minor-cleanup-of-ext4_da_reserve_space

   1 ext4: minor cleanup of ext4_da_reserve_space()
   2
   3 From: Eric Whitney <enwlinux@gmail.com>
   4
   5 Remove outdated comments and dead code from ext4_da_reserve_space.
   6 Clean up its trace point, and relocate it to make it more useful.
   7
   8 While we're at it, fix a nearby conditional used to determine if
   9 we have a non-bigalloc file system.  It doesn't match usage elsewhere
  10 in the code, and misleadingly suggests that an s_cluster_ratio value
  11 of 0 would be legal.
  12
  13 Signed-off-by: Eric Whitney <enwlinux@gmail.com>
  14 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  15 ---
  16  fs/ext4/inode.c             | 22 +++++-----------------
  17  include/trace/events/ext4.h | 10 ++++------
  18  2 files changed, 9 insertions(+), 23 deletions(-)
  19
  20 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  21 index 7eb70b7..fecc1d0 100644
  22 --- a/fs/ext4/inode.c
  23 +++ b/fs/ext4/inode.c
  24 @@ -1262,13 +1262,12 @@ static int ext4_journalled_write_end(struct file *file,
  25  }
  26
  27  /*
  28 - * Reserve a single cluster located at lblock
  29 + * Reserve space for a single cluster
  30   */
  31 -static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
  32 +static int ext4_da_reserve_space(struct inode *inode)
  33  {
  34         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  35         struct ext4_inode_info *ei = EXT4_I(inode);
  36 -       unsigned int md_needed;
  37         int ret;
  38
  39         /*
  40 @@ -1280,25 +1279,14 @@ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
  41         if (ret)
  42                 return ret;
  43
  44 -       /*
  45 -        * recalculate the amount of metadata blocks to reserve
  46 -        * in order to allocate nrblocks
  47 -        * worse case is one extent per block
  48 -        */
  49         spin_lock(&ei->i_block_reservation_lock);
  50 -       /*
  51 -        * ext4_calc_metadata_amount() has side effects, which we have
  52 -        * to be prepared undo if we fail to claim space.
  53 -        */
  54 -       md_needed = 0;
  55 -       trace_ext4_da_reserve_space(inode, 0);
  56 -
  57         if (ext4_claim_free_clusters(sbi, 1, 0)) {
  58                 spin_unlock(&ei->i_block_reservation_lock);
  59                 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
  60                 return -ENOSPC;
  61         }
  62         ei->i_reserved_data_blocks++;
  63 +       trace_ext4_da_reserve_space(inode);
  64         spin_unlock(&ei->i_block_reservation_lock);
  65
  66         return 0;       /* success */
  67 @@ -1567,9 +1555,9 @@ add_delayed:
  68                  * then we don't need to reserve it again. However we still need
  69                  * to reserve metadata for every block we're going to write.
  70                  */
  71 -               if (EXT4_SB(inode->i_sb)->s_cluster_ratio <= 1 ||
  72 +               if (EXT4_SB(inode->i_sb)->s_cluster_ratio == 1 ||
  73                     !ext4_find_delalloc_cluster(inode, map->m_lblk)) {
  74 -                       ret = ext4_da_reserve_space(inode, iblock);
  75 +                       ret = ext4_da_reserve_space(inode);
  76                         if (ret) {
  77                                 /* not enough space to reserve */
  78                                 retval = ret;
  79 diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
  80 index 6e5abd6..6ed16df 100644
  81 --- a/include/trace/events/ext4.h
  82 +++ b/include/trace/events/ext4.h
  83 @@ -1185,15 +1185,14 @@ TRACE_EVENT(ext4_da_update_reserve_space,
  84  );
  85
  86  TRACE_EVENT(ext4_da_reserve_space,
  87 -       TP_PROTO(struct inode *inode, int md_needed),
  88 +       TP_PROTO(struct inode *inode),
  89
  90 -       TP_ARGS(inode, md_needed),
  91 +       TP_ARGS(inode),
  92
  93         TP_STRUCT__entry(
  94                 __field(        dev_t,  dev                     )
  95                 __field(        ino_t,  ino                     )
  96                 __field(        __u64,  i_blocks                )
  97 -               __field(        int,    md_needed               )
  98                 __field(        int,    reserved_data_blocks    )
  99                 __field(        int,    reserved_meta_blocks    )
 100                 __field(        __u16,  mode                    )
 101 @@ -1203,18 +1202,17 @@ TRACE_EVENT(ext4_da_reserve_space,
 102                 __entry->dev    = inode->i_sb->s_dev;
 103                 __entry->ino    = inode->i_ino;
 104                 __entry->i_blocks = inode->i_blocks;
 105 -               __entry->md_needed = md_needed;
 106                 __entry->reserved_data_blocks = EXT4_I(inode)->i_reserved_data_blocks;
 107                 __entry->reserved_meta_blocks = EXT4_I(inode)->i_reserved_meta_blocks;
 108                 __entry->mode   = inode->i_mode;
 109         ),
 110
 111 -       TP_printk("dev %d,%d ino %lu mode 0%o i_blocks %llu md_needed %d "
 112 +       TP_printk("dev %d,%d ino %lu mode 0%o i_blocks %llu "
 113                   "reserved_data_blocks %d reserved_meta_blocks %d",
 114                   MAJOR(__entry->dev), MINOR(__entry->dev),
 115                   (unsigned long) __entry->ino,
 116                   __entry->mode, __entry->i_blocks,
 117 -                 __entry->md_needed, __entry->reserved_data_blocks,
 118 +                 __entry->reserved_data_blocks,
 119                   __entry->reserved_meta_blocks)
 120  );
 121
 122 --
 123 2.1.0
 124
 125