create-EXT4_MAX_BLOCKS-macro

   1 ext4: create EXT4_MAX_BLOCKS() macro
   2
   3 From: Fabian Frederick <fabf@skynet.be>
   4
   5 Create a macro to calculate length + offset -> maximum blocks
   6 This adds more readability.
   7
   8 Signed-off-by: Fabian Frederick <fabf@skynet.be>
   9 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  10 ---
  11  fs/ext4/ext4.h    |  3 +++
  12  fs/ext4/extents.c | 15 +++------------
  13  fs/ext4/file.c    |  3 +--
  14  3 files changed, 7 insertions(+), 14 deletions(-)
  15
  16 diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
  17 index ea31931..6e98f3f 100644
  18 --- a/fs/ext4/ext4.h
  19 +++ b/fs/ext4/ext4.h
  20 @@ -262,6 +262,9 @@ struct ext4_io_submit {
  21                                  (s)->s_first_ino)
  22  #endif
  23  #define EXT4_BLOCK_ALIGN(size, blkbits)                ALIGN((size), (1 << (blkbits)))
  24 +#define EXT4_MAX_BLOCKS(size, offset, blkbits) \
  25 +       ((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
  26 +                                                                 blkbits))
  27
  28  /* Translate a block number to a cluster number */
  29  #define EXT4_B2C(sbi, blk)     ((blk) >> (sbi)->s_cluster_bits)
  30 diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
  31 index 4f1cca8..ac54907 100644
  32 --- a/fs/ext4/extents.c
  33 +++ b/fs/ext4/extents.c
  34 @@ -4960,13 +4960,8 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
  35
  36         trace_ext4_fallocate_enter(inode, offset, len, mode);
  37         lblk = offset >> blkbits;
  38 -       /*
  39 -        * We can't just convert len to max_blocks because
  40 -        * If blocksize = 4096 offset = 3072 and len = 2048
  41 -        */
  42 -       max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
  43 -               - lblk;
  44
  45 +       max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
  46         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
  47         if (mode & FALLOC_FL_KEEP_SIZE)
  48                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
  49 @@ -5029,12 +5024,8 @@ int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
  50         unsigned int credits, blkbits = inode->i_blkbits;
  51
  52         map.m_lblk = offset >> blkbits;
  53 -       /*
  54 -        * We can't just convert len to max_blocks because
  55 -        * If blocksize = 4096 offset = 3072 and len = 2048
  56 -        */
  57 -       max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
  58 -                     map.m_lblk);
  59 +       max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
  60 +
  61         /*
  62          * This is somewhat ugly but the idea is clear: When transaction is
  63          * reserved, everything goes into it. Otherwise we rather start several
  64 diff --git a/fs/ext4/file.c b/fs/ext4/file.c
  65 index 261ac37..34acda7 100644
  66 --- a/fs/ext4/file.c
  67 +++ b/fs/ext4/file.c
  68 @@ -144,8 +144,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  69                         int err, len;
  70
  71                         map.m_lblk = pos >> blkbits;
  72 -                       map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
  73 -                               - map.m_lblk;
  74 +                       map.m_len = EXT4_MAX_BLOCKS(length, pos, blkbits);
  75                         len = map.m_len;
  76
  77                         err = ext4_map_blocks(NULL, inode, &map, 0);
  78 --
  79 2.8.1
  80
  81