| Message ID | 1375122154-5177-1-git-send-email-fdmanana@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On mon, 29 Jul 2013 19:22:34 +0100, Filipe David Borba Manana wrote: > After reading all device items from the chunk tree, don't > exit the loop and then navigate down the tree again to find > the chunk items. Instead just read all device items and > chunk items with a single tree search. This is possible > because all device items are found before any chunk item in > the chunks tree. > > Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> > --- > > V2: Simplified logic inside the loop > (suggested by Josef Bacik on irc). > > fs/btrfs/volumes.c | 30 ++++++++++-------------------- > 1 file changed, 10 insertions(+), 20 deletions(-) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 090f57c..45c5ec3 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -5676,14 +5676,13 @@ int btrfs_read_chunk_tree(struct btrfs_root *root) > mutex_lock(&uuid_mutex); > lock_chunks(root); > > - /* first we search for all of the device items, and then we > - * read in all of the chunk items. This way we can create chunk > - * mappings that reference all of the devices that are afound > - */ > + /* Read all device items, and then all the chunk items. All > + device items are found before any chunk item (their object id > + is smaller than the lowest possible object id for a chunk > + item - BTRFS_FIRST_CHUNK_TREE_OBJECTID). */ According to the coding style of the kernel(Documentation/CodingStyle), the preferred style for long (multi-line) comments is: /* * This is the preferred style for multi-line * comments in the Linux kernel source code. * * Description: A column of asterisks on the left side, * with beginning and ending almost-blank lines. */ The other code is OK. Reviewed-by: Miao Xie <miaox@cn.fujitsu.com> > key.objectid = BTRFS_DEV_ITEMS_OBJECTID; > key.offset = 0; > key.type = 0; > -again: > ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); > if (ret < 0) > goto error; > @@ -5699,17 +5698,13 @@ again: > break; > } > btrfs_item_key_to_cpu(leaf, &found_key, slot); > - if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) { > - if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID) > - break; > - if (found_key.type == BTRFS_DEV_ITEM_KEY) { > - struct btrfs_dev_item *dev_item; > - dev_item = btrfs_item_ptr(leaf, slot, > + if (found_key.type == BTRFS_DEV_ITEM_KEY) { > + struct btrfs_dev_item *dev_item; > + dev_item = btrfs_item_ptr(leaf, slot, > struct btrfs_dev_item); > - ret = read_one_dev(root, leaf, dev_item); > - if (ret) > - goto error; > - } > + ret = read_one_dev(root, leaf, dev_item); > + if (ret) > + goto error; > } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) { > struct btrfs_chunk *chunk; > chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk); > @@ -5719,11 +5714,6 @@ again: > } > path->slots[0]++; > } > - if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) { > - key.objectid = 0; > - btrfs_release_path(path); > - goto again; > - } > ret = 0; > error: > unlock_chunks(root); > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 090f57c..45c5ec3 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -5676,14 +5676,13 @@ int btrfs_read_chunk_tree(struct btrfs_root *root) mutex_lock(&uuid_mutex); lock_chunks(root); - /* first we search for all of the device items, and then we - * read in all of the chunk items. This way we can create chunk - * mappings that reference all of the devices that are afound - */ + /* Read all device items, and then all the chunk items. All + device items are found before any chunk item (their object id + is smaller than the lowest possible object id for a chunk + item - BTRFS_FIRST_CHUNK_TREE_OBJECTID). */ key.objectid = BTRFS_DEV_ITEMS_OBJECTID; key.offset = 0; key.type = 0; -again: ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto error; @@ -5699,17 +5698,13 @@ again: break; } btrfs_item_key_to_cpu(leaf, &found_key, slot); - if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) { - if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID) - break; - if (found_key.type == BTRFS_DEV_ITEM_KEY) { - struct btrfs_dev_item *dev_item; - dev_item = btrfs_item_ptr(leaf, slot, + if (found_key.type == BTRFS_DEV_ITEM_KEY) { + struct btrfs_dev_item *dev_item; + dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_dev_item); - ret = read_one_dev(root, leaf, dev_item); - if (ret) - goto error; - } + ret = read_one_dev(root, leaf, dev_item); + if (ret) + goto error; } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) { struct btrfs_chunk *chunk; chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk); @@ -5719,11 +5714,6 @@ again: } path->slots[0]++; } - if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) { - key.objectid = 0; - btrfs_release_path(path); - goto again; - } ret = 0; error: unlock_chunks(root);
After reading all device items from the chunk tree, don't exit the loop and then navigate down the tree again to find the chunk items. Instead just read all device items and chunk items with a single tree search. This is possible because all device items are found before any chunk item in the chunks tree. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> --- V2: Simplified logic inside the loop (suggested by Josef Bacik on irc). fs/btrfs/volumes.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-)