queue-4.19/ext4-cleanup-bh-release-code-in-ext4_ind_remove_space.patch

   1 From 5e86bdda41534e17621d5a071b294943cae4376e Mon Sep 17 00:00:00 2001
   2 From: "zhangyi (F)" <yi.zhang@huawei.com>
   3 Date: Sat, 23 Mar 2019 11:56:01 -0400
   4 Subject: ext4: cleanup bh release code in ext4_ind_remove_space()
   5
   6 From: zhangyi (F) <yi.zhang@huawei.com>
   7
   8 commit 5e86bdda41534e17621d5a071b294943cae4376e upstream.
   9
  10 Currently, we are releasing the indirect buffer where we are done with
  11 it in ext4_ind_remove_space(), so we can see the brelse() and
  12 BUFFER_TRACE() everywhere.  It seems fragile and hard to read, and we
  13 may probably forget to release the buffer some day.  This patch cleans
  14 up the code by putting of the code which releases the buffers to the
  15 end of the function.
  16
  17 Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
  18 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  19 Reviewed-by: Jan Kara <jack@suse.cz>
  20 Cc: Jari Ruusu <jari.ruusu@gmail.com>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  22
  23 ---
  24  fs/ext4/indirect.c |   47 ++++++++++++++++++++++-------------------------
  25  1 file changed, 22 insertions(+), 25 deletions(-)
  26
  27 --- a/fs/ext4/indirect.c
  28 +++ b/fs/ext4/indirect.c
  29 @@ -1219,6 +1219,7 @@ int ext4_ind_remove_space(handle_t *hand
  30         ext4_lblk_t offsets[4], offsets2[4];
  31         Indirect chain[4], chain2[4];
  32         Indirect *partial, *partial2;
  33 +       Indirect *p = NULL, *p2 = NULL;
  34         ext4_lblk_t max_block;
  35         __le32 nr = 0, nr2 = 0;
  36         int n = 0, n2 = 0;
  37 @@ -1260,7 +1261,7 @@ int ext4_ind_remove_space(handle_t *hand
  38                 }
  39
  40
  41 -               partial = ext4_find_shared(inode, n, offsets, chain, &nr);
  42 +               partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
  43                 if (nr) {
  44                         if (partial == chain) {
  45                                 /* Shared branch grows from the inode */
  46 @@ -1285,13 +1286,11 @@ int ext4_ind_remove_space(handle_t *hand
  47                                 partial->p + 1,
  48                                 (__le32 *)partial->bh->b_data+addr_per_block,
  49                                 (chain+n-1) - partial);
  50 -                       BUFFER_TRACE(partial->bh, "call brelse");
  51 -                       brelse(partial->bh);
  52                         partial--;
  53                 }
  54
  55  end_range:
  56 -               partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
  57 +               partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
  58                 if (nr2) {
  59                         if (partial2 == chain2) {
  60                                 /*
  61 @@ -1321,16 +1320,14 @@ end_range:
  62                                            (__le32 *)partial2->bh->b_data,
  63                                            partial2->p,
  64                                            (chain2+n2-1) - partial2);
  65 -                       BUFFER_TRACE(partial2->bh, "call brelse");
  66 -                       brelse(partial2->bh);
  67                         partial2--;
  68                 }
  69                 goto do_indirects;
  70         }
  71
  72         /* Punch happened within the same level (n == n2) */
  73 -       partial = ext4_find_shared(inode, n, offsets, chain, &nr);
  74 -       partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
  75 +       partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
  76 +       partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
  77
  78         /* Free top, but only if partial2 isn't its subtree. */
  79         if (nr) {
  80 @@ -1387,15 +1384,7 @@ end_range:
  81                                            partial->p + 1,
  82                                            partial2->p,
  83                                            (chain+n-1) - partial);
  84 -                       while (partial > chain) {
  85 -                               BUFFER_TRACE(partial->bh, "call brelse");
  86 -                               brelse(partial->bh);
  87 -                       }
  88 -                       while (partial2 > chain2) {
  89 -                               BUFFER_TRACE(partial2->bh, "call brelse");
  90 -                               brelse(partial2->bh);
  91 -                       }
  92 -                       return 0;
  93 +                       goto cleanup;
  94                 }
  95
  96                 /*
  97 @@ -1410,8 +1399,6 @@ end_range:
  98                                            partial->p + 1,
  99                                            (__le32 *)partial->bh->b_data+addr_per_block,
 100                                            (chain+n-1) - partial);
 101 -                       BUFFER_TRACE(partial->bh, "call brelse");
 102 -                       brelse(partial->bh);
 103                         partial--;
 104                 }
 105                 if (partial2 > chain2 && depth2 <= depth) {
 106 @@ -1419,11 +1406,21 @@ end_range:
 107                                            (__le32 *)partial2->bh->b_data,
 108                                            partial2->p,
 109                                            (chain2+n2-1) - partial2);
 110 -                       BUFFER_TRACE(partial2->bh, "call brelse");
 111 -                       brelse(partial2->bh);
 112                         partial2--;
 113                 }
 114         }
 115 +
 116 +cleanup:
 117 +       while (p && p > chain) {
 118 +               BUFFER_TRACE(p->bh, "call brelse");
 119 +               brelse(p->bh);
 120 +               p--;
 121 +       }
 122 +       while (p2 && p2 > chain2) {
 123 +               BUFFER_TRACE(p2->bh, "call brelse");
 124 +               brelse(p2->bh);
 125 +               p2--;
 126 +       }
 127         return 0;
 128
 129  do_indirects:
 130 @@ -1431,7 +1428,7 @@ do_indirects:
 131         switch (offsets[0]) {
 132         default:
 133                 if (++n >= n2)
 134 -                       return 0;
 135 +                       break;
 136                 nr = i_data[EXT4_IND_BLOCK];
 137                 if (nr) {
 138                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
 139 @@ -1439,7 +1436,7 @@ do_indirects:
 140                 }
 141         case EXT4_IND_BLOCK:
 142                 if (++n >= n2)
 143 -                       return 0;
 144 +                       break;
 145                 nr = i_data[EXT4_DIND_BLOCK];
 146                 if (nr) {
 147                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
 148 @@ -1447,7 +1444,7 @@ do_indirects:
 149                 }
 150         case EXT4_DIND_BLOCK:
 151                 if (++n >= n2)
 152 -                       return 0;
 153 +                       break;
 154                 nr = i_data[EXT4_TIND_BLOCK];
 155                 if (nr) {
 156                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
 157 @@ -1456,5 +1453,5 @@ do_indirects:
 158         case EXT4_TIND_BLOCK:
 159                 ;
 160         }
 161 -       return 0;
 162 +       goto cleanup;
 163  }