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| author | Chris Mason <chris.mason@oracle.com> | 2012-04-27 14:31:29 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2012-04-27 14:51:05 -0400 |
| commit | dc7fdde39e4962b1a88741f7eba2a6b3be1285d8 (patch) | |
| tree | 97cd8b1f9d8c0682c64303d45de1fb55925abcdf | |
| parent | fede766f28dd766d4e8feb321fdb19edb21ef6fb (diff) | |
| download | blackbird-op-linux-dc7fdde39e4962b1a88741f7eba2a6b3be1285d8.tar.gz blackbird-op-linux-dc7fdde39e4962b1a88741f7eba2a6b3be1285d8.zip | |
Btrfs: reduce lock contention during extent insertion
We're spending huge amounts of time on lock contention during
end_io processing because we unconditionally assume we are overwriting
an existing extent in the file for each IO.
This checks to see if we are outside i_size, and if so, it uses a
less expensive readonly search of the btree to look for existing
extents.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
| -rw-r--r-- | fs/btrfs/file.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index d83260d7498f..53bf2d764bbc 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -567,6 +567,7 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode, int extent_type; int recow; int ret; + int modify_tree = -1; if (drop_cache) btrfs_drop_extent_cache(inode, start, end - 1, 0); @@ -575,10 +576,13 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode, if (!path) return -ENOMEM; + if (start >= BTRFS_I(inode)->disk_i_size) + modify_tree = 0; + while (1) { recow = 0; ret = btrfs_lookup_file_extent(trans, root, path, ino, - search_start, -1); + search_start, modify_tree); if (ret < 0) break; if (ret > 0 && path->slots[0] > 0 && search_start == start) { @@ -634,7 +638,8 @@ next_slot: } search_start = max(key.offset, start); - if (recow) { + if (recow || !modify_tree) { + modify_tree = -1; btrfs_release_path(path); continue; } |
