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authorJosef Bacik <josef@redhat.com>2010-02-02 20:50:10 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-13 13:20:11 -0700
commit8fde9c08a05eeec46081864307877d361fdbaafa (patch)
tree24446819bf81a53f9c02f4f666bf0b93ea9f5945
parentfa3c9782cdbb89ba2139e7c2edc1ae562582a6ba (diff)
Btrfs: do not try and lookup the file extent when finishing ordered io
commit efd049fb26a162c3830fd3cb1001fdc09b147f3b upstream. When running the following fio job [torrent] filename=torrent-test rw=randwrite size=4g filesize=4g bs=4k ioengine=sync you would see long stalls where no work was being done. That is because we were doing all this extra work to read in the file extent outside of the transaction, however in the random io case this ends up hurting us because the file extents are not there to begin with. So axe this logic, since we end up reading in the file extent when we go to update it anyway. This took the fio job from 11 mb/s with several ~10 second stalls to 24 mb/s to a couple of 1-2 second stalls. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com> Acked-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/btrfs/inode.c46
1 files changed, 2 insertions, 44 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a6d79c7731e8..8fa67e096305 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1680,24 +1680,6 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
* before we start the transaction. It limits the amount of btree
* reads required while inside the transaction.
*/
-static noinline void reada_csum(struct btrfs_root *root,
- struct btrfs_path *path,
- struct btrfs_ordered_extent *ordered_extent)
-{
- struct btrfs_ordered_sum *sum;
- u64 bytenr;
-
- sum = list_entry(ordered_extent->list.next, struct btrfs_ordered_sum,
- list);
- bytenr = sum->sums[0].bytenr;
-
- /*
- * we don't care about the results, the point of this search is
- * just to get the btree leaves into ram
- */
- btrfs_lookup_csum(NULL, root->fs_info->csum_root, path, bytenr, 0);
-}
-
/* as ordered data IO finishes, this gets called so we can finish
* an ordered extent if the range of bytes in the file it covers are
* fully written.
@@ -1708,7 +1690,6 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
struct btrfs_trans_handle *trans;
struct btrfs_ordered_extent *ordered_extent = NULL;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
- struct btrfs_path *path;
int compressed = 0;
int ret;
@@ -1716,32 +1697,9 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
if (!ret)
return 0;
- /*
- * before we join the transaction, try to do some of our IO.
- * This will limit the amount of IO that we have to do with
- * the transaction running. We're unlikely to need to do any
- * IO if the file extents are new, the disk_i_size checks
- * covers the most common case.
- */
- if (start < BTRFS_I(inode)->disk_i_size) {
- path = btrfs_alloc_path();
- if (path) {
- ret = btrfs_lookup_file_extent(NULL, root, path,
- inode->i_ino,
- start, 0);
- ordered_extent = btrfs_lookup_ordered_extent(inode,
- start);
- if (!list_empty(&ordered_extent->list)) {
- btrfs_release_path(root, path);
- reada_csum(root, path, ordered_extent);
- }
- btrfs_free_path(path);
- }
- }
-
- if (!ordered_extent)
- ordered_extent = btrfs_lookup_ordered_extent(inode, start);
+ ordered_extent = btrfs_lookup_ordered_extent(inode, start);
BUG_ON(!ordered_extent);
+
if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
BUG_ON(!list_empty(&ordered_extent->list));
ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);