2007-06-12 13:07:21 +00:00
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
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#include <linux/delay.h>
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#include <linux/kthread.h>
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#include <linux/pagemap.h>
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2007-03-20 18:38:32 +00:00
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#include "ctree.h"
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#include "disk-io.h"
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
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#include "free-space-cache.h"
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#include "inode-map.h"
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2007-03-20 18:38:32 +00:00
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#include "transaction.h"
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|
|
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
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static int caching_kthread(void *data)
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{
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struct btrfs_root *root = data;
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
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struct btrfs_key key;
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struct btrfs_path *path;
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struct extent_buffer *leaf;
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u64 last = (u64)-1;
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int slot;
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int ret;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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/* Since the commit root is read-only, we can safely skip locking. */
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path->skip_locking = 1;
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path->search_commit_root = 1;
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path->reada = 2;
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key.objectid = BTRFS_FIRST_FREE_OBJECTID;
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key.offset = 0;
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key.type = BTRFS_INODE_ITEM_KEY;
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again:
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/* need to make sure the commit_root doesn't disappear */
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mutex_lock(&root->fs_commit_mutex);
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ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
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if (ret < 0)
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goto out;
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while (1) {
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smp_mb();
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if (fs_info->closing > 1)
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goto out;
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leaf = path->nodes[0];
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slot = path->slots[0];
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if (path->slots[0] >= btrfs_header_nritems(leaf)) {
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ret = btrfs_next_leaf(root, path);
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if (ret < 0)
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goto out;
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else if (ret > 0)
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break;
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if (need_resched() ||
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btrfs_transaction_in_commit(fs_info)) {
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leaf = path->nodes[0];
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if (btrfs_header_nritems(leaf) == 0) {
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WARN_ON(1);
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break;
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}
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/*
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* Save the key so we can advances forward
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* in the next search.
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*/
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btrfs_item_key_to_cpu(leaf, &key, 0);
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2011-05-22 16:33:42 +00:00
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btrfs_release_path(path);
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
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root->cache_progress = last;
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mutex_unlock(&root->fs_commit_mutex);
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schedule_timeout(1);
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goto again;
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} else
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continue;
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}
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btrfs_item_key_to_cpu(leaf, &key, slot);
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if (key.type != BTRFS_INODE_ITEM_KEY)
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goto next;
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if (key.objectid >= BTRFS_LAST_FREE_OBJECTID)
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break;
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if (last != (u64)-1 && last + 1 != key.objectid) {
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__btrfs_add_free_space(ctl, last + 1,
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key.objectid - last - 1);
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wake_up(&root->cache_wait);
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}
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last = key.objectid;
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next:
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path->slots[0]++;
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}
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if (last < BTRFS_LAST_FREE_OBJECTID - 1) {
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__btrfs_add_free_space(ctl, last + 1,
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BTRFS_LAST_FREE_OBJECTID - last - 1);
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}
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spin_lock(&root->cache_lock);
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root->cached = BTRFS_CACHE_FINISHED;
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spin_unlock(&root->cache_lock);
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root->cache_progress = (u64)-1;
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btrfs_unpin_free_ino(root);
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out:
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wake_up(&root->cache_wait);
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mutex_unlock(&root->fs_commit_mutex);
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btrfs_free_path(path);
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return ret;
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}
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static void start_caching(struct btrfs_root *root)
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{
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struct task_struct *tsk;
|
2011-04-20 02:33:24 +00:00
|
|
|
int ret;
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
|
|
|
|
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|
spin_lock(&root->cache_lock);
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|
|
if (root->cached != BTRFS_CACHE_NO) {
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|
|
spin_unlock(&root->cache_lock);
|
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|
|
return;
|
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|
|
}
|
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|
|
|
|
|
|
root->cached = BTRFS_CACHE_STARTED;
|
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|
|
spin_unlock(&root->cache_lock);
|
|
|
|
|
2011-04-20 02:33:24 +00:00
|
|
|
ret = load_free_ino_cache(root->fs_info, root);
|
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|
|
if (ret == 1) {
|
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|
|
spin_lock(&root->cache_lock);
|
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|
|
root->cached = BTRFS_CACHE_FINISHED;
|
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|
|
spin_unlock(&root->cache_lock);
|
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|
|
return;
|
|
|
|
}
|
|
|
|
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
|
|
|
tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu\n",
|
|
|
|
root->root_key.objectid);
|
|
|
|
BUG_ON(IS_ERR(tsk));
|
|
|
|
}
|
|
|
|
|
|
|
|
int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
|
|
|
|
{
|
|
|
|
again:
|
|
|
|
*objectid = btrfs_find_ino_for_alloc(root);
|
|
|
|
|
|
|
|
if (*objectid != 0)
|
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|
|
return 0;
|
|
|
|
|
|
|
|
start_caching(root);
|
|
|
|
|
|
|
|
wait_event(root->cache_wait,
|
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|
|
root->cached == BTRFS_CACHE_FINISHED ||
|
|
|
|
root->free_ino_ctl->free_space > 0);
|
|
|
|
|
|
|
|
if (root->cached == BTRFS_CACHE_FINISHED &&
|
|
|
|
root->free_ino_ctl->free_space == 0)
|
|
|
|
return -ENOSPC;
|
|
|
|
else
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
|
|
|
|
void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
|
|
|
|
{
|
|
|
|
struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
|
|
|
|
struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
|
|
|
|
again:
|
|
|
|
if (root->cached == BTRFS_CACHE_FINISHED) {
|
|
|
|
__btrfs_add_free_space(ctl, objectid, 1);
|
|
|
|
} else {
|
|
|
|
/*
|
|
|
|
* If we are in the process of caching free ino chunks,
|
|
|
|
* to avoid adding the same inode number to the free_ino
|
|
|
|
* tree twice due to cross transaction, we'll leave it
|
|
|
|
* in the pinned tree until a transaction is committed
|
|
|
|
* or the caching work is done.
|
|
|
|
*/
|
|
|
|
|
|
|
|
mutex_lock(&root->fs_commit_mutex);
|
|
|
|
spin_lock(&root->cache_lock);
|
|
|
|
if (root->cached == BTRFS_CACHE_FINISHED) {
|
|
|
|
spin_unlock(&root->cache_lock);
|
|
|
|
mutex_unlock(&root->fs_commit_mutex);
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
spin_unlock(&root->cache_lock);
|
|
|
|
|
|
|
|
start_caching(root);
|
|
|
|
|
|
|
|
if (objectid <= root->cache_progress)
|
|
|
|
__btrfs_add_free_space(ctl, objectid, 1);
|
|
|
|
else
|
|
|
|
__btrfs_add_free_space(pinned, objectid, 1);
|
|
|
|
|
|
|
|
mutex_unlock(&root->fs_commit_mutex);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* When a transaction is committed, we'll move those inode numbers which
|
|
|
|
* are smaller than root->cache_progress from pinned tree to free_ino tree,
|
|
|
|
* and others will just be dropped, because the commit root we were
|
|
|
|
* searching has changed.
|
|
|
|
*
|
|
|
|
* Must be called with root->fs_commit_mutex held
|
|
|
|
*/
|
|
|
|
void btrfs_unpin_free_ino(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
|
|
|
|
struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
|
|
|
|
struct btrfs_free_space *info;
|
|
|
|
struct rb_node *n;
|
|
|
|
u64 count;
|
|
|
|
|
|
|
|
while (1) {
|
|
|
|
n = rb_first(rbroot);
|
|
|
|
if (!n)
|
|
|
|
break;
|
|
|
|
|
|
|
|
info = rb_entry(n, struct btrfs_free_space, offset_index);
|
|
|
|
BUG_ON(info->bitmap);
|
|
|
|
|
|
|
|
if (info->offset > root->cache_progress)
|
|
|
|
goto free;
|
|
|
|
else if (info->offset + info->bytes > root->cache_progress)
|
|
|
|
count = root->cache_progress - info->offset + 1;
|
|
|
|
else
|
|
|
|
count = info->bytes;
|
|
|
|
|
|
|
|
__btrfs_add_free_space(ctl, info->offset, count);
|
|
|
|
free:
|
|
|
|
rb_erase(&info->offset_index, rbroot);
|
|
|
|
kfree(info);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
#define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space))
|
|
|
|
#define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8)
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The goal is to keep the memory used by the free_ino tree won't
|
|
|
|
* exceed the memory if we use bitmaps only.
|
|
|
|
*/
|
|
|
|
static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
|
|
|
|
{
|
|
|
|
struct btrfs_free_space *info;
|
|
|
|
struct rb_node *n;
|
|
|
|
int max_ino;
|
|
|
|
int max_bitmaps;
|
|
|
|
|
|
|
|
n = rb_last(&ctl->free_space_offset);
|
|
|
|
if (!n) {
|
|
|
|
ctl->extents_thresh = INIT_THRESHOLD;
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
info = rb_entry(n, struct btrfs_free_space, offset_index);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Find the maximum inode number in the filesystem. Note we
|
|
|
|
* ignore the fact that this can be a bitmap, because we are
|
|
|
|
* not doing precise calculation.
|
|
|
|
*/
|
|
|
|
max_ino = info->bytes - 1;
|
|
|
|
|
|
|
|
max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
|
|
|
|
if (max_bitmaps <= ctl->total_bitmaps) {
|
|
|
|
ctl->extents_thresh = 0;
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
|
|
|
|
PAGE_CACHE_SIZE / sizeof(*info);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We don't fall back to bitmap, if we are below the extents threshold
|
|
|
|
* or this chunk of inode numbers is a big one.
|
|
|
|
*/
|
|
|
|
static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
|
|
|
|
struct btrfs_free_space *info)
|
|
|
|
{
|
|
|
|
if (ctl->free_extents < ctl->extents_thresh ||
|
|
|
|
info->bytes > INODES_PER_BITMAP / 10)
|
|
|
|
return false;
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct btrfs_free_space_op free_ino_op = {
|
|
|
|
.recalc_thresholds = recalculate_thresholds,
|
|
|
|
.use_bitmap = use_bitmap,
|
|
|
|
};
|
|
|
|
|
|
|
|
static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
|
|
|
|
struct btrfs_free_space *info)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* We always use extents for two reasons:
|
|
|
|
*
|
|
|
|
* - The pinned tree is only used during the process of caching
|
|
|
|
* work.
|
|
|
|
* - Make code simpler. See btrfs_unpin_free_ino().
|
|
|
|
*/
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct btrfs_free_space_op pinned_free_ino_op = {
|
|
|
|
.recalc_thresholds = pinned_recalc_thresholds,
|
|
|
|
.use_bitmap = pinned_use_bitmap,
|
|
|
|
};
|
|
|
|
|
|
|
|
void btrfs_init_free_ino_ctl(struct btrfs_root *root)
|
|
|
|
{
|
|
|
|
struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
|
|
|
|
struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
|
|
|
|
|
|
|
|
spin_lock_init(&ctl->tree_lock);
|
|
|
|
ctl->unit = 1;
|
|
|
|
ctl->start = 0;
|
|
|
|
ctl->private = NULL;
|
|
|
|
ctl->op = &free_ino_op;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Initially we allow to use 16K of ram to cache chunks of
|
|
|
|
* inode numbers before we resort to bitmaps. This is somewhat
|
|
|
|
* arbitrary, but it will be adjusted in runtime.
|
|
|
|
*/
|
|
|
|
ctl->extents_thresh = INIT_THRESHOLD;
|
|
|
|
|
|
|
|
spin_lock_init(&pinned->tree_lock);
|
|
|
|
pinned->unit = 1;
|
|
|
|
pinned->start = 0;
|
|
|
|
pinned->private = NULL;
|
|
|
|
pinned->extents_thresh = 0;
|
|
|
|
pinned->op = &pinned_free_ino_op;
|
|
|
|
}
|
|
|
|
|
2011-04-20 02:33:24 +00:00
|
|
|
int btrfs_save_ino_cache(struct btrfs_root *root,
|
|
|
|
struct btrfs_trans_handle *trans)
|
|
|
|
{
|
|
|
|
struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
|
|
|
|
struct btrfs_path *path;
|
|
|
|
struct inode *inode;
|
|
|
|
u64 alloc_hint = 0;
|
|
|
|
int ret;
|
|
|
|
int prealloc;
|
|
|
|
bool retry = false;
|
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
|
|
|
again:
|
|
|
|
inode = lookup_free_ino_inode(root, path);
|
|
|
|
if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
|
|
|
|
ret = PTR_ERR(inode);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (IS_ERR(inode)) {
|
|
|
|
BUG_ON(retry);
|
|
|
|
retry = true;
|
|
|
|
|
|
|
|
ret = create_free_ino_inode(root, trans, path);
|
|
|
|
if (ret)
|
|
|
|
goto out;
|
|
|
|
goto again;
|
|
|
|
}
|
|
|
|
|
|
|
|
BTRFS_I(inode)->generation = 0;
|
|
|
|
ret = btrfs_update_inode(trans, root, inode);
|
|
|
|
WARN_ON(ret);
|
|
|
|
|
|
|
|
if (i_size_read(inode) > 0) {
|
|
|
|
ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
|
|
|
|
if (ret)
|
|
|
|
goto out_put;
|
|
|
|
}
|
|
|
|
|
|
|
|
spin_lock(&root->cache_lock);
|
|
|
|
if (root->cached != BTRFS_CACHE_FINISHED) {
|
|
|
|
ret = -1;
|
|
|
|
spin_unlock(&root->cache_lock);
|
|
|
|
goto out_put;
|
|
|
|
}
|
|
|
|
spin_unlock(&root->cache_lock);
|
|
|
|
|
|
|
|
spin_lock(&ctl->tree_lock);
|
|
|
|
prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
|
|
|
|
prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE);
|
|
|
|
prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE;
|
|
|
|
spin_unlock(&ctl->tree_lock);
|
|
|
|
|
|
|
|
/* Just to make sure we have enough space */
|
|
|
|
prealloc += 8 * PAGE_CACHE_SIZE;
|
|
|
|
|
|
|
|
ret = btrfs_check_data_free_space(inode, prealloc);
|
|
|
|
if (ret)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
|
|
|
|
prealloc, prealloc, &alloc_hint);
|
|
|
|
if (ret)
|
|
|
|
goto out_put;
|
|
|
|
btrfs_free_reserved_data_space(inode, prealloc);
|
|
|
|
|
|
|
|
out_put:
|
|
|
|
iput(inode);
|
|
|
|
out:
|
|
|
|
if (ret == 0)
|
|
|
|
ret = btrfs_write_out_ino_cache(root, trans, path);
|
|
|
|
|
|
|
|
btrfs_free_path(path);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
|
|
|
static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
|
2007-04-05 17:35:25 +00:00
|
|
|
{
|
|
|
|
struct btrfs_path *path;
|
|
|
|
int ret;
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *l;
|
2007-04-05 17:35:25 +00:00
|
|
|
struct btrfs_key search_key;
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_key found_key;
|
2007-04-05 17:35:25 +00:00
|
|
|
int slot;
|
|
|
|
|
|
|
|
path = btrfs_alloc_path();
|
2011-03-23 08:14:16 +00:00
|
|
|
if (!path)
|
|
|
|
return -ENOMEM;
|
2007-04-05 17:35:25 +00:00
|
|
|
|
2008-09-05 20:43:53 +00:00
|
|
|
search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
|
|
|
|
search_key.type = -1;
|
2007-04-05 17:35:25 +00:00
|
|
|
search_key.offset = (u64)-1;
|
|
|
|
ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
|
|
|
|
if (ret < 0)
|
|
|
|
goto error;
|
|
|
|
BUG_ON(ret == 0);
|
|
|
|
if (path->slots[0] > 0) {
|
|
|
|
slot = path->slots[0] - 1;
|
2007-10-15 20:14:19 +00:00
|
|
|
l = path->nodes[0];
|
|
|
|
btrfs_item_key_to_cpu(l, &found_key, slot);
|
2009-09-21 19:56:00 +00:00
|
|
|
*objectid = max_t(u64, found_key.objectid,
|
|
|
|
BTRFS_FIRST_FREE_OBJECTID - 1);
|
2007-04-05 17:35:25 +00:00
|
|
|
} else {
|
2009-09-21 19:56:00 +00:00
|
|
|
*objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
|
2007-04-05 17:35:25 +00:00
|
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
error:
|
|
|
|
btrfs_free_path(path);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
|
|
|
int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
|
2007-03-20 18:38:32 +00:00
|
|
|
{
|
|
|
|
int ret;
|
2008-06-25 20:01:30 +00:00
|
|
|
mutex_lock(&root->objectid_mutex);
|
2007-03-20 18:38:32 +00:00
|
|
|
|
2009-09-21 19:56:00 +00:00
|
|
|
if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
|
Btrfs: Cache free inode numbers in memory
Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.
This fixes it, and it works similarly to how we cache free space in block
cgroups.
We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.
Because we are searching the commit root, we have to carefully handle the
cross-transaction case.
The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-20 02:06:11 +00:00
|
|
|
ret = btrfs_find_highest_objectid(root,
|
|
|
|
&root->highest_objectid);
|
2009-09-21 19:56:00 +00:00
|
|
|
if (ret)
|
|
|
|
goto out;
|
|
|
|
}
|
2008-09-26 14:05:38 +00:00
|
|
|
|
2009-09-21 19:56:00 +00:00
|
|
|
if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
|
|
|
|
ret = -ENOSPC;
|
|
|
|
goto out;
|
2007-03-20 18:38:32 +00:00
|
|
|
}
|
2009-09-21 19:56:00 +00:00
|
|
|
|
|
|
|
*objectid = ++root->highest_objectid;
|
|
|
|
ret = 0;
|
|
|
|
out:
|
2008-06-25 20:01:30 +00:00
|
|
|
mutex_unlock(&root->objectid_mutex);
|
2007-03-20 18:38:32 +00:00
|
|
|
return ret;
|
|
|
|
}
|