handle-errors-on-ext4_commit_super

   1 ext4: handle errors on ext4_commit_super
   2
   3 From: Jaegeuk Kim <jaegeuk@kernel.org>
   4
   5 When remounting ext4 from ro to rw, currently it allows its transition,
   6 even if ext4_commit_super() returns EIO. Even worse thing is, after that,
   7 fs/buffer complains buffer dirty bits like:
   8
   9  Call trace:
  10  [<ffffff9750c259dc>] mark_buffer_dirty+0x184/0x1a4
  11  [<ffffff9750cb398c>] __ext4_handle_dirty_super+0x4c/0xfc
  12  [<ffffff9750c7a9fc>] ext4_file_open+0x154/0x1c0
  13  [<ffffff9750bea51c>] do_dentry_open+0x114/0x2d0
  14  [<ffffff9750bea75c>] vfs_open+0x5c/0x94
  15  [<ffffff9750bf879c>] path_openat+0x668/0xfe8
  16  [<ffffff9750bf8088>] do_filp_open+0x74/0x120
  17  [<ffffff9750beac98>] do_sys_open+0x148/0x254
  18  [<ffffff9750beade0>] SyS_openat+0x10/0x18
  19  [<ffffff9750a83ab0>] el0_svc_naked+0x24/0x28
  20  EXT4-fs (dm-1): previous I/O error to superblock detected
  21  Buffer I/O error on dev dm-1, logical block 0, lost sync page write
  22  EXT4-fs (dm-1): re-mounted. Opts: (null)
  23  Buffer I/O error on dev dm-1, logical block 80, lost async page write
  24
  25 Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
  26 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  27 ---
  28  fs/ext4/super.c | 35 +++++++++++++++++++++--------------
  29  1 file changed, 21 insertions(+), 14 deletions(-)
  30
  31 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
  32 index d6d6e7db73d6..1388e56bb3f5 100644
  33 --- a/fs/ext4/super.c
  34 +++ b/fs/ext4/super.c
  35 @@ -2146,12 +2146,12 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  36                             int read_only)
  37  {
  38         struct ext4_sb_info *sbi = EXT4_SB(sb);
  39 -       int res = 0;
  40 +       int err = 0;
  41
  42         if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
  43                 ext4_msg(sb, KERN_ERR, "revision level too high, "
  44                          "forcing read-only mode");
  45 -               res = SB_RDONLY;
  46 +               err = -EROFS;
  47         }
  48         if (read_only)
  49                 goto done;
  50 @@ -2184,7 +2184,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  51         if (sbi->s_journal)
  52                 ext4_set_feature_journal_needs_recovery(sb);
  53
  54 -       ext4_commit_super(sb, 1);
  55 +       err = ext4_commit_super(sb, 1);
  56  done:
  57         if (test_opt(sb, DEBUG))
  58                 printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
  59 @@ -2196,7 +2196,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  60                         sbi->s_mount_opt, sbi->s_mount_opt2);
  61
  62         cleancache_init_fs(sb);
  63 -       return res;
  64 +       return err;
  65  }
  66
  67  int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
  68 @@ -4254,8 +4254,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  69                 goto failed_mount4;
  70         }
  71
  72 -       if (ext4_setup_super(sb, es, sb_rdonly(sb)))
  73 +       ret = ext4_setup_super(sb, es, sb_rdonly(sb));
  74 +       if (ret == -EROFS) {
  75                 sb->s_flags |= SB_RDONLY;
  76 +               ret = 0;
  77 +       } else if (ret)
  78 +               goto failed_mount4a;
  79
  80         /* determine the minimum size of new large inodes, if present */
  81         if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE &&
  82 @@ -4790,11 +4794,7 @@ static int ext4_commit_super(struct super_block *sb, int sync)
  83                 unlock_buffer(sbh);
  84                 error = __sync_dirty_buffer(sbh,
  85                         REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0));
  86 -               if (error)
  87 -                       return error;
  88 -
  89 -               error = buffer_write_io_error(sbh);
  90 -               if (error) {
  91 +               if (buffer_write_io_error(sbh)) {
  92                         ext4_msg(sb, KERN_ERR, "I/O error while writing "
  93                                "superblock");
  94                         clear_buffer_write_io_error(sbh);
  95 @@ -5195,8 +5195,12 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
  96                         if (sbi->s_journal)
  97                                 ext4_clear_journal_err(sb, es);
  98                         sbi->s_mount_state = le16_to_cpu(es->s_state);
  99 -                       if (!ext4_setup_super(sb, es, 0))
 100 -                               sb->s_flags &= ~SB_RDONLY;
 101 +
 102 +                       err = ext4_setup_super(sb, es, 0);
 103 +                       if (err)
 104 +                               goto restore_opts;
 105 +
 106 +                       sb->s_flags &= ~SB_RDONLY;
 107                         if (ext4_has_feature_mmp(sb))
 108                                 if (ext4_multi_mount_protect(sb,
 109                                                 le64_to_cpu(es->s_mmp_block))) {
 110 @@ -5220,8 +5224,11 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 111         }
 112
 113         ext4_setup_system_zone(sb);
 114 -       if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY))
 115 -               ext4_commit_super(sb, 1);
 116 +       if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) {
 117 +               err = ext4_commit_super(sb, 1);
 118 +               if (err)
 119 +                       goto restore_opts;
 120 +       }
 121
 122  #ifdef CONFIG_QUOTA
 123         /* Release old quota file names */