The patch titled
Subject: nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Subject: nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors
Date: Tue, 4 Jun 2024 22:42:55 +0900
The error handling in nilfs_empty_dir() when a directory folio/page read
fails is incorrect, as in the old ext2 implementation, and if the
folio/page cannot be read or nilfs_check_folio() fails, it will falsely
determine the directory as empty and corrupt the file system.
In addition, since nilfs_empty_dir() does not immediately return on a
failed folio/page read, but continues to loop, this can cause a long loop
with I/O if i_size of the directory's inode is also corrupted, causing the
log writer thread to wait and hang, as reported by syzbot.
Fix these issues by making nilfs_empty_dir() immediately return a false
value (0) if it fails to get a directory folio/page.
Link: https://lkml.kernel.org/r/20240604134255.7165-1-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Reported-by: syzbot+c8166c541d3971bf6c87@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/dir.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/nilfs2/dir.c~nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors
+++ a/fs/nilfs2/dir.c
@@ -607,7 +607,7 @@ int nilfs_empty_dir(struct inode *inode)
kaddr = nilfs_get_folio(inode, i, &folio);
if (IS_ERR(kaddr))
- continue;
+ return 0;
de = (struct nilfs_dir_entry *)kaddr;
kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxx are
nilfs2-fix-potential-kernel-bug-due-to-lack-of-writeback-flag-waiting.patch
nilfs2-fix-nilfs_empty_dir-misjudgment-and-long-loop-on-i-o-errors.patch
