convert-ext4_getblk-to-use-the-ERR_PTR-convention

   1 ext4: convert ext4_getblk() to use the ERR_PTR convention
   2
   3 From: Theodore Ts'o <tytso@mit.edu>
   4
   5 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
   6 ---
   7  fs/ext4/ext4.h  |  3 +--
   8  fs/ext4/inode.c | 51 +++++++++++++++++++++++++--------------------------
   9  fs/ext4/namei.c |  9 ++++-----
  10  3 files changed, 30 insertions(+), 33 deletions(-)
  11
  12 diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
  13 index b0c225c..8009077 100644
  14 --- a/fs/ext4/ext4.h
  15 +++ b/fs/ext4/ext4.h
  16 @@ -2086,8 +2086,7 @@ extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
  17  extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
  18
  19  /* inode.c */
  20 -struct buffer_head *ext4_getblk(handle_t *, struct inode *,
  21 -                                               ext4_lblk_t, int, int *);
  22 +struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
  23  struct buffer_head *ext4_bread(handle_t *, struct inode *,
  24                                                 ext4_lblk_t, int, int *);
  25  int ext4_get_block_write(struct inode *inode, sector_t iblock,
  26 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  27 index 3aa26e9..0dfc1cd 100644
  28 --- a/fs/ext4/inode.c
  29 +++ b/fs/ext4/inode.c
  30 @@ -734,11 +734,11 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
  31   * `handle' can be NULL if create is zero
  32   */
  33  struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
  34 -                               ext4_lblk_t block, int create, int *errp)
  35 +                               ext4_lblk_t block, int create)
  36  {
  37         struct ext4_map_blocks map;
  38         struct buffer_head *bh;
  39 -       int fatal = 0, err;
  40 +       int err;
  41
  42         J_ASSERT(handle != NULL || create == 0);
  43
  44 @@ -747,21 +747,14 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
  45         err = ext4_map_blocks(handle, inode, &map,
  46                               create ? EXT4_GET_BLOCKS_CREATE : 0);
  47
  48 -       /* ensure we send some value back into *errp */
  49 -       *errp = 0;
  50 -
  51 -       if (create && err == 0)
  52 -               err = -ENOSPC;  /* should never happen */
  53 +       if (err == 0)
  54 +               return create ? ERR_PTR(-ENOSPC) : NULL;
  55         if (err < 0)
  56 -               *errp = err;
  57 -       if (err <= 0)
  58 -               return NULL;
  59 +               return ERR_PTR(err);
  60
  61         bh = sb_getblk(inode->i_sb, map.m_pblk);
  62 -       if (unlikely(!bh)) {
  63 -               *errp = -ENOMEM;
  64 -               return NULL;
  65 -       }
  66 +       if (unlikely(!bh))
  67 +               return ERR_PTR(-ENOMEM);
  68         if (map.m_flags & EXT4_MAP_NEW) {
  69                 J_ASSERT(create != 0);
  70                 J_ASSERT(handle != NULL);
  71 @@ -775,25 +768,26 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
  72                  */
  73                 lock_buffer(bh);
  74                 BUFFER_TRACE(bh, "call get_create_access");
  75 -               fatal = ext4_journal_get_create_access(handle, bh);
  76 -               if (!fatal && !buffer_uptodate(bh)) {
  77 +               err = ext4_journal_get_create_access(handle, bh);
  78 +               if (unlikely(err)) {
  79 +                       unlock_buffer(bh);
  80 +                       goto errout;
  81 +               }
  82 +               if (!buffer_uptodate(bh)) {
  83                         memset(bh->b_data, 0, inode->i_sb->s_blocksize);
  84                         set_buffer_uptodate(bh);
  85                 }
  86                 unlock_buffer(bh);
  87                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
  88                 err = ext4_handle_dirty_metadata(handle, inode, bh);
  89 -               if (!fatal)
  90 -                       fatal = err;
  91 -       } else {
  92 +               if (unlikely(err))
  93 +                       goto errout;
  94 +       } else
  95                 BUFFER_TRACE(bh, "not a new buffer");
  96 -       }
  97 -       if (fatal) {
  98 -               *errp = fatal;
  99 -               brelse(bh);
 100 -               bh = NULL;
 101 -       }
 102         return bh;
 103 +errout:
 104 +       brelse(bh);
 105 +       return ERR_PTR(err);
 106  }
 107
 108  struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 109 @@ -801,7 +795,12 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
 110  {
 111         struct buffer_head *bh;
 112
 113 -       bh = ext4_getblk(handle, inode, block, create, err);
 114 +       *err = 0;
 115 +       bh = ext4_getblk(handle, inode, block, create);
 116 +       if (IS_ERR(bh)) {
 117 +               *err = PTR_ERR(bh);
 118 +               return NULL;
 119 +       }
 120         if (!bh)
 121                 return bh;
 122         if (buffer_uptodate(bh))
 123 diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
 124 index 1421ec1..26f114b 100644
 125 --- a/fs/ext4/namei.c
 126 +++ b/fs/ext4/namei.c
 127 @@ -1226,8 +1226,7 @@ static struct buffer_head * ext4_find_entry (struct inode *dir,
 128                                    buffer */
 129         int num = 0;
 130         ext4_lblk_t  nblocks;
 131 -       int i, err = 0;
 132 -       int namelen;
 133 +       int i, namelen;
 134
 135         *res_dir = NULL;
 136         sb = dir->i_sb;
 137 @@ -1293,10 +1292,10 @@ restart:
 138                                         break;
 139                                 }
 140                                 num++;
 141 -                               bh = ext4_getblk(NULL, dir, b++, 0, &err);
 142 -                               if (unlikely(err)) {
 143 +                               bh = ext4_getblk(NULL, dir, b++, 0);
 144 +                               if (unlikely(IS_ERR(bh))) {
 145                                         if (ra_max == 0)
 146 -                                               return ERR_PTR(err);
 147 +                                               return bh;
 148                                         break;
 149                                 }
 150                                 bh_use[ra_max] = bh;
 151 --
 152 2.1.0
 153