From 269cdf353b5bdd15f1a079671b0f889113865f20 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Wed, 13 Mar 2024 19:58:27 +0900 Subject: [PATCH] nilfs2: prevent kernel bug at submit_bh_wbc() Fix a bug where nilfs_get_block() returns a successful status when searching and inserting the specified block both fail inconsistently. If this inconsistent behavior is not due to a previously fixed bug, then an unexpected race is occurring, so return a temporary error -EAGAIN instead. This prevents callers such as __block_write_begin_int() from requesting a read into a buffer that is not mapped, which would cause the BUG_ON check for the BH_Mapped flag in submit_bh_wbc() to fail. Link: https://lkml.kernel.org/r/20240313105827.5296-3-konishi.ryusuke@gmail.com Fixes: 1f5abe7e7dbc ("nilfs2: replace BUG_ON and BUG calls triggerable from ioctl") Signed-off-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton --- fs/nilfs2/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index a475095a5e80..7340a01d80e1 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -112,7 +112,7 @@ int nilfs_get_block(struct inode *inode, sector_t blkoff, "%s (ino=%lu): a race condition while inserting a data block at offset=%llu", __func__, inode->i_ino, (unsigned long long)blkoff); - err = 0; + err = -EAGAIN; } nilfs_transaction_abort(inode->i_sb); goto out;