10 files changed, 88 insertions, 9 deletions

diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index 4dc28cc93503..571785887a4f 100644
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -4,6 +4,8 @@ Exporting
         - explanation of how to make filesystems exportable.
 Locking
         - info on locking rules as they pertain to Linux VFS.
+9p.txt
+        - 9p (v9fs) is an implementation of the Plan 9 remote fs protocol.
 adfs.txt
         - info and mount options for the Acorn Advanced Disc Filing System.
 afs.txt
@@ -82,8 +84,6 @@ udf.txt
         - info and mount options for the UDF filesystem.
 ufs.txt
         - info on the ufs filesystem.
-v9fs.txt
-        - v9fs is a Unix implementation of the Plan 9 9p remote fs protocol.
 vfat.txt
         - info on using the VFAT filesystem used in Windows NT and Windows 95
 vfs.txt
diff --git a/Documentation/filesystems/9p.txt b/Documentation/filesystems/9p.txt
index 4d075a4558f9..bbd8b28c13de 100644
--- a/Documentation/filesystems/9p.txt
+++ b/Documentation/filesystems/9p.txt
@@ -40,6 +40,10 @@ OPTIONS
   aname=name    aname specifies the file tree to access when the server is
                 offering several exported file systems.
 
+  cache=mode    specifies a cacheing policy.  By default, no caches are used.
+                        loose = no attempts are made at consistency,
+                                intended for exclusive, read-only mounts
+
   debug=n       specifies debug level.  The debug level is a bitmask.
                         0x01 = display verbose error messages
                         0x02 = developer debug (DEBUG_CURRENT)
diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index a9b6301a04fc..90419715c7e9 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -136,7 +136,8 @@ struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
 }
 
 /**
- * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and release it
+ * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and
+ *                      release it
  * @dentry: dentry to look for fid in
  *
  * find a fid in the dentry and then clone to a new private fid
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index d9b561ba5e58..6ad6f192b6e4 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -53,6 +53,8 @@ enum {
         Opt_uname, Opt_remotename,
         /* Options that take no arguments */
         Opt_legacy, Opt_nodevmap, Opt_unix, Opt_tcp, Opt_fd,
+        /* Cache options */
+        Opt_cache_loose,
         /* Error token */
         Opt_err
 };
@@ -76,6 +78,8 @@ static match_table_t tokens = {
         {Opt_fd, "fd"},
         {Opt_legacy, "noextend"},
         {Opt_nodevmap, "nodevmap"},
+        {Opt_cache_loose, "cache=loose"},
+        {Opt_cache_loose, "loose"},
         {Opt_err, NULL}
 };
 
@@ -106,6 +110,7 @@ static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
         v9ses->debug = 0;
         v9ses->rfdno = ~0;
         v9ses->wfdno = ~0;
+        v9ses->cache = 0;
 
         if (!options)
                 return;
@@ -121,7 +126,6 @@ static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
                                         "integer field, but no integer?\n");
                                 continue;
                         }
-
                 }
                 switch (token) {
                 case Opt_port:
@@ -169,6 +173,9 @@ static void v9fs_parse_options(char *options, struct v9fs_session_info *v9ses)
                 case Opt_nodevmap:
                         v9ses->nodev = 1;
                         break;
+                case Opt_cache_loose:
+                        v9ses->cache = CACHE_LOOSE;
+                        break;
                 default:
                         continue;
                 }
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index c134d104cb28..820bf5ca35d8 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -47,7 +47,7 @@ struct v9fs_session_info {
         unsigned int afid;      /* authentication fid */
         unsigned int rfdno;     /* read file descriptor number */
         unsigned int wfdno;     /* write file descriptor number */
-
+        unsigned int cache;     /* cache mode */
 
         char *name;             /* user name to mount as */
         char *remotename;       /* name of remote hierarchy being mounted */
@@ -73,6 +73,13 @@ enum {
         PROTO_FD,
 };
 
+/* possible values of ->cache */
+/* eventually support loose, tight, time, session, default always none */
+enum {
+        CACHE_NONE,             /* default */
+        CACHE_LOOSE,            /* no consistency */
+};
+
 extern struct dentry *v9fs_debugfs_root;
 
 int v9fs_session_init(struct v9fs_session_info *, const char *, char *);
diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index 450b0c1b385e..8ada4c5c5d70 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -40,8 +40,10 @@
 extern struct file_system_type v9fs_fs_type;
 extern const struct address_space_operations v9fs_addr_operations;
 extern const struct file_operations v9fs_file_operations;
+extern const struct file_operations v9fs_cached_file_operations;
 extern const struct file_operations v9fs_dir_operations;
 extern struct dentry_operations v9fs_dentry_operations;
+extern struct dentry_operations v9fs_cached_dentry_operations;
 
 struct inode *v9fs_get_inode(struct super_block *sb, int mode);
 ino_t v9fs_qid2ino(struct v9fs_qid *qid);
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index cc24abf232d5..bed48fa96521 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -63,6 +63,8 @@ static int v9fs_vfs_readpage(struct file *filp, struct page *page)
         int total = 0;
         int result = 0;
 
+        dprintk(DEBUG_VFS, "\n");
+
         buffer = kmap(page);
         do {
                 if (count < rsize)
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index 062daa6000ab..ddffd8aa902d 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -53,10 +53,31 @@
 static int v9fs_dentry_delete(struct dentry *dentry)
 {
         dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
+
         return 1;
 }
 
 /**
+ * v9fs_cached_dentry_delete - called when dentry refcount equals 0
+ * @dentry:  dentry in question
+ *
+ * Only return 1 if our inode is invalid.  Only non-synthetic files
+ * (ones without mtime == 0) should be calling this function.
+ *
+ */
+
+static int v9fs_cached_dentry_delete(struct dentry *dentry)
+{
+        struct inode *inode = dentry->d_inode;
+        dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
+
+        if(!inode)
+                return 1;
+
+        return 0;
+}
+
+/**
  * v9fs_dentry_release - called when dentry is going to be freed
  * @dentry:  dentry that is being release
  *
@@ -87,6 +108,11 @@ void v9fs_dentry_release(struct dentry *dentry)
         }
 }
 
+struct dentry_operations v9fs_cached_dentry_operations = {
+        .d_delete = v9fs_cached_dentry_delete,
+        .d_release = v9fs_dentry_release,
+};
+
 struct dentry_operations v9fs_dentry_operations = {
         .d_delete = v9fs_dentry_delete,
         .d_release = v9fs_dentry_release,
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 6c78343cf690..653dfa5b2531 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -79,6 +79,13 @@ int v9fs_file_open(struct inode *inode, struct file *file)
         vfid->filp = file;
         kfree(fcall);
 
+        if((vfid->qid.version) && (v9ses->cache)) {
+                dprintk(DEBUG_VFS, "cached");
+                /* enable cached file options */
+                if(file->f_op == &v9fs_file_operations)
+                        file->f_op = &v9fs_cached_file_operations;
+        }
+
         return 0;
 
 Clunk_Fid:
@@ -238,6 +245,17 @@ v9fs_file_write(struct file *filp, const char __user * data,
         return total;
 }
 
+const struct file_operations v9fs_cached_file_operations = {
+        .llseek = generic_file_llseek,
+        .read = do_sync_read,
+        .aio_read = generic_file_aio_read,
+        .write = v9fs_file_write,
+        .open = v9fs_file_open,
+        .release = v9fs_dir_release,
+        .lock = v9fs_file_lock,
+        .mmap = generic_file_mmap,
+};
+
 const struct file_operations v9fs_file_operations = {
         .llseek = generic_file_llseek,
         .read = v9fs_file_read,
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 5cf22134826b..124a085d1f2e 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -504,7 +504,10 @@ v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
                 goto error;
         }
 
-        dentry->d_op = &v9fs_dentry_operations;
+        if(v9ses->cache)
+                dentry->d_op = &v9fs_cached_dentry_operations;
+        else
+                dentry->d_op = &v9fs_dentry_operations;
         d_instantiate(dentry, inode);
 
         if (nd && nd->flags & LOOKUP_OPEN) {
@@ -589,7 +592,10 @@ static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
                 goto error;
         }
 
-        dentry->d_op = &v9fs_dentry_operations;
+        if(v9ses->cache)
+                dentry->d_op = &v9fs_cached_dentry_operations;
+        else
+                dentry->d_op = &v9fs_dentry_operations;
         d_instantiate(dentry, inode);
         return 0;
 
@@ -626,7 +632,6 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 
         sb = dir->i_sb;
         v9ses = v9fs_inode2v9ses(dir);
-        dentry->d_op = &v9fs_dentry_operations;
         dirfid = v9fs_fid_lookup(dentry->d_parent);
 
         if(IS_ERR(dirfid))
@@ -697,6 +702,10 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 
         fid->qid = fcall->params.rstat.stat.qid;
         v9fs_stat2inode(&fcall->params.rstat.stat, inode, inode->i_sb);
+        if((fid->qid.version)&&(v9ses->cache))
+                dentry->d_op = &v9fs_cached_dentry_operations;
+        else
+                dentry->d_op = &v9fs_dentry_operations;
 
         d_add(dentry, inode);
         kfree(fcall);
@@ -1184,7 +1193,10 @@ static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
                 goto free_vfid;
         }
 
-        dentry->d_op = &v9fs_dentry_operations;
+        if(v9ses->cache)
+                dentry->d_op = &v9fs_cached_dentry_operations;
+        else
+                dentry->d_op = &v9fs_dentry_operations;
         d_instantiate(dentry, inode);
         return 0;