This is a note to let you know that I've just added the patch titled
erofs: ensure m_llen is reset to 0 if metadata is invalid
to the 6.1-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:
erofs-ensure-m_llen-is-reset-to-0-if-metadata-is-inv.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit bc02d30a14b00feaaca36c7d6e6c14c4ffebaf89
Author: Gao Xiang <xiang@xxxxxxxxxx>
Date: Sun Jun 30 02:57:43 2024 +0800
erofs: ensure m_llen is reset to 0 if metadata is invalid
[ Upstream commit 9b32b063be1001e322c5f6e01f2a649636947851 ]
Sometimes, the on-disk metadata might be invalid due to user
interrupts, storage failures, or other unknown causes.
In that case, z_erofs_map_blocks_iter() may still return a valid
m_llen while other fields remain invalid (e.g., m_plen can be 0).
Due to the return value of z_erofs_scan_folio() in some path will
be ignored on purpose, the following z_erofs_scan_folio() could
then use the invalid value by accident.
Let's reset m_llen to 0 to prevent this.
Link: https://lore.kernel.org/r/20240629185743.2819229-1-hsiangkao@xxxxxxxxxxxxxxxxx
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index abcded1acd194..4864863cd1298 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -763,6 +763,8 @@ int z_erofs_map_blocks_iter(struct inode *inode, struct erofs_map_blocks *map,
err = z_erofs_do_map_blocks(inode, map, flags);
out:
+ if (err)
+ map->m_llen = 0;
trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
/* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
