Thread (34 messages) 34 messages, 8 authors, 2024-10-09

Re: lsm sb_delete hook, was Re: [PATCH 4/7] vfs: Convert sb->s_inodes iteration to super_iter_inodes()

From: Jan Kara <jack@suse.cz>
Date: 2024-10-03 11:57:28
Also in: linux-bcachefs, linux-fsdevel, linux-xfs

On Thu 03-10-24 00:38:05, Christoph Hellwig wrote:
On Thu, Oct 03, 2024 at 12:23:41AM -0700, Christoph Hellwig wrote:
quoted
On Wed, Oct 02, 2024 at 11:33:21AM +1000, Dave Chinner wrote:
quoted
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -1223,109 +1223,60 @@ static void hook_inode_free_security_rcu(void *inode_security)
 
 /*
  * Release the inodes used in a security policy.
- *
- * Cf. fsnotify_unmount_inodes() and invalidate_inodes()
  */
+static int release_inode_fn(struct inode *inode, void *data)
Looks like this is called from the sb_delete LSM hook, which
is only implemented by landlock, and only called from
generic_shutdown_super, separated from evict_inodes only by call
to fsnotify_sb_delete.  Why did LSM not hook into that and instead
An the main thing that fsnotify_sb_delete does is yet another inode
iteration..

Ay chance you all could get together an figure out how to get down
to a single sb inode iteration per unmount?
Fair enough. If we go with the iterator variant I've suggested to Dave in
[1], we could combine the evict_inodes(), fsnotify_unmount_inodes() and
Landlocks hook_sb_delete() into a single iteration relatively easily. But
I'd wait with that convertion until this series lands.

								Honza

[1] https://lore.kernel.org/all/20241003114555.bl34fkqsja4s5tok@quack3 (local)
-- 
Jan Kara [off-list ref]
SUSE Labs, CR
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