4.9-stable review patch. If anyone has any objections, please let me know.
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From: zhangyi (F) yi.zhang@huawei.com
commit 5e86bdda41534e17621d5a071b294943cae4376e upstream.
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 Cc: Jari Ruusu jari.ruusu@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/indirect.c | 47 ++++++++++++++++++++++------------------------- 1 file changed, 22 insertions(+), 25 deletions(-)
--- a/fs/ext4/indirect.c +++ b/fs/ext4/indirect.c @@ -1217,6 +1217,7 @@ int ext4_ind_remove_space(handle_t *hand 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; @@ -1258,7 +1259,7 @@ int ext4_ind_remove_space(handle_t *hand }
- 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 */ @@ -1283,13 +1284,11 @@ int ext4_ind_remove_space(handle_t *hand 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) { /* @@ -1319,16 +1318,14 @@ 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) { @@ -1385,15 +1382,7 @@ 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; }
/* @@ -1408,8 +1397,6 @@ 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) { @@ -1417,11 +1404,21 @@ 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: @@ -1429,7 +1426,7 @@ 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); @@ -1437,7 +1434,7 @@ do_indirects: } 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); @@ -1445,7 +1442,7 @@ do_indirects: } 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); @@ -1454,5 +1451,5 @@ do_indirects: case EXT4_TIND_BLOCK: ; } - return 0; + goto cleanup; }