Hi Jan,
Thank you for the review.
On 04/19, Jan Kara wrote:
> On Thu 29-03-18 18:44:29, Jaegeuk Kim wrote:
> > 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(-)
>
> Thanks for the patch. Some comments below.
>
> >
> > 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, "
>
> So return value of ext4_setup_super() looks a bit strange and it seems it
> currently returns 0 or SB_RDONLY. So I think you first need to clean this
Indeed. I'll update it in v2.
> up before making ext4_setup_super() return error code (as your patch could
> make ext4_fill_super() return SB_RDONLY under some circumstances).
Interestingly, it only affects ext4_remount() only. :P
>
> > @@ -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);
>
> I'd rather rewrite this as:
> if (buffer_write_io_error(sbh)) {
> do stuff as now
> }
> if (error)
> return error;
Got it.
Thanks,
>
> Honza
> --
> Jan Kara <jack@xxxxxxxx>
> SUSE Labs, CR
