A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 10:41:38 -04:00
Code Issues Projects Releases Packages Wiki Activity

fsnotify: invalidate dcache before IN_DELETE event

Browse source 
commit a37d9a17f099072fe4d3a9048b0321978707a918 upstream.

Apparently, there are some applications that use IN_DELETE event as an
invalidation mechanism and expect that if they try to open a file with
the name reported with the delete event, that it should not contain the
content of the deleted file.

Commit 49246466a9 ("fsnotify: move fsnotify_nameremove() hook out of
d_delete()") moved the fsnotify delete hook before d_delete() so fsnotify
will have access to a positive dentry.

This allowed a race where opening the deleted file via cached dentry
is now possible after receiving the IN_DELETE event.

To fix the regression, create a new hook fsnotify_delete() that takes
the unlinked inode as an argument and use a helper d_delete_notify() to
pin the inode, so we can pass it to fsnotify_delete() after d_delete().

Backporting hint: this regression is from v5.3. Although patch will
apply with only trivial conflicts to v5.4 and v5.10, it won't build,
because fsnotify_delete() implementation is different in each of those
versions (see fsnotify_link()).

A follow up patch will fix the fsnotify_unlink/rmdir() calls in pseudo
filesystem that do not need to call d_delete().

Link: https://lore.kernel.org/r/[email protected]
Reported-by: Ivan Delalande <[email protected]>
Link: https://lore.kernel.org/linux-fsdevel/YeNyzoDM5hP5LtGW@visor/
Fixes: 49246466a9 ("fsnotify: move fsnotify_nameremove() hook out of d_delete()")
Cc: [email protected] # v5.3+
Signed-off-by: Amir Goldstein <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
Amir Goldstein 2022-01-20 23:53:04 +02:00 • committed by Greg Kroah-Hartman
commit 33a9ba52d5
3 changed files with 49 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

6
fs/btrfs/ioctl.c
View file

@ -3027,10 +3027,8 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
inode_lock(inode);
err = btrfs_delete_subvolume(dir, dentry);
inode_unlock(inode);
if (!err) {
fsnotify_rmdir(dir, dentry);
d_delete(dentry);
}
if (!err)
d_delete_notify(dir, dentry);
out_dput:
dput(dentry);

10
fs/namei.c
View file

@ -3878,13 +3878,12 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
dentry->d_inode->i_flags |= S_DEAD;
dont_mount(dentry);
detach_mounts(dentry);
fsnotify_rmdir(dir, dentry);
out:
inode_unlock(dentry->d_inode);
dput(dentry);
if (!error)
d_delete(dentry);
d_delete_notify(dir, dentry);
return error;
}
EXPORT_SYMBOL(vfs_rmdir);
@ -3995,7 +3994,6 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate
if (!error) {
dont_mount(dentry);
detach_mounts(dentry);
fsnotify_unlink(dir, dentry);
}
}
}
@ -4003,9 +4001,11 @@ out:
inode_unlock(target);
/* We don't d_delete() NFS sillyrenamed files--they still exist. */
if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
if (!error && dentry->d_flags & DCACHE_NFSFS_RENAMED) {
fsnotify_unlink(dir, dentry);
} else if (!error) {
fsnotify_link_count(target);
d_delete(dentry);
d_delete_notify(dir, dentry);
}
return error;