This is a note to let you know that I've just added the patch titled
ext4: fix race writing to an inline_data file while its xattrs are changing
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-race-writing-to-an-inline_data-file-while-its-xattrs-are-changing.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a54c4613dac1500b40e4ab55199f7c51f028e848 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Fri, 20 Aug 2021 23:44:17 -0400
Subject: ext4: fix race writing to an inline_data file while its xattrs are changing
From: Theodore Ts'o <tytso@xxxxxxx>
commit a54c4613dac1500b40e4ab55199f7c51f028e848 upstream.
The location of the system.data extended attribute can change whenever
xattr_sem is not taken. So we need to recalculate the i_inline_off
field since it mgiht have changed between ext4_write_begin() and
ext4_write_end().
This means that caching i_inline_off is probably not helpful, so in
the long run we should probably get rid of it and shrink the in-memory
ext4 inode slightly, but let's fix the race the simple way for now.
Cc: stable@xxxxxxxxxx
Fixes: f19d5870cbf72 ("ext4: add normal write support for inline data")
Reported-by: syzbot+13146364637c7363a7de@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/inline.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -750,6 +750,12 @@ int ext4_write_inline_data_end(struct in
ext4_write_lock_xattr(inode, &no_expand);
BUG_ON(!ext4_has_inline_data(inode));
+ /*
+ * ei->i_inline_off may have changed since ext4_write_begin()
+ * called ext4_try_to_write_inline_data()
+ */
+ (void) ext4_find_inline_data_nolock(inode);
+
kaddr = kmap_atomic(page);
ext4_write_inline_data(inode, &iloc, kaddr, pos, len);
kunmap_atomic(kaddr);
Patches currently in stable-queue which might be from tytso@xxxxxxx are
queue-5.14/ext4-fix-e2fsprogs-checksum-failure-for-mounted-filesystem.patch
queue-5.14/ext4-fix-race-writing-to-an-inline_data-file-while-its-xattrs-are-changing.patch
