fuse: trust kernel i_ctime only

Let the kernel maintain i_ctime locally: update i_ctime explicitly on
truncate, fallocate, open(O_TRUNC), setxattr, removexattr, link, rename,
unlink.

The inode flag I_DIRTY_SYNC serves as indication that local i_ctime should
be flushed to the server eventually.  The patch sets the flag and updates
i_ctime in course of operations listed above.

Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

2 files changed, 24 insertions, 4 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 65357bd1d17b..f62ab8eedb5f 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -679,6 +679,14 @@ static int fuse_symlink(struct inode *dir, struct dentry *entry,
         return create_new_entry(fc, req, dir, entry, S_IFLNK);
 }
 
+static inline void fuse_update_ctime(struct inode *inode)
+{
+        if (!IS_NOCMTIME(inode)) {
+                inode->i_ctime = current_fs_time(inode->i_sb);
+                mark_inode_dirty_sync(inode);
+        }
+}
+
 static int fuse_unlink(struct inode *dir, struct dentry *entry)
 {
         int err;
@@ -713,6 +721,7 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
                 fuse_invalidate_attr(inode);
                 fuse_invalidate_attr(dir);
                 fuse_invalidate_entry_cache(entry);
+                fuse_update_ctime(inode);
         } else if (err == -EINTR)
                 fuse_invalidate_entry(entry);
         return err;
@@ -771,6 +780,7 @@ static int fuse_rename(struct inode *olddir, struct dentry *oldent,
         if (!err) {
                 /* ctime changes */
                 fuse_invalidate_attr(oldent->d_inode);
+                fuse_update_ctime(oldent->d_inode);
 
                 fuse_invalidate_attr(olddir);
                 if (olddir != newdir)
@@ -780,6 +790,7 @@ static int fuse_rename(struct inode *olddir, struct dentry *oldent,
                 if (newent->d_inode) {
                         fuse_invalidate_attr(newent->d_inode);
                         fuse_invalidate_entry_cache(newent);
+                        fuse_update_ctime(newent->d_inode);
                 }
         } else if (err == -EINTR) {
                 /* If request was interrupted, DEITY only knows if the
@@ -829,6 +840,7 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
                 inc_nlink(inode);
                 spin_unlock(&fc->lock);
                 fuse_invalidate_attr(inode);
+                fuse_update_ctime(inode);
         } else if (err == -EINTR) {
                 fuse_invalidate_attr(inode);
         }
@@ -846,6 +858,8 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
                 attr->size = i_size_read(inode);
                 attr->mtime = inode->i_mtime.tv_sec;
                 attr->mtimensec = inode->i_mtime.tv_nsec;
+                attr->ctime = inode->i_ctime.tv_sec;
+                attr->ctimensec = inode->i_ctime.tv_nsec;
         }
 
         stat->dev = inode->i_sb->s_dev;
@@ -1811,8 +1825,10 @@ static int fuse_setxattr(struct dentry *entry, const char *name,
                 fc->no_setxattr = 1;
                 err = -EOPNOTSUPP;
         }
-        if (!err)
+        if (!err) {
                 fuse_invalidate_attr(inode);
+                fuse_update_ctime(inode);
+        }
         return err;
 }
 
@@ -1942,8 +1958,10 @@ static int fuse_removexattr(struct dentry *entry, const char *name)
                 fc->no_removexattr = 1;
                 err = -EOPNOTSUPP;
         }
-        if (!err)
+        if (!err) {
                 fuse_invalidate_attr(inode);
+                fuse_update_ctime(inode);
+        }
         return err;
 }
 
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 560eafcdd6a7..e9ecb1878109 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -175,9 +175,9 @@ void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
                 inode->i_mtime.tv_sec   = attr->mtime;
                 inode->i_mtime.tv_nsec  = attr->mtimensec;
+                inode->i_ctime.tv_sec   = attr->ctime;
+                inode->i_ctime.tv_nsec  = attr->ctimensec;
         }
-        inode->i_ctime.tv_sec   = attr->ctime;
-        inode->i_ctime.tv_nsec  = attr->ctimensec;
 
         if (attr->blksize != 0)
                 inode->i_blkbits = ilog2(attr->blksize);
@@ -256,6 +256,8 @@ static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
         inode->i_size = attr->size;
         inode->i_mtime.tv_sec  = attr->mtime;
         inode->i_mtime.tv_nsec = attr->mtimensec;
+        inode->i_ctime.tv_sec  = attr->ctime;
+        inode->i_ctime.tv_nsec = attr->ctimensec;
         if (S_ISREG(inode->i_mode)) {
                 fuse_init_common(inode);
                 fuse_init_file_inode(inode);