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Btrfs: Integrate metadata reservation with start_transaction

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Besides simplify the code, this change makes sure all metadata
reservation for normal metadata operations are released after
committing transaction.

Changes since V1:

Add code that check if unlink and rmdir will free space.

Add ENOSPC handling for clone ioctl.

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
2010-05-16 10:48:46 -04:00
committed by Chris Mason
parent f0486c68e4
commit a22285a6a3
15 changed files with 685 additions and 535 deletions
Download Patch File Download Diff File Expand all files Collapse all files

283
fs/btrfs/extent-tree.c
View File

@@ -615,6 +615,113 @@ int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
return ret;
}
/*
* helper function to lookup reference count and flags of extent.
*
* the head node for delayed ref is used to store the sum of all the
* reference count modifications queued up in the rbtree. the head
* node may also store the extent flags to set. This way you can check
* to see what the reference count and extent flags would be if all of
* the delayed refs are not processed.
*/
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 bytenr,
u64 num_bytes, u64 *refs, u64 *flags)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_path *path;
struct btrfs_extent_item *ei;
struct extent_buffer *leaf;
struct btrfs_key key;
u32 item_size;
u64 num_refs;
u64 extent_flags;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
if (!trans) {
path->skip_locking = 1;
path->search_commit_root = 1;
}
again:
ret = btrfs_search_slot(trans, root->fs_info->extent_root,
&key, path, 0, 0);
if (ret < 0)
goto out_free;
if (ret == 0) {
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (item_size >= sizeof(*ei)) {
ei = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
num_refs = btrfs_extent_refs(leaf, ei);
extent_flags = btrfs_extent_flags(leaf, ei);
} else {
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
struct btrfs_extent_item_v0 *ei0;
BUG_ON(item_size != sizeof(*ei0));
ei0 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item_v0);
num_refs = btrfs_extent_refs_v0(leaf, ei0);
/* FIXME: this isn't correct for data */
extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
#else
BUG();
#endif
}
BUG_ON(num_refs == 0);
} else {
num_refs = 0;
extent_flags = 0;
ret = 0;
}
if (!trans)
goto out;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(trans, bytenr);
if (head) {
if (!mutex_trylock(&head->mutex)) {
atomic_inc(&head->node.refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(root->fs_info->extent_root, path);
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref(&head->node);
goto again;
}
if (head->extent_op && head->extent_op->update_flags)
extent_flags |= head->extent_op->flags_to_set;
else
BUG_ON(num_refs == 0);
num_refs += head->node.ref_mod;
mutex_unlock(&head->mutex);
}
spin_unlock(&delayed_refs->lock);
out:
WARN_ON(num_refs == 0);
if (refs)
*refs = num_refs;
if (flags)
*flags = extent_flags;
out_free:
btrfs_free_path(path);
return ret;
}
/*
* Back reference rules. Back refs have three main goals:
*
@@ -2948,113 +3055,6 @@ again:
return 0;
}
/*
* unreserve num_items number of items worth of metadata space. This needs to
* be paired with btrfs_reserve_metadata_space.
*
* NOTE: if you have the option, run this _AFTER_ you do a
* btrfs_end_transaction, since btrfs_end_transaction will run delayed ref
* oprations which will result in more used metadata, so we want to make sure we
* can do that without issue.
*/
int btrfs_unreserve_metadata_space(struct btrfs_root *root, int num_items)
{
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_space_info *meta_sinfo;
u64 num_bytes;
u64 alloc_target;
bool bug = false;
/* get the space info for where the metadata will live */
alloc_target = btrfs_get_alloc_profile(root, 0);
meta_sinfo = __find_space_info(info, alloc_target);
num_bytes = calculate_bytes_needed(root, num_items);
spin_lock(&meta_sinfo->lock);
if (meta_sinfo->bytes_may_use < num_bytes) {
bug = true;
meta_sinfo->bytes_may_use = 0;
} else {
meta_sinfo->bytes_may_use -= num_bytes;
}
spin_unlock(&meta_sinfo->lock);
BUG_ON(bug);
return 0;
}
/*
* Reserve some metadata space for use. We'll calculate the worste case number
* of bytes that would be needed to modify num_items number of items. If we
* have space, fantastic, if not, you get -ENOSPC. Please call
* btrfs_unreserve_metadata_space when you are done for the _SAME_ number of
* items you reserved, since whatever metadata you needed should have already
* been allocated.
*
* This will commit the transaction to make more space if we don't have enough
* metadata space. THe only time we don't do this is if we're reserving space
* inside of a transaction, then we will just return -ENOSPC and it is the
* callers responsibility to handle it properly.
*/
int btrfs_reserve_metadata_space(struct btrfs_root *root, int num_items)
{
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_space_info *meta_sinfo;
u64 num_bytes;
u64 used;
u64 alloc_target;
int retries = 0;
/* get the space info for where the metadata will live */
alloc_target = btrfs_get_alloc_profile(root, 0);
meta_sinfo = __find_space_info(info, alloc_target);
num_bytes = calculate_bytes_needed(root, num_items);
again:
spin_lock(&meta_sinfo->lock);
if (unlikely(!meta_sinfo->bytes_root))
meta_sinfo->bytes_root = calculate_bytes_needed(root, 6);
if (!retries)
meta_sinfo->bytes_may_use += num_bytes;
used = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
meta_sinfo->bytes_super + meta_sinfo->bytes_root +
meta_sinfo->bytes_may_use + meta_sinfo->bytes_delalloc;
if (used > meta_sinfo->total_bytes) {
retries++;
if (retries == 1) {
if (maybe_allocate_chunk(NULL, root, meta_sinfo,
num_bytes))
goto again;
retries++;
} else {
spin_unlock(&meta_sinfo->lock);
}
if (retries == 2) {
shrink_delalloc(NULL, root, meta_sinfo, num_bytes);
goto again;
}
spin_lock(&meta_sinfo->lock);
meta_sinfo->bytes_may_use -= num_bytes;
spin_unlock(&meta_sinfo->lock);
dump_space_info(meta_sinfo, 0, 0);
return -ENOSPC;
}
check_force_delalloc(meta_sinfo);
spin_unlock(&meta_sinfo->lock);
return 0;
}
/*
* This will check the space that the inode allocates from to make sure we have
* enough space for bytes.
@@ -3095,9 +3095,9 @@ again:
spin_unlock(&data_sinfo->lock);
alloc:
alloc_target = btrfs_get_alloc_profile(root, 1);
trans = btrfs_start_transaction(root, 1);
if (!trans)
return -ENOMEM;
trans = btrfs_join_transaction(root, 1);
if (IS_ERR(trans))
return PTR_ERR(trans);
ret = do_chunk_alloc(trans, root->fs_info->extent_root,
bytes + 2 * 1024 * 1024,
@@ -3118,8 +3118,8 @@ alloc:
if (!committed && !root->fs_info->open_ioctl_trans) {
committed = 1;
trans = btrfs_join_transaction(root, 1);
if (!trans)
return -ENOMEM;
if (IS_ERR(trans))
return PTR_ERR(trans);
ret = btrfs_commit_transaction(trans, root);
if (ret)
return ret;
@@ -3701,6 +3701,59 @@ static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
}
static u64 calc_trans_metadata_size(struct btrfs_root *root, int num_items)
{
return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
3 * num_items;
}
int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
int num_items, int *retries)
{
u64 num_bytes;
int ret;
if (num_items == 0 || root->fs_info->chunk_root == root)
return 0;
num_bytes = calc_trans_metadata_size(root, num_items);
ret = btrfs_block_rsv_add(trans, root, &root->fs_info->trans_block_rsv,
num_bytes, retries);
if (!ret) {
trans->bytes_reserved += num_bytes;
trans->block_rsv = &root->fs_info->trans_block_rsv;
}
return ret;
}
void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
if (!trans->bytes_reserved)
return;
BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
btrfs_block_rsv_release(root, trans->block_rsv,
trans->bytes_reserved);
trans->bytes_reserved = 0;
}
int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
struct btrfs_pending_snapshot *pending)
{
struct btrfs_root *root = pending->root;
struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
/*
* two for root back/forward refs, two for directory entries
* and one for root of the snapshot.
*/
u64 num_bytes = calc_trans_metadata_size(root, 5);
dst_rsv->space_info = src_rsv->space_info;
return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
}
static int update_block_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 bytenr, u64 num_bytes, int alloc)
@@ -5824,7 +5877,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref)
wc = kzalloc(sizeof(*wc), GFP_NOFS);
BUG_ON(!wc);
trans = btrfs_start_transaction(tree_root, 1);
trans = btrfs_start_transaction(tree_root, 0);
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_header_level(root->node);
@@ -5920,7 +5973,9 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref)
BUG_ON(ret);
btrfs_end_transaction(trans, tree_root);
trans = btrfs_start_transaction(tree_root, 1);
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
} else {
unsigned long update;
update = trans->delayed_ref_updates;