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yaml
---
r: 128864
b: refs/heads/master
c: f321e49
h: refs/heads/master
v: v3
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Yan Zheng authored and Chris Mason committed Sep 25, 2008
1 parent 5551b29 commit 3e9fa10
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Showing 6 changed files with 143 additions and 97 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 3bf10418675cb424724b5cb9d7725b234defe1fd
refs/heads/master: f321e4910398cf7922265d269fb17fd26f312571
9 changes: 4 additions & 5 deletions trunk/fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -617,7 +617,7 @@ struct btrfs_leaf_ref_tree {
* in ram representation of the tree. extent_root is used for all allocations
* and for the extent tree extent_root root.
*/
struct dirty_root;
struct btrfs_dirty_root;
struct btrfs_root {
struct extent_buffer *node;

Expand All @@ -627,7 +627,7 @@ struct btrfs_root {
struct extent_buffer *commit_root;
struct btrfs_leaf_ref_tree *ref_tree;
struct btrfs_leaf_ref_tree ref_tree_struct;
struct dirty_root *dirty_root;
struct btrfs_dirty_root *dirty_root;

struct btrfs_root_item root_item;
struct btrfs_key root_key;
Expand Down Expand Up @@ -1399,9 +1399,8 @@ static inline struct dentry *fdentry(struct file *file) {
}

/* extent-tree.c */
u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
struct btrfs_path *count_path,
u64 expected_owner, u64 first_extent);
int btrfs_cross_ref_exists(struct btrfs_root *root,
struct btrfs_key *key, u64 bytenr);
int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy);
Expand Down
202 changes: 126 additions & 76 deletions trunk/fs/btrfs/extent-tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -802,70 +802,57 @@ static int lookup_extent_ref(struct btrfs_trans_handle *trans,
return 0;
}

u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
struct btrfs_path *count_path,
u64 expected_owner,
u64 first_extent)

static int get_reference_status(struct btrfs_root *root, u64 bytenr,
u64 parent_gen, u64 ref_objectid,
u64 *min_generation, u32 *ref_count)
{
struct btrfs_root *extent_root = root->fs_info->extent_root;
struct btrfs_path *path;
u64 bytenr;
u64 found_objectid;
u64 found_owner;
struct extent_buffer *leaf;
struct btrfs_extent_ref *ref_item;
struct btrfs_key key;
struct btrfs_key found_key;
u64 root_objectid = root->root_key.objectid;
u32 total_count = 0;
u32 extent_refs;
u32 cur_count;
u64 ref_generation;
u32 nritems;
int ret;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *l;
struct btrfs_extent_item *item;
struct btrfs_extent_ref *ref_item;
int level = -1;

/* FIXME, needs locking */
BUG();

mutex_lock(&root->fs_info->alloc_mutex);
path = btrfs_alloc_path();
again:
if (level == -1)
bytenr = first_extent;
else
bytenr = count_path->nodes[level]->start;

cur_count = 0;
key.objectid = bytenr;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;

btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
path = btrfs_alloc_path();
mutex_lock(&root->fs_info->alloc_mutex);
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0);

l = path->nodes[0];
btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

if (found_key.objectid != bytenr ||
found_key.type != BTRFS_EXTENT_ITEM_KEY) {
ret = 1;
goto out;
}

item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
extent_refs = btrfs_extent_refs(l, item);
*ref_count = 0;
*min_generation = (u64)-1;

while (1) {
l = path->nodes[0];
nritems = btrfs_header_nritems(l);
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(extent_root, path);
if (ret < 0)
goto out;
if (ret == 0)
continue;
break;
}
btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.objectid != bytenr)
break;

Expand All @@ -874,57 +861,120 @@ u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
continue;
}

cur_count++;
ref_item = btrfs_item_ptr(l, path->slots[0],
ref_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_ref);
found_objectid = btrfs_ref_root(l, ref_item);

if (found_objectid != root_objectid) {
total_count = 2;
goto out;
}
if (level == -1) {
found_owner = btrfs_ref_objectid(l, ref_item);
if (found_owner != expected_owner) {
total_count = 2;
goto out;
}
/*
* nasty. we don't count a reference held by
* the running transaction. This allows nodatacow
* to avoid cow most of the time
*/
if (found_owner >= BTRFS_FIRST_FREE_OBJECTID &&
btrfs_ref_generation(l, ref_item) ==
root->fs_info->generation) {
extent_refs--;
}
ref_generation = btrfs_ref_generation(leaf, ref_item);
/*
* For (parent_gen > 0 && parent_gen > ref_gen):
*
* we reach here through the oldest root, therefore
* all other reference from same snapshot should have
* a larger generation.
*/
if ((root_objectid != btrfs_ref_root(leaf, ref_item)) ||
(parent_gen > 0 && parent_gen > ref_generation) ||
(ref_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
ref_objectid != btrfs_ref_objectid(leaf, ref_item))) {
if (ref_count)
*ref_count = 2;
break;
}
total_count = 1;

*ref_count = 1;
if (*min_generation > ref_generation)
*min_generation = ref_generation;

path->slots[0]++;
}
/*
* if there is more than one reference against a data extent,
* we have to assume the other ref is another snapshot
*/
if (level == -1 && extent_refs > 1) {
total_count = 2;
ret = 0;
out:
mutex_unlock(&root->fs_info->alloc_mutex);
btrfs_free_path(path);
return ret;
}

int btrfs_cross_ref_exists(struct btrfs_root *root,
struct btrfs_key *key, u64 bytenr)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *old_root;
struct btrfs_path *path = NULL;
struct extent_buffer *eb;
struct btrfs_file_extent_item *item;
u64 ref_generation;
u64 min_generation;
u64 extent_start;
u32 ref_count;
int level;
int ret;

BUG_ON(key->type != BTRFS_EXTENT_DATA_KEY);
ret = get_reference_status(root, bytenr, 0, key->objectid,
&min_generation, &ref_count);
if (ret)
return ret;

if (ref_count != 1)
return 1;

trans = btrfs_start_transaction(root, 0);
old_root = root->dirty_root->root;
ref_generation = old_root->root_key.offset;

/* all references are created in running transaction */
if (min_generation > ref_generation) {
ret = 0;
goto out;
}
if (cur_count == 0) {
total_count = 0;

path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
if (level >= 0 && root->node == count_path->nodes[level])

path->skip_locking = 1;
/* if no item found, the extent is referenced by other snapshot */
ret = btrfs_search_slot(NULL, old_root, key, path, 0, 0);
if (ret)
goto out;
level++;
btrfs_release_path(root, path);
goto again;

eb = path->nodes[0];
item = btrfs_item_ptr(eb, path->slots[0],
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(eb, item) != BTRFS_FILE_EXTENT_REG ||
btrfs_file_extent_disk_bytenr(eb, item) != bytenr) {
ret = 1;
goto out;
}

for (level = BTRFS_MAX_LEVEL - 1; level >= -1; level--) {
if (level >= 0) {
eb = path->nodes[level];
if (!eb)
continue;
extent_start = eb->start;
} else
extent_start = bytenr;

ret = get_reference_status(root, extent_start, ref_generation,
0, &min_generation, &ref_count);
if (ret)
goto out;

if (ref_count != 1) {
ret = 1;
goto out;
}
if (level >= 0)
ref_generation = btrfs_header_generation(eb);
}
ret = 0;
out:
btrfs_free_path(path);
mutex_unlock(&root->fs_info->alloc_mutex);
return total_count;
if (path)
btrfs_free_path(path);
btrfs_end_transaction(trans, root);
return ret;
}

int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
Expand Down
6 changes: 2 additions & 4 deletions trunk/fs/btrfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -249,11 +249,8 @@ static int run_delalloc_nocow(struct inode *inode, u64 start, u64 end)
if (bytenr == 0)
goto not_found;

if (btrfs_count_snapshots_in_path(root, path, inode->i_ino,
bytenr) != 1) {
if (btrfs_cross_ref_exists(root, &found_key, bytenr))
goto not_found;
}

/*
* we may be called by the resizer, make sure we're inside
* the limits of the FS
Expand All @@ -277,6 +274,7 @@ static int run_delalloc_nocow(struct inode *inode, u64 start, u64 end)
goto again;

not_found:
btrfs_release_path(root, path);
cow_file_range(inode, start, end);
start = end + 1;
goto loop;
Expand Down
16 changes: 5 additions & 11 deletions trunk/fs/btrfs/transaction.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,12 +32,6 @@ extern struct kmem_cache *btrfs_transaction_cachep;

#define BTRFS_ROOT_TRANS_TAG 0

struct dirty_root {
struct list_head list;
struct btrfs_root *root;
struct btrfs_root *latest_root;
};

static noinline void put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(transaction->use_count == 0);
Expand Down Expand Up @@ -91,7 +85,7 @@ static noinline int join_transaction(struct btrfs_root *root)

static noinline int record_root_in_trans(struct btrfs_root *root)
{
struct dirty_root *dirty;
struct btrfs_dirty_root *dirty;
u64 running_trans_id = root->fs_info->running_transaction->transid;
if (root->ref_cows && root->last_trans < running_trans_id) {
WARN_ON(root == root->fs_info->extent_root);
Expand Down Expand Up @@ -372,7 +366,7 @@ int btrfs_add_dead_root(struct btrfs_root *root,
struct btrfs_root *latest,
struct list_head *dead_list)
{
struct dirty_root *dirty;
struct btrfs_dirty_root *dirty;

dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
if (!dirty)
Expand All @@ -387,7 +381,7 @@ static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
struct radix_tree_root *radix,
struct list_head *list)
{
struct dirty_root *dirty;
struct btrfs_dirty_root *dirty;
struct btrfs_root *gang[8];
struct btrfs_root *root;
int i;
Expand Down Expand Up @@ -498,7 +492,7 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
struct list_head *list)
{
struct dirty_root *dirty;
struct btrfs_dirty_root *dirty;
struct btrfs_trans_handle *trans;
unsigned long nr;
u64 num_bytes;
Expand All @@ -509,7 +503,7 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
while(!list_empty(list)) {
struct btrfs_root *root;

dirty = list_entry(list->prev, struct dirty_root, list);
dirty = list_entry(list->prev, struct btrfs_dirty_root, list);
list_del_init(&dirty->list);

num_bytes = btrfs_root_used(&dirty->root->root_item);
Expand Down
5 changes: 5 additions & 0 deletions trunk/fs/btrfs/transaction.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,11 @@ struct btrfs_pending_snapshot {
struct list_head list;
};

struct btrfs_dirty_root {
struct list_head list;
struct btrfs_root *root;
struct btrfs_root *latest_root;
};

static inline void btrfs_set_trans_block_group(struct btrfs_trans_handle *trans,
struct inode *inode)
Expand Down

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