Inotify does not currently know when a filesystem
is acting as a wrapper around another fs. This means
that inotify watchers will miss any modifications to
the base file, as well as any made in a separate
stacked fs that points to the same file.
d_canonical_path solves this problem by allowing the fs
to map a dentry to a path in the lower fs. Inotify
can use it to find the appropriate place to watch to
be informed of all changes to a file.
Change-Id: I09563baffad1711a045e45c1bd0bd8713c2cc0b6
Signed-off-by: Daniel Rosenberg <drosen@google.com>
struct fsnotify_group *group;
struct inode *inode;
struct path path;
struct fsnotify_group *group;
struct inode *inode;
struct path path;
+ struct path alteredpath;
+ struct path *canonical_path = &path;
struct fd f;
int ret;
unsigned flags = 0;
struct fd f;
int ret;
unsigned flags = 0;
if (ret)
goto fput_and_out;
if (ret)
goto fput_and_out;
+ /* support stacked filesystems */
+ if(path.dentry && path.dentry->d_op) {
+ if (path.dentry->d_op->d_canonical_path) {
+ path.dentry->d_op->d_canonical_path(path.dentry, &alteredpath);
+ canonical_path = &alteredpath;
+ path_put(&path);
+ }
+ }
+
/* inode held in place by reference to path; group by fget on fd */
/* inode held in place by reference to path; group by fget on fd */
- inode = path.dentry->d_inode;
+ inode = canonical_path->dentry->d_inode;
group = f.file->private_data;
/* create/update an inode mark */
ret = inotify_update_watch(group, inode, mask);
group = f.file->private_data;
/* create/update an inode mark */
ret = inotify_update_watch(group, inode, mask);
+ path_put(canonical_path);
fput_and_out:
fdput(f);
return ret;
fput_and_out:
fdput(f);
return ret;
BUILD_BUG_ON(IN_ISDIR != FS_ISDIR);
BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
BUILD_BUG_ON(IN_ISDIR != FS_ISDIR);
BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
- BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21);
+ BUG_ON(hweight32(ALL_INOTIFY_BITS) != 22);
inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC);
inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC);
struct vfsmount *(*d_automount)(struct path *);
int (*d_manage)(struct dentry *, bool);
struct inode *(*d_select_inode)(struct dentry *, unsigned);
struct vfsmount *(*d_automount)(struct path *);
int (*d_manage)(struct dentry *, bool);
struct inode *(*d_select_inode)(struct dentry *, unsigned);
+ void (*d_canonical_path)(const struct dentry *, struct path *);
} ____cacheline_aligned;
/*
} ____cacheline_aligned;
/*