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Btrfs: make some tree searches in send.c more efficient
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We have this pattern where we do search for a contiguous group of
items in a tree and everytime we find an item, we process it, then
we release our path, increment the offset of the search key, do
another full tree search and repeat these steps until a tree search
can't find more items we're interested in.

Instead of doing these full tree searches after processing each item,
just process the next item/slot in our leaf and don't release the path.
Since all these trees are read only and we always use the commit root
for a search and skip node/leaf locks, we're not affecting concurrency
on the trees.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
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Filipe David Borba Manana authored and Josef Bacik committed Mar 10, 2014
1 parent a0859c0 commit dff6d0a
Showing 1 changed file with 64 additions and 41 deletions.
105 changes: 64 additions & 41 deletions fs/btrfs/send.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2501,17 +2501,26 @@ static int did_create_dir(struct send_ctx *sctx, u64 dir)
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0);
if (ret < 0)
goto out;

while (1) {
ret = btrfs_search_slot_for_read(sctx->send_root, &key, path,
1, 0);
if (ret < 0)
goto out;
if (!ret) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(sctx->send_root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}
if (ret || found_key.objectid != key.objectid ||

btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
goto out;
Expand All @@ -2526,8 +2535,7 @@ static int did_create_dir(struct send_ctx *sctx, u64 dir)
goto out;
}

key.offset = found_key.offset + 1;
btrfs_release_path(path);
path->slots[0]++;
}

out:
Expand Down Expand Up @@ -2693,19 +2701,24 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 send_progress)
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;

while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (!ret) {
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}
if (ret || found_key.objectid != key.objectid ||
found_key.type != key.type) {
btrfs_item_key_to_cpu(path->nodes[0], &found_key,
path->slots[0]);
if (found_key.objectid != key.objectid ||
found_key.type != key.type)
break;
}

di = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_dir_item);
Expand All @@ -2716,8 +2729,7 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 send_progress)
goto out;
}

btrfs_release_path(path);
key.offset = found_key.offset + 1;
path->slots[0]++;
}

ret = 1;
Expand Down Expand Up @@ -3620,15 +3632,22 @@ static int process_all_refs(struct send_ctx *sctx,
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_INODE_REF_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret)
break;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;

while (1) {
eb = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
continue;
}

btrfs_item_key_to_cpu(eb, &found_key, slot);

if (found_key.objectid != key.objectid ||
Expand All @@ -3637,11 +3656,10 @@ static int process_all_refs(struct send_ctx *sctx,
break;

ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx);
btrfs_release_path(path);
if (ret < 0)
goto out;

key.offset = found_key.offset + 1;
path->slots[0]++;
}
btrfs_release_path(path);

Expand Down Expand Up @@ -3922,19 +3940,25 @@ static int process_all_new_xattrs(struct send_ctx *sctx)
key.objectid = sctx->cmp_key->objectid;
key.type = BTRFS_XATTR_ITEM_KEY;
key.offset = 0;
while (1) {
ret = btrfs_search_slot_for_read(root, &key, path, 1, 0);
if (ret < 0)
goto out;
if (ret) {
ret = 0;
goto out;
}
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;

while (1) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &found_key, slot);
if (slot >= btrfs_header_nritems(eb)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0) {
goto out;
} else if (ret > 0) {
ret = 0;
break;
}
continue;
}

btrfs_item_key_to_cpu(eb, &found_key, slot);
if (found_key.objectid != key.objectid ||
found_key.type != key.type) {
ret = 0;
Expand All @@ -3946,8 +3970,7 @@ static int process_all_new_xattrs(struct send_ctx *sctx)
if (ret < 0)
goto out;

btrfs_release_path(path);
key.offset = found_key.offset + 1;
path->slots[0]++;
}

out:
Expand Down

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