From: Eric Sandeen <sandeen@xxxxxxxxxx> [ Upstream commit c96e2b8564adfb8ac14469ebc51ddc1bfecb3ae2 ] Under some circumstances we may encounter a filesystem error on a read-only block device, and if we try to save the error info to the superblock and commit it, we'll wind up with a noisy error and backtrace, i.e.: [ 3337.146838] EXT4-fs error (device pmem1p2): ext4_get_journal_inode:4634: comm mount: inode #0: comm mount: iget: illegal inode # ------------[ cut here ]------------ generic_make_request: Trying to write to read-only block-device pmem1p2 (partno 2) WARNING: CPU: 107 PID: 115347 at block/blk-core.c:788 generic_make_request_checks+0x6b4/0x7d0 ... To avoid this, commit the error info in the superblock only if the block device is writable. Reported-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx> Link: https://lore.kernel.org/r/4b6e774d-cc00-3469-7abb-108eb151071a@xxxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ext4/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index cc8c738480e8a..bf949fcc970ab 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -388,7 +388,8 @@ static void save_error_info(struct super_block *sb, const char *func, unsigned int line) { __save_error_info(sb, func, line); - ext4_commit_super(sb, 1); + if (!bdev_read_only(sb->s_bdev)) + ext4_commit_super(sb, 1); } /* -- 2.20.1
