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Date: Thu, 19 Apr 2018 17:18:53 +0200 From: Jan Kara <jack@...e.cz> To: Jaegeuk Kim <jaegeuk@...nel.org> Cc: linux-kernel@...r.kernel.org, Jaegeuk Kim <jaegeuk@...gle.com>, Theodore Ts'o <tytso@....edu>, Andreas Dilger <adilger.kernel@...ger.ca>, linux-ext4@...r.kernel.org Subject: Re: [PATCH] ext4: handle errors on ext4_commit_super On Thu 29-03-18 18:44:29, Jaegeuk Kim wrote: > From: Jaegeuk Kim <jaegeuk@...gle.com> > > 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@....edu> > Cc: Andreas Dilger <adilger.kernel@...ger.ca> > Cc: linux-ext4@...r.kernel.org > Cc: Jaegeuk Kim <jaegeuk@...nel.org> > Signed-off-by: Jaegeuk Kim <jaegeuk@...gle.com> > --- > 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 up before making ext4_setup_super() return error code (as your patch could make ext4_fill_super() return SB_RDONLY under some circumstances). > @@ -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; Honza -- Jan Kara <jack@...e.com> SUSE Labs, CR
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