Btrfs: optimize btrfs_lookup_extent_info()
PATCH 1/1 Btrfs: optimize btrfs_lookup_extent_info()
If we're looking for a metadata item in the tree and the search fails with return value of 1, and the slot doesn't point to the first item in the leaf, check if the previous item in the leaf corresponds to an extent item for the same object id - if it does, then don't do another tree search to get it.
--- fs/btrfs/extent-tree.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)
fs/btrfs/extent-tree.c +16 -4
@@ -771,10 +771,22 @@ again: goto out_free;if (ret >0 && metadata && key.type ==BTRFS_METADATA_ITEM_KEY ) { - key.type =BTRFS_EXTENT_ITEM_KEY ; - key.offset = root->leafsize; -btrfs_release_path (path); - goto again; +if (path->slots[0 ]) { + path->slots[0 ]--; +btrfs_item_key_to_cpu (path->nodes[0 ], &key, + path->slots[0 ]); +if (key.objectid == bytenr && + key.type ==BTRFS_EXTENT_ITEM_KEY && + key.offset == root->leafsize) + ret =0 ; + } +if (ret) { + key.objectid = bytenr; + key.type =BTRFS_EXTENT_ITEM_KEY ; + key.offset = root->leafsize; +btrfs_release_path (path); + goto again; + } }if (ret ==0 ) {
Signature · 1 line
1.7.9.5
PATCH v2 1/1 Btrfs: optimize btrfs_lookup_extent_info()
If we're looking for a metadata item in the tree and the search fails with return value of 1, and the slot doesn't point to the first item in the leaf, check if the previous item in the leaf corresponds to an extent item for the same object id - if it does, then don't do another tree search to get it.
This optimization is already done by btrfs-progs.
V2: updated commit message.
--- fs/btrfs/extent-tree.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
fs/btrfs/extent-tree.c +17 -4
@@ -771,10 +771,23 @@ again: goto out_free;if (ret >0 && metadata && key.type ==BTRFS_METADATA_ITEM_KEY ) { - key.type =BTRFS_EXTENT_ITEM_KEY ; - key.offset = root->leafsize; -btrfs_release_path (path); - goto again; + metadata =0 ; +if (path->slots[0 ]) { + path->slots[0 ]--; +btrfs_item_key_to_cpu (path->nodes[0 ], &key, + path->slots[0 ]); +if (key.objectid == bytenr && + key.type ==BTRFS_EXTENT_ITEM_KEY && + key.offset == root->leafsize) + ret =0 ; + } +if (ret) { + key.objectid = bytenr; + key.type =BTRFS_EXTENT_ITEM_KEY ; + key.offset = root->leafsize; +btrfs_release_path (path); + goto again; + } }if (ret ==0 ) {
Signature · 1 line
1.7.9.5
PATCH v3 1/1 Btrfs: optimize btrfs_lookup_extent_info()
In reply to Filipe David Borba MananaIf we're looking for a metadata item in the tree and the search fails with return value of 1, and the slot doesn't point to the first item in the leaf, check if the previous item in the leaf corresponds to an extent item for the same object id - if it does, then don't do another tree search to get it.
This optimization is already done by btrfs-progs.
---
V2: updated commit message to mention this is already done in
btrfs-progs.
V3: moved version information out of the commit message, as
David Sterba notified me this is the correct way of adding patch version information.
fs/btrfs/extent-tree.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
fs/btrfs/extent-tree.c +17 -4
@@ -771,10 +771,23 @@ again: goto out_free;if (ret >0 && metadata && key.type ==BTRFS_METADATA_ITEM_KEY ) { - key.type =BTRFS_EXTENT_ITEM_KEY ; - key.offset = root->leafsize; -btrfs_release_path (path); - goto again; + metadata =0 ; +if (path->slots[0 ]) { + path->slots[0 ]--; +btrfs_item_key_to_cpu (path->nodes[0 ], &key, + path->slots[0 ]); +if (key.objectid == bytenr && + key.type ==BTRFS_EXTENT_ITEM_KEY && + key.offset == root->leafsize) + ret =0 ; + } +if (ret) { + key.objectid = bytenr; + key.type =BTRFS_EXTENT_ITEM_KEY ; + key.offset = root->leafsize; +btrfs_release_path (path); + goto again; + } }if (ret ==0 ) {
Signature · 1 line
1.7.9.5