On Sat, Apr 12, 2025 at 03:36:00PM -0700, Linus Torvalds wrote: > Indeed. I sent a query to the ext4 list (and I think you) about > whether my test was even the right one. Sorry, I must have not seen that message; at least, I don't have any memory of it. > Also, while I did a "getfattr -dR" to see if there are any *existing* > attributes (and couldn't find any), I also assume that if a file has > ever *had* any attributes, the filesystem may have the attribute block > allocated even if it's now empty. Well, getfattr will only show user xattrs. It won't show security.* xattr's that might have been set by SELinux, or a system.posix_acl_access xattr. > I assume there's some trivial e2fstools thing to show things like > that, but it needs more ext4 specific knowledge than I have. Yes, we can test for this using the debugfs command. For exaple: root@kvm-xfstests:~# debugfs /dev/vdc debugfs 1.47.2-rc1 (28-Nov-2024) debugfs: stat <13> Inode: 13 Type: regular Mode: 0644 Flags: 0x80000 Generation: 1672288850 Version: 0x00000000:00000003 User: 0 Group: 0 Project: 0 Size: 286 File ACL: 0 Links: 1 Blockcount: 8 Fragment: Address: 0 Number: 0 Size: 0 ctime: 0x67faf5d0:30d0b2e4 -- Sat Apr 12 19:22:56 2025 atime: 0x67faf571:7064bd50 -- Sat Apr 12 19:21:21 2025 mtime: 0x67faf571:71236aa8 -- Sat Apr 12 19:21:21 2025 crtime: 0x67faf571:7064bd50 -- Sat Apr 12 19:21:21 2025 Size of extra inode fields: 32 Extended attributes: system.posix_acl_access (28) = 01 00 00 00 01 00 06 00 02 00 04 00 b7 7a 00 00 04 00 04 00 10 00 04 00 20 00 04 00 Inode checksum: 0xc8f7f1a7 EXTENTS: (0):33792 (If you know the pathname instead of the inode number, you can also give that to debugfs's stat command, e.g., "stat /lost+found") I tested it with a simple variant of your patch, and seems to do the right thing. Mateusz, if you want, try the following patch, and then mount your test file system with "mount -o debug". (The test_opt is to avoid a huge amount of noise on your root file system; you can skip it if it's more trouble than it's worth.) The patch has a reversed seense of the test, so it will print a message for every one where cache_no_acl *wouldn't* be called. You casn then use debugfs's "stat <ino#>" to verify whether it has some kind of extended attribute. - Ted diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f386de8c12f6..3e0ba7c4723a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5109,6 +5109,11 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, goto bad_inode; brelse(iloc.bh); + if (test_opt(sb, DEBUG) && + (ext4_test_inode_state(inode, EXT4_STATE_XATTR) || + ei->i_file_acl)) + ext4_msg(sb, KERN_DEBUG, "has xattr ino %lu", inode->i_ino); + unlock_new_inode(inode); return inode;
