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authorJosef Bacik <jbacik@fusionio.com>2013-06-17 17:44:48 (GMT)
committerJosef Bacik <jbacik@fusionio.com>2013-07-01 12:52:32 (GMT)
commitbdf7c00e8f56386dd1df545b37cf59d55ce4216d (patch)
treef8fbe2f4b5c5dbd9c6b9a4d79bd3e729a874e7ec /fs
parentfdf8e2ea3cba9ef03087482b11258d844d6cbea3 (diff)
downloadlinux-fsl-qoriq-bdf7c00e8f56386dd1df545b37cf59d55ce4216d.tar.xz
Btrfs: optimize read_block_for_search
This patch does two things, first it only does one call to btrfs_buffer_uptodate() with the gen specified instead of once with 0 and then again with gen specified. The other thing is to call btrfs_read_buffer() on the buffer we've found instead of dropping it and then calling read_tree_block(). This will keep us from doing yet another radix tree lookup for a buffer we've already found. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ctree.c47
1 files changed, 20 insertions, 27 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 1c9dc71..c85cde7 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2359,35 +2359,28 @@ read_block_for_search(struct btrfs_trans_handle *trans,
tmp = btrfs_find_tree_block(root, blocknr, blocksize);
if (tmp) {
/* first we do an atomic uptodate check */
- if (btrfs_buffer_uptodate(tmp, 0, 1) > 0) {
- if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
- /*
- * we found an up to date block without
- * sleeping, return
- * right away
- */
- *eb_ret = tmp;
- return 0;
- }
- /* the pages were up to date, but we failed
- * the generation number check. Do a full
- * read for the generation number that is correct.
- * We must do this without dropping locks so
- * we can trust our generation number
- */
- free_extent_buffer(tmp);
- btrfs_set_path_blocking(p);
+ if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
+ *eb_ret = tmp;
+ return 0;
+ }
- /* now we're allowed to do a blocking uptodate check */
- tmp = read_tree_block(root, blocknr, blocksize, gen);
- if (tmp && btrfs_buffer_uptodate(tmp, gen, 0) > 0) {
- *eb_ret = tmp;
- return 0;
- }
- free_extent_buffer(tmp);
- btrfs_release_path(p);
- return -EIO;
+ /* the pages were up to date, but we failed
+ * the generation number check. Do a full
+ * read for the generation number that is correct.
+ * We must do this without dropping locks so
+ * we can trust our generation number
+ */
+ btrfs_set_path_blocking(p);
+
+ /* now we're allowed to do a blocking uptodate check */
+ ret = btrfs_read_buffer(tmp, gen);
+ if (!ret) {
+ *eb_ret = tmp;
+ return 0;
}
+ free_extent_buffer(tmp);
+ btrfs_release_path(p);
+ return -EIO;
}
/*