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Btrfs: do not reuse objectid of deleted snapshot/subvol

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The new back reference format does not allow reusing objectid of
deleted snapshot/subvol. So we use ++highest_objectid to allocate
objectid for new snapshot/subvol.

Now we use ++highest_objectid to allocate objectid for both new inode
and new snapshot/subvolume, so this patch removes 'find hole' code in
btrfs_find_free_objectid.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Yan, Zheng 2009-09-21 15:56:00 -04:00 • committed by Chris Mason
parent 1c4850e21d
commit 13a8a7c8c4
6 changed files with 31 additions and 116 deletions
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93
fs/btrfs/inode-map.c
View file

@ -43,9 +43,10 @@ int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
slot = path->slots[0] - 1;
l = path->nodes[0];
btrfs_item_key_to_cpu(l, &found_key, slot);
*objectid = found_key.objectid;
*objectid = max_t(u64, found_key.objectid,
BTRFS_FIRST_FREE_OBJECTID - 1);
} else {
*objectid = BTRFS_FIRST_FREE_OBJECTID;
*objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
}
ret = 0;
error:
@ -53,91 +54,27 @@ error:
return ret;
}
/*
* walks the btree of allocated inodes and find a hole.
*/
int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 dirid, u64 *objectid)
{
struct btrfs_path *path;
struct btrfs_key key;
int ret;
int slot = 0;
u64 last_ino = 0;
int start_found;
struct extent_buffer *l;
struct btrfs_key search_key;
u64 search_start = dirid;
mutex_lock(&root->objectid_mutex);
if (root->last_inode_alloc >= BTRFS_FIRST_FREE_OBJECTID &&
root->last_inode_alloc < BTRFS_LAST_FREE_OBJECTID) {
*objectid = ++root->last_inode_alloc;
mutex_unlock(&root->objectid_mutex);
return 0;
if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
ret = btrfs_find_highest_inode(root, &root->highest_objectid);
if (ret)
goto out;
}
path = btrfs_alloc_path();
BUG_ON(!path);
search_start = max(search_start, (u64)BTRFS_FIRST_FREE_OBJECTID);
search_key.objectid = search_start;
search_key.type = 0;
search_key.offset = 0;
start_found = 0;
ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
if (ret < 0)
goto error;
while (1) {
l = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(l)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto error;
if (!start_found) {
*objectid = search_start;
start_found = 1;
goto found;
}
*objectid = last_ino > search_start ?
last_ino : search_start;
goto found;
}
btrfs_item_key_to_cpu(l, &key, slot);
if (key.objectid >= search_start) {
if (start_found) {
if (last_ino < search_start)
last_ino = search_start;
if (key.objectid > last_ino) {
*objectid = last_ino;
goto found;
}
} else if (key.objectid > search_start) {
*objectid = search_start;
goto found;
}
}
if (key.objectid >= BTRFS_LAST_FREE_OBJECTID)
break;
start_found = 1;
last_ino = key.objectid + 1;
path->slots[0]++;
if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
ret = -ENOSPC;
goto out;
}
BUG_ON(1);
found:
btrfs_release_path(root, path);
btrfs_free_path(path);
BUG_ON(*objectid < search_start);
mutex_unlock(&root->objectid_mutex);
return 0;
error:
btrfs_release_path(root, path);
btrfs_free_path(path);
*objectid = ++root->highest_objectid;
ret = 0;
out:
mutex_unlock(&root->objectid_mutex);
return ret;
}