVPTS_MULTIPLE_INSTANCES=y, and
+        - '-o newinstance' mount option is specified while mounting devpts
+
+IOW, devpts now supports both single-instance and multi-instance semantics.
+
+If CONFIG_DEVPTS_MULTIPLE_INSTANCES=n, there is no change in behavior and
+this referred to as the "legacy" mode. In this mode, the new mount options
+(-o newinstance and -o ptmxmode) will be ignored with a 'bogus option' message
+on console.
+
+If CONFIG_DEVPTS_MULTIPLE_INSTANCES=y and devpts is mounted without the
+'newinstance' option (as in current start-up scripts) the new mount binds
+to the initial kernel mount of devpts. This mode is referred to as the
+'single-instance' mode and the current, single-instance semantics are
+preserved, i.e PTYs are common across the system.
+
+The only difference between this single-instance mode and the legacy mode
+is the presence of new, '/dev/pts/ptmx' node with permissions 0000, which
+can safely be ignored.
+
+If CONFIG_DEVPTS_MULTIPLE_INSTANCES=y and 'newinstance' option is specified,
+the mount is considered to be in the multi-instance mode and a new instance
+of the devpts fs is created. Any ptys created in this instance are independent
+of ptys in other instances of devpts. Like in the single-instance mode, the
+/dev/pts/ptmx node is present. To effectively use the multi-instance mode,
+open of /dev/ptmx must be a redirected to '/dev/pts/ptmx' using a symlink or
+bind-mount.
+
+Eg: A container startup script could do the following:
+
+        $ chmod 0666 /dev/pts/ptmx
+        $ rm /dev/ptmx
+        $ ln -s pts/ptmx /dev/ptmx
+        $ ns_exec -cm /bin/bash
+
+        # We are now in new container
+
+        $ umount /dev/pts
+        $ mount -t devpts -o newinstance lxcpts /dev/pts
+        $ sshd -p 1234
+
+where 'ns_exec -cm /bin/bash' calls clone() with CLONE_NEWNS flag and execs
+/bin/bash in the child process.  A pty created by the sshd is not visible in
+the original mount of /dev/pts.
+
+User-space changes
+------------------
+
+In multi-instance mode (i.e '-o newinstance' mount option is specified at least
+once), following user-space issues should be noted.
+
+1. If -o newinstance mount option is never used, /dev/pts/ptmx can be ignored
+   and no change is needed to system-startup scripts.
+
+2. To effectively use multi-instance mode (i.e -o newinstance is specified)
+   administrators or startup scripts should "redirect" open of /dev/ptmx to
+   /dev/pts/ptmx using either a bind mount or symlink.
+
+        $ mount -t devpts -o newinstance devpts /dev/pts
+
+   followed by either
+
+        $ rm /dev/ptmx
+        $ ln -s pts/ptmx /dev/ptmx
+        $ chmod 666 /dev/pts/ptmx
+   or
+        $ mount -o bind /dev/pts/ptmx /dev/ptmx
+
+3. The '/dev/ptmx -> pts/ptmx' symlink is the preferred method since it
+   enables better error-reporting and treats both single-instance and
+   multi-instance mounts similarly.
+
+   But this method requires that system-startup scripts set the mode of
+   /dev/pts/ptmx correctly (default mode is 0000). The scripts can set the
+   mode by, either
+
+        - adding ptmxmode mount option to devpts entry in /etc/fstab, or
+        - using 'chmod 0666 /dev/pts/ptmx'
+
+4. If multi-instance mode mount is needed for containers, but the system
+   startup scripts have not yet been updated, container-startup scripts
+   should bind mount /dev/ptmx to /dev/pts/ptmx to avoid breaking single-
+   instance mounts.
+
+   Or, in general, container-startup scripts should use:
+
+        mount -t devpts -o newinstance -o ptmxmode=0666 devpts /dev/pts
+        if [ ! -L /dev/ptmx ]; then
+                mount -o bind /dev/pts/ptmx /dev/ptmx
+        fi
+
+   When all devpts mounts are multi-instance, /dev/ptmx can permanently be
+   a symlink to pts/ptmx and the bind mount can be ignored.
+
+5. A multi-instance mount that is not accompanied by the /dev/ptmx to
+   /dev/pts/ptmx redirection would result in an unusable/unreachable pty.
+
+        mount -t devpts -o newinstance lxcpts /dev/pts
+
+   immediately followed by:
+
+        open("/dev/ptmx")
+
+    would create a pty, say /dev/pts/7, in the initial kernel mount.
+    But /dev/pts/7 would be invisible in the new mount.
+
+6. The permissions for /dev/pts/ptmx node should be specified when mounting
+   /dev/pts, using the '-o ptmxmode=%o' mount option (default is 0000).
+
+        mount -t devpts -o newinstance -o ptmxmode=0644 devpts /dev/pts
+
+   The permissions can be later be changed as usual with 'chmod'.
+
+        chmod 666 /dev/pts/ptmx
+
+7. A mount of devpts without the 'newinstance' option results in binding to
+   initial kernel mount.  This behavior while preserving legacy semantics,
+   does not provide strict isolation in a container environment. i.e by
+   mounting devpts without the 'newinstance' option, a container could
+   get visibility into the 'host' or root container's devpts.
+   
+   To workaround this and have strict isolation, all mounts of devpts,
+   including the mount in the root container, should use the newinstance
+   option.
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 174eaff7ded9..cec829bc7291 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -58,13 +58,22 @@ Note: More extensive information for getting started with ext4 can be
 
         # mount -t ext4 /dev/hda1 /wherever
 
-  - When comparing performance with other filesystems, remember that
-    ext3/4 by default offers higher data integrity guarantees than most.
-    So when comparing with a metadata-only journalling filesystem, such
-    as ext3, use `mount -o data=writeback'.  And you might as well use
-    `mount -o nobh' too along with it.  Making the journal larger than
-    the mke2fs default often helps performance with metadata-intensive
-    workloads.
+  - When comparing performance with other filesystems, it's always
+    important to try multiple workloads; very often a subtle change in a
+    workload parameter can completely change the ranking of which
+    filesystems do well compared to others.  When comparing versus ext3,
+    note that ext4 enables write barriers by default, while ext3 does
+    not enable write barriers by default.  So it is useful to use
+    explicitly specify whether barriers are enabled or not when via the
+    '-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems
+    for a fair comparison.  When tuning ext3 for best benchmark numbers,
+    it is often worthwhile to try changing the data journaling mode; '-o
+    data=writeback,nobh' can be faster for some workloads.  (Note
+    however that running mounted with data=writeback can potentially
+    leave stale data exposed in recently written files in case of an
+    unclean shutdown, which could be a security exposure in some
+    situations.)  Configuring the filesystem with a large journal can
+    also be helpful for metadata-intensive workloads.
 
 2. Features
 ===========
@@ -74,7 +83,7 @@ Note: More extensive information for getting started with ext4 can be
 * ability to use filesystems > 16TB (e2fsprogs support not available yet)
 * extent format reduces metadata overhead (RAM, IO for access, transactions)
 * extent format more robust in face of on-disk corruption due to magics,
-* internal redunancy in tree
+* internal redundancy in tree
 * improved file allocation (multi-block alloc)
 * fix 32000 subdirectory limit
 * nsec timestamps for mtime, atime, ctime, create time
@@ -116,10 +125,11 @@ grouping of bitmaps and inode tables.  Some test results available here:
 When mounting an ext4 filesystem, the following option are accepted:
 (*) == default
 
-extents         (*)     ext4 will use extents to address file data.  The
-                        file system will no longer be mountable by ext3.
-
-noextents               ext4 will not use extents for newly created files
+ro                      Mount filesystem read only. Note that ext4 will
+                        replay the journal (and thus write to the
+                        partition) even when mounted "read only". The
+                        mount options "ro,noload" can be used to prevent
+                        writes to the filesystem.
 
 journal_checksum        Enable checksumming of the journal transactions.
                         This will allow the recovery code in e2fsck and the
@@ -134,17 +144,17 @@ journal_async_commit	Commit block can be written to disk without waiting
 journal=update          Update the ext4 file system's journal to the current
                         format.
 
-journal=inum            When a journal already exists, this option is ignored.
-                        Otherwise, it specifies the number of the inode which
-                        will represent the ext4 file system's journal file.
-
 journal_dev=devnum      When the external journal device's major/minor numbers
                         have changed, this option allows the user to specify
                         the new journal location.  The journal device is
                         identified through its new major/minor numbers encoded
                         in devnum.
 
-noload                  Don't load the journal on mounting.
+noload                  Don't load the journal on mounting.  Note that
+                        if the filesystem was not unmounted cleanly,
+                        skipping the journal replay will lead to the
+                        filesystem containing inconsistencies that can
+                        lead to any number of problems.
 
 data=journal            All data are committed into the journal prior to being
                         written into the main file system.
@@ -219,9 +229,12 @@ minixdf			Make 'df' act like Minix.
 
 debug                   Extra debugging information is sent to syslog.
 
-errors=remount-ro(*)    Remount the filesystem read-only on an error.
+errors=remount-ro       Remount the filesystem read-only on an error.
 errors=continue         Keep going on a filesystem error.
 errors=panic            Panic and halt the machine if an error occurs.
+                        (These mount options override the errors behavior
+                        specified in the superblock, which can be configured
+                        using tune2fs)
 
 data_err=ignore(*)      Just print an error message if an error occurs
                         in a file data buffer in ordered mode.
@@ -261,6 +274,42 @@ delalloc	(*)	Deferring block allocation until write-out time.
 nodelalloc              Disable delayed allocation. Blocks are allocation
                         when data is copied from user to page cache.
 
+max_batch_time=usec     Maximum amount of time ext4 should wait for
+                        additional filesystem operations to be batch
+                        together with a synchronous write operation.
+                        Since a synchronous write operation is going to
+                        force a commit and then a wait for the I/O
+                        complete, it doesn't cost much, and can be a
+                        huge throughput win, we wait for a small amount
+                        of time to see if any other transactions can
+                        piggyback on the synchronous write.   The
+                        algorithm used is designed to automatically tune
+                        for the speed of the disk, by measuring the
+                        amount of time (on average) that it takes to
+                        finish committing a transaction.  Call this time
+                        the "commit time".  If the time that the
+                        transactoin has been running is less than the
+                        commit time, ext4 will try sleeping for the
+                        commit time to see if other operations will join
+                        the transaction.   The commit time is capped by
+                        the max_batch_time, which defaults to 15000us
+                        (15ms).   This optimization can be turned off
+                        entirely by setting max_batch_time to 0.
+
+min_batch_time=usec     This parameter sets the commit time (as
+                        described above) to be at least min_batch_time.
+                        It defaults to zero microseconds.  Increasing
+                        this parameter may improve the throughput of
+                        multi-threaded, synchronous workloads on very
+                        fast disks, at the cost of increasing latency.
+
+journal_ioprio=prio     The I/O priority (from 0 to 7, where 0 is the
+                        highest priorty) which should be used for I/O
+                        operations submitted by kjournald2 during a
+                        commit operation.  This defaults to 3, which is
+                        a slightly higher priority than the default I/O
+                        priority.
+
 Data Mode
 =========
 There are 3 different data modes:
diff --git a/Documentation/filesystems/files.txt b/Documentation/filesystems/files.txt
index bb0142f61084..ac2facc50d2a 100644
--- a/Documentation/filesystems/files.txt
+++ b/Documentation/filesystems/files.txt
@@ -76,13 +76,13 @@ the fdtable structure -
 5. Handling of the file structures is special. Since the look-up
    of the fd (fget()/fget_light()) are lock-free, it is possible
    that look-up may race with the last put() operation on the
-   file structure. This is avoided using atomic_inc_not_zero()
+   file structure. This is avoided using atomic_long_inc_not_zero()
    on ->f_count :
 
         rcu_read_lock();
         file = fcheck_files(files, fd);
         if (file) {
-                if (atomic_inc_not_zero(&file->f_count))
+                if (atomic_long_inc_not_zero(&file->f_count))
                         *fput_needed = 1;
                 else
                 /* Didn't get the reference, someone's freed */
@@ -92,7 +92,7 @@ the fdtable structure -
         ....
         return file;
 
-   atomic_inc_not_zero() detects if refcounts is already zero or
+   atomic_long_inc_not_zero() detects if refcounts is already zero or
    goes to zero during increment. If it does, we fail
    fget()/fget_light().
 
diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
index 67310fbbb7df..c2a0871280a0 100644
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -31,7 +31,6 @@ Features which OCFS2 does not support yet:
         - quotas
         - Directory change notification (F_NOTIFY)
         - Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
-        - POSIX ACLs
 
 Mount options
 =============
@@ -79,3 +78,5 @@ inode64			Indicates that Ocfs2 is allowed to create inodes at
                         bits of significance.
 user_xattr      (*)     Enables Extended User Attributes.
 nouser_xattr            Disables Extended User Attributes.
+acl                     Enables POSIX Access Control Lists support.
+noacl           (*)     Disables POSIX Access Control Lists support.
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index bb1b0dd3bfcb..d105eb45282a 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -140,6 +140,7 @@ Table 1-1: Process specific entries in /proc
  statm          Process memory status information
  status         Process status in human readable form
  wchan          If CONFIG_KALLSYMS is set, a pre-decoded wchan
+ stack          Report full stack trace, enable via CONFIG_STACKTRACE
  smaps          Extension based on maps, the rss size for each mapped file
 ..............................................................................
 
@@ -1339,10 +1340,13 @@ nmi_watchdog
 
 Enables/Disables the NMI watchdog on x86 systems.  When the value is non-zero
 the NMI watchdog is enabled and will continuously test all online cpus to
-determine whether or not they are still functioning properly.
+determine whether or not they are still functioning properly. Currently,
+passing "nmi_watchdog=" parameter at boot time is required for this function
+to work.
 
-Because the NMI watchdog shares registers with oprofile, by disabling the NMI
-watchdog, oprofile may have more registers to utilize.
+If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the
+NMI watchdog shares registers with oprofile. By disabling the NMI watchdog,
+oprofile may have more registers to utilize.
 
 msgmni
 ------
@@ -1382,6 +1386,15 @@ swapcache reclaim.  Decreasing vfs_cache_pressure causes the kernel to prefer
 to retain dentry and inode caches.  Increasing vfs_cache_pressure beyond 100
 causes the kernel to prefer to reclaim dentries and inodes.
 
+dirty_background_bytes
+----------------------
+
+Contains the amount of dirty memory at which the pdflush background writeback
+daemon will start writeback.
+
+If dirty_background_bytes is written, dirty_background_ratio becomes a function
+of its value (dirty_background_bytes / the amount of dirtyable system memory).
+
 dirty_background_ratio
 ----------------------
 
@@ -1390,14 +1403,29 @@ pages + file cache, not including locked pages and HugePages), the number of
 pages at which the pdflush background writeback daemon will start writing out
 dirty data.
 
+If dirty_background_ratio is written, dirty_background_bytes becomes a function
+of its value (dirty_background_ratio * the amount of dirtyable system memory).
+
+dirty_bytes
+-----------
+
+Contains the amount of dirty memory at which a process generating disk writes
+will itself start writeback.
+
+If dirty_bytes is written, dirty_ratio becomes a function of its value
+(dirty_bytes / the amount of dirtyable system memory).
+
 dirty_ratio
------------------
+-----------
 
 Contains, as a percentage of the dirtyable system memory (free pages + mapped
 pages + file cache, not including locked pages and HugePages), the number of
 pages at which a process which is generating disk writes will itself start
 writing out dirty data.
 
+If dirty_ratio is written, dirty_bytes becomes a function of its value
+(dirty_ratio * the amount of dirtyable system memory).
+
 dirty_writeback_centisecs
 -------------------------
 
diff --git a/Documentation/filesystems/ubifs.txt b/Documentation/filesystems/ubifs.txt
index dd84ea3c10da..84da2a4ba25a 100644
--- a/Documentation/filesystems/ubifs.txt
+++ b/Documentation/filesystems/ubifs.txt
@@ -95,6 +95,9 @@ no_chk_data_crc		skip checking of CRCs on data nodes in order to
                         of this option is that corruption of the contents
                         of a file can go unnoticed.
 chk_data_crc (*)        do not skip checking CRCs on data nodes
+compr=none              override default compressor and set it to "none"
+compr=lzo               override default compressor and set it to "lzo"
+compr=zlib              override default compressor and set it to "zlib"
 
 
 Quick usage instructions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 5579bda58a6d..ef19afa186a9 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -733,7 +733,6 @@ struct file_operations {
         ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
         unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
         int (*check_flags)(int);
-        int (*dir_notify)(struct file *filp, unsigned long arg);
         int (*flock) (struct file *, int, struct file_lock *);
         ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned int);
         ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
@@ -800,8 +799,6 @@ otherwise noted.
 
   check_flags: called by the fcntl(2) system call for F_SETFL command
 
-  dir_notify: called by the fcntl(2) system call for F_NOTIFY command
-
   flock: called by the flock(2) system call
 
   splice_write: called by the VFS to splice data from a pipe to a file. This
@@ -931,7 +928,7 @@ manipulate dentries:
   d_lookup: look up a dentry given its parent and path name component
         It looks up the child of that given name from the dcache
         hash table. If it is found, the reference count is incremented
-        and the dentry is returned. The caller must use d_put()
+        and the dentry is returned. The caller must use dput()
         to free the dentry when it finishes using it.
 
 For further information on dentry locking, please refer to the document
diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt
index 0a1668ba2600..9878f50d6ed6 100644
--- a/Documentation/filesystems/xfs.txt
+++ b/Documentation/filesystems/xfs.txt
@@ -229,10 +229,6 @@ The following sysctls are available for the XFS filesystem:
         ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
         is set.
 
-  fs.xfs.restrict_chown         (Min: 0  Default: 1  Max: 1)
-        Controls whether unprivileged users can use chown to "give away"
-        a file to another user.
-
   fs.xfs.inherit_sync           (Min: 0  Default: 1  Max: 1)
         Setting this to "1" will cause the "sync" flag set
         by the xfs_io(8) chattr command on a directory to be