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btrfs-progs: extent-tree: Introduce function to check if there is any extent in given range.

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Introduce a new function, btrfs_check_extent_exists(), to check if there
is any extent in the range specified by user.

The parameter can be a large range, and if any extent exists in the
range, it will return >0 (in fact it will return 1).
Or return 0 if no extent is found.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Gu Jinxiang <gujx@cn.fujitsu.com>
This commit is contained in:
Qu Wenruo 2016-12-26 14:29:35 +08:00 committed by David Sterba
parent 116b4d33ce
commit e2c28e53dd
2 changed files with 62 additions and 0 deletions
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2
ctree.h
View File

@ -2524,6 +2524,8 @@ int exclude_super_stripes(struct btrfs_root *root,
u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
struct btrfs_fs_info *info, u64 start, u64 end);
u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset);
int btrfs_check_extent_exists(struct btrfs_fs_info *fs_info, u64 start,
u64 len);
/* ctree.c */
int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2);

60
extent-tree.c
View File

@ -4255,3 +4255,63 @@ u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
return total_added;
}
/*
* Check if there is any extent(both data and metadata) in the range
* [@start, @start + @len)
*
* Return 0 for no extent found.
* Return >0 for found extent.
* Return <0 for fatal error.
*/
int btrfs_check_extent_exists(struct btrfs_fs_info *fs_info, u64 start,
u64 len)
{
struct btrfs_path *path;
struct btrfs_key key;
u64 extent_start;
u64 extent_len;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = start + len;
key.type = 0;
key.offset = 0;
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
/*
* Now we're pointing at slot whose key.object >= end, skip to previous
* extent.
*/
ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
if (ret < 0)
goto out;
if (ret > 0) {
ret = 0;
goto out;
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
extent_start = key.objectid;
if (key.type == BTRFS_METADATA_ITEM_KEY)
extent_len = fs_info->nodesize;
else
extent_len = key.offset;
/*
* search_slot() and previous_extent_item() has ensured that our
* extent_start < start + len, we only need to care extent end.
*/
if (extent_start + extent_len <= start)
ret = 0;
else
ret = 1;
out:
btrfs_free_path(path);
return ret;
}