add-gfp-version-for-sb_getblk

   1 bufferhead: Add _gfp version for sb_getblk()
   2
   3 From: Nikolay Borisov <kernel@kyup.com>
   4
   5 sb_getblk() is used during ext4 (and possibly other FSes) writeback
   6 paths. Sometimes such path require allocating memory and guaranteeing
   7 that such allocation won't block. Currently, however, there is no way
   8 to provide user flags for sb_getblk which could lead to deadlocks.
   9
  10 This patch implements a sb_getblk_gfp with the only difference it can
  11 accept user-provided GFP flags.
  12
  13 Signed-off-by: Nikolay Borisov <kernel@kyup.com>
  14 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  15 Cc: stable@vger.kernel.org
  16 ---
  17
  18 As per the discussion in this thread (http://marc.info/?l=linux-ext4&m=143563347324528&w=2)
  19 here are the patches which hopefully implement Ted's suggestion.
  20
  21  include/linux/buffer_head.h |    7 +++++++
  22  1 files changed, 7 insertions(+), 0 deletions(-)
  23
  24 diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
  25 index 73b4522..e6797de 100644
  26 --- a/include/linux/buffer_head.h
  27 +++ b/include/linux/buffer_head.h
  28 @@ -317,6 +317,13 @@ sb_getblk(struct super_block *sb, sector_t block)
  29         return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
  30  }
  31
  32 +
  33 +static inline struct buffer_head *
  34 +sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp)
  35 +{
  36 +       return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp);
  37 +}
  38 +
  39  static inline struct buffer_head *
  40  sb_find_get_block(struct super_block *sb, sector_t block)
  41  {
  42 --
  43 1.7.1
  44
  45