From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> When remounting ext4 from ro to rw, currently it allows its transition, even if ext4_commit_super() returns EIO. Even worse thing is, after that, fs/buffer complains buffer dirty bits like: Call trace: [<ffffff9750c259dc>] mark_buffer_dirty+0x184/0x1a4 [<ffffff9750cb398c>] __ext4_handle_dirty_super+0x4c/0xfc [<ffffff9750c7a9fc>] ext4_file_open+0x154/0x1c0 [<ffffff9750bea51c>] do_dentry_open+0x114/0x2d0 [<ffffff9750bea75c>] vfs_open+0x5c/0x94 [<ffffff9750bf879c>] path_openat+0x668/0xfe8 [<ffffff9750bf8088>] do_filp_open+0x74/0x120 [<ffffff9750beac98>] do_sys_open+0x148/0x254 [<ffffff9750beade0>] SyS_openat+0x10/0x18 [<ffffff9750a83ab0>] el0_svc_naked+0x24/0x28 EXT4-fs (dm-1): previous I/O error to superblock detected Buffer I/O error on dev dm-1, logical block 0, lost sync page write EXT4-fs (dm-1): re-mounted. Opts: (null) Buffer I/O error on dev dm-1, logical block 80, lost async page write Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx> Cc: linux-ext4@xxxxxxxxxxxxxxx Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> --- fs/ext4/super.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 39bf464c35f1..b268bfea879c 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2151,7 +2151,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es, if (sbi->s_journal) ext4_set_feature_journal_needs_recovery(sb); - ext4_commit_super(sb, 1); + res = ext4_commit_super(sb, 1); done: if (test_opt(sb, DEBUG)) printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, " @@ -4739,11 +4739,10 @@ static int ext4_commit_super(struct super_block *sb, int sync) unlock_buffer(sbh); error = __sync_dirty_buffer(sbh, REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0)); - if (error) + if (error && !buffer_write_io_error(sbh)) return error; - error = buffer_write_io_error(sbh); - if (error) { + if (buffer_write_io_error(sbh)) { ext4_msg(sb, KERN_ERR, "I/O error while writing " "superblock"); clear_buffer_write_io_error(sbh); @@ -5144,8 +5143,12 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) if (sbi->s_journal) ext4_clear_journal_err(sb, es); sbi->s_mount_state = le16_to_cpu(es->s_state); - if (!ext4_setup_super(sb, es, 0)) - sb->s_flags &= ~SB_RDONLY; + + err = ext4_setup_super(sb, es, 0); + if (err) + goto restore_opts; + + sb->s_flags &= ~SB_RDONLY; if (ext4_has_feature_mmp(sb)) if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block))) { @@ -5169,8 +5172,10 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) } ext4_setup_system_zone(sb); - if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) - ext4_commit_super(sb, 1); + if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) { + err = ext4_commit_super(sb, 1); + goto restore_opts; + } #ifdef CONFIG_QUOTA /* Release old quota file names */ -- 2.15.0.531.g2ccb3012c9-goog