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author | Qu Wenruo <wqu@suse.com> | 2020-02-13 14:11:04 +0800 |
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committer | David Sterba <dsterba@suse.com> | 2020-05-25 11:25:16 +0200 |
commit | a37f232b7b65789cadc9834d389f6390de11b583 (patch) | |
tree | 4b36e9c656727c9a4f6511074400e85632047ff6 /lib/kfifo.c | |
parent | 78d933c79cb649906577715af15400c7724ca633 (diff) |
btrfs: backref: introduce the skeleton of btrfs_backref_iter
Due to the complex nature of btrfs extent tree, when we want to iterate
all backrefs of one extent, this involves quite a lot of work, like
searching the EXTENT_ITEM/METADATA_ITEM, iteration through inline and keyed
backrefs.
Normally this would result in a complex code, something like:
btrfs_search_slot()
/* Ensure we are at EXTENT_ITEM/METADATA_ITEM */
while (1) { /* Loop for extent tree items */
while (ptr < end) { /* Loop for inlined items */
/* Real work here */
}
next:
ret = btrfs_next_item()
/* Ensure we're still at keyed item for specified bytenr */
}
The idea of btrfs_backref_iter is to avoid such complex and hard to
read code structure, but something like the following:
iter = btrfs_backref_iter_alloc();
ret = btrfs_backref_iter_start(iter, bytenr);
if (ret < 0)
goto out;
for (; ; ret = btrfs_backref_iter_next(iter)) {
/* Real work here */
}
out:
btrfs_backref_iter_free(iter);
This patch is just the skeleton + btrfs_backref_iter_start() code.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'lib/kfifo.c')
0 files changed, 0 insertions, 0 deletions