ext4: cleanup bh release code in ext4_ind_remove_space()

Currently, we are releasing the indirect buffer where we are done with
it in ext4_ind_remove_space(), so we can see the brelse() and
BUFFER_TRACE() everywhere.  It seems fragile and hard to read, and we
may probably forget to release the buffer some day.  This patch cleans
up the code by putting of the code which releases the buffers to the
end of the function.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 02c39524bda2a76fdf83500752e615c478d59cd2..2024d3fa55044f734b961f3c8818ba3d243260a3 100644 (file)
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -1222,6 +1222,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
        ext4_lblk_t offsets[4], offsets2[4];
        Indirect chain[4], chain2[4];
        Indirect *partial, *partial2;
+       Indirect *p = NULL, *p2 = NULL;
        ext4_lblk_t max_block;
        __le32 nr = 0, nr2 = 0;
        int n = 0, n2 = 0;
@@ -1263,7 +1264,7 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
                }
 
 
-               partial = ext4_find_shared(inode, n, offsets, chain, &nr);
+               partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
                if (nr) {
                        if (partial == chain) {
                                /* Shared branch grows from the inode */
@@ -1288,13 +1289,11 @@ int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
                                partial->p + 1,
                                (__le32 *)partial->bh->b_data+addr_per_block,
                                (chain+n-1) - partial);
-                       BUFFER_TRACE(partial->bh, "call brelse");
-                       brelse(partial->bh);
                        partial--;
                }
 
 end_range:
-               partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
+               partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
                if (nr2) {
                        if (partial2 == chain2) {
                                /*
@@ -1324,16 +1323,14 @@ end_range:
                                           (__le32 *)partial2->bh->b_data,
                                           partial2->p,
                                           (chain2+n2-1) - partial2);
-                       BUFFER_TRACE(partial2->bh, "call brelse");
-                       brelse(partial2->bh);
                        partial2--;
                }
                goto do_indirects;
        }
 
        /* Punch happened within the same level (n == n2) */
-       partial = ext4_find_shared(inode, n, offsets, chain, &nr);
-       partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
+       partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
+       partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
 
        /* Free top, but only if partial2 isn't its subtree. */
        if (nr) {
@@ -1390,15 +1387,7 @@ end_range:
                                           partial->p + 1,
                                           partial2->p,
                                           (chain+n-1) - partial);
-                       while (partial > chain) {
-                               BUFFER_TRACE(partial->bh, "call brelse");
-                               brelse(partial->bh);
-                       }
-                       while (partial2 > chain2) {
-                               BUFFER_TRACE(partial2->bh, "call brelse");
-                               brelse(partial2->bh);
-                       }
-                       return 0;
+                       goto cleanup;
                }
 
                /*
@@ -1413,8 +1402,6 @@ end_range:
                                           partial->p + 1,
                                           (__le32 *)partial->bh->b_data+addr_per_block,
                                           (chain+n-1) - partial);
-                       BUFFER_TRACE(partial->bh, "call brelse");
-                       brelse(partial->bh);
                        partial--;
                }
                if (partial2 > chain2 && depth2 <= depth) {
@@ -1422,11 +1409,21 @@ end_range:
                                           (__le32 *)partial2->bh->b_data,
                                           partial2->p,
                                           (chain2+n2-1) - partial2);
-                       BUFFER_TRACE(partial2->bh, "call brelse");
-                       brelse(partial2->bh);
                        partial2--;
                }
        }
+
+cleanup:
+       while (p && p > chain) {
+               BUFFER_TRACE(p->bh, "call brelse");
+               brelse(p->bh);
+               p--;
+       }
+       while (p2 && p2 > chain2) {
+               BUFFER_TRACE(p2->bh, "call brelse");
+               brelse(p2->bh);
+               p2--;
+       }
        return 0;
 
 do_indirects:
@@ -1434,7 +1431,7 @@ do_indirects:
        switch (offsets[0]) {
        default:
                if (++n >= n2)
-                       return 0;
+                       break;
                nr = i_data[EXT4_IND_BLOCK];
                if (nr) {
                        ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
@@ -1443,7 +1440,7 @@ do_indirects:
                /* fall through */
        case EXT4_IND_BLOCK:
                if (++n >= n2)
-                       return 0;
+                       break;
                nr = i_data[EXT4_DIND_BLOCK];
                if (nr) {
                        ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
@@ -1452,7 +1449,7 @@ do_indirects:
                /* fall through */
        case EXT4_DIND_BLOCK:
                if (++n >= n2)
-                       return 0;
+                       break;
                nr = i_data[EXT4_TIND_BLOCK];
                if (nr) {
                        ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
@@ -1462,5 +1459,5 @@ do_indirects:
        case EXT4_TIND_BLOCK:
                ;
        }
-       return 0;
+       goto cleanup;
 }