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ocfs2: Add support of decrementing refcount for delete.
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    Given a physical cpos and length, decrement the refcount
in the tree. If the refcount for any portion of the extent goes
to zero, that portion is queued for freeing.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
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Tao Ma authored and Joel Becker committed Sep 23, 2009
1 parent e73a819 commit 1823cb0
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Showing 4 changed files with 265 additions and 5 deletions.
6 changes: 3 additions & 3 deletions fs/ocfs2/alloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6522,9 +6522,9 @@ ocfs2_find_per_slot_free_list(int type,
return fl;
}

static int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
int type, int slot, u64 blkno,
unsigned int bit)
int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
int type, int slot, u64 blkno,
unsigned int bit)
{
int ret;
struct ocfs2_per_slot_free_list *fl;
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3 changes: 3 additions & 0 deletions fs/ocfs2/alloc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -202,6 +202,9 @@ static inline void ocfs2_init_dealloc_ctxt(struct ocfs2_cached_dealloc_ctxt *c)
}
int ocfs2_cache_cluster_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
u64 blkno, unsigned int bit);
int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
int type, int slot, u64 blkno,
unsigned int bit);
static inline int ocfs2_dealloc_has_cluster(struct ocfs2_cached_dealloc_ctxt *c)
{
return c->c_global_allocator != NULL;
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256 changes: 254 additions & 2 deletions fs/ocfs2/refcounttree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1071,6 +1071,10 @@ static void ocfs2_refcount_rec_merge(struct ocfs2_refcount_block *rb,
ocfs2_rotate_refcount_rec_left(rb, index);
}

/*
* Change the refcount indexed by "index" in ref_bh.
* If refcount reaches 0, remove it.
*/
static int ocfs2_change_refcount_rec(handle_t *handle,
struct ocfs2_caching_info *ci,
struct buffer_head *ref_leaf_bh,
Expand All @@ -1079,7 +1083,8 @@ static int ocfs2_change_refcount_rec(handle_t *handle,
int ret;
struct ocfs2_refcount_block *rb =
(struct ocfs2_refcount_block *)ref_leaf_bh->b_data;
struct ocfs2_refcount_rec *rec = &rb->rf_records.rl_recs[index];
struct ocfs2_refcount_list *rl = &rb->rf_records;
struct ocfs2_refcount_rec *rec = &rl->rl_recs[index];

ret = ocfs2_journal_access_rb(handle, ci, ref_leaf_bh,
OCFS2_JOURNAL_ACCESS_WRITE);
Expand All @@ -1092,7 +1097,18 @@ static int ocfs2_change_refcount_rec(handle_t *handle,
le32_to_cpu(rec->r_refcount), change);
le32_add_cpu(&rec->r_refcount, change);

ocfs2_refcount_rec_merge(rb, index);
if (!rec->r_refcount) {
if (index != le16_to_cpu(rl->rl_used) - 1) {
memmove(rec, rec + 1,
(le16_to_cpu(rl->rl_used) - index - 1) *
sizeof(struct ocfs2_refcount_rec));
memset(&rl->rl_recs[le16_to_cpu(rl->rl_used) - 1],
0, sizeof(struct ocfs2_refcount_rec));
}

le16_add_cpu(&rl->rl_used, -1);
} else
ocfs2_refcount_rec_merge(rb, index);

ret = ocfs2_journal_dirty(handle, ref_leaf_bh);
if (ret)
Expand Down Expand Up @@ -1901,3 +1917,239 @@ static int __ocfs2_increase_refcount(handle_t *handle,
brelse(ref_leaf_bh);
return ret;
}

static int ocfs2_remove_refcount_extent(handle_t *handle,
struct ocfs2_caching_info *ci,
struct buffer_head *ref_root_bh,
struct buffer_head *ref_leaf_bh,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret;
struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
struct ocfs2_refcount_block *rb =
(struct ocfs2_refcount_block *)ref_leaf_bh->b_data;
struct ocfs2_extent_tree et;

BUG_ON(rb->rf_records.rl_used);

ocfs2_init_refcount_extent_tree(&et, ci, ref_root_bh);
ret = ocfs2_remove_extent(handle, &et, le32_to_cpu(rb->rf_cpos),
1, meta_ac, dealloc);
if (ret) {
mlog_errno(ret);
goto out;
}

ocfs2_remove_from_cache(ci, ref_leaf_bh);

/*
* add the freed block to the dealloc so that it will be freed
* when we run dealloc.
*/
ret = ocfs2_cache_block_dealloc(dealloc, EXTENT_ALLOC_SYSTEM_INODE,
le16_to_cpu(rb->rf_suballoc_slot),
le64_to_cpu(rb->rf_blkno),
le16_to_cpu(rb->rf_suballoc_bit));
if (ret) {
mlog_errno(ret);
goto out;
}

ret = ocfs2_journal_access_rb(handle, ci, ref_root_bh,
OCFS2_JOURNAL_ACCESS_WRITE);
if (ret) {
mlog_errno(ret);
goto out;
}

rb = (struct ocfs2_refcount_block *)ref_root_bh->b_data;

le32_add_cpu(&rb->rf_clusters, -1);

/*
* check whether we need to restore the root refcount block if
* there is no leaf extent block at atll.
*/
if (!rb->rf_list.l_next_free_rec) {
BUG_ON(rb->rf_clusters);

mlog(0, "reset refcount tree root %llu to be a record block.\n",
(unsigned long long)ref_root_bh->b_blocknr);

rb->rf_flags = 0;
rb->rf_parent = 0;
rb->rf_cpos = 0;
memset(&rb->rf_records, 0, sb->s_blocksize -
offsetof(struct ocfs2_refcount_block, rf_records));
rb->rf_records.rl_count =
cpu_to_le16(ocfs2_refcount_recs_per_rb(sb));
}

ocfs2_journal_dirty(handle, ref_root_bh);

out:
return ret;
}

static int ocfs2_decrease_refcount_rec(handle_t *handle,
struct ocfs2_caching_info *ci,
struct buffer_head *ref_root_bh,
struct buffer_head *ref_leaf_bh,
int index, u64 cpos, unsigned int len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret;
struct ocfs2_refcount_block *rb =
(struct ocfs2_refcount_block *)ref_leaf_bh->b_data;
struct ocfs2_refcount_rec *rec = &rb->rf_records.rl_recs[index];

BUG_ON(cpos < le64_to_cpu(rec->r_cpos));
BUG_ON(cpos + len >
le64_to_cpu(rec->r_cpos) + le32_to_cpu(rec->r_clusters));

if (cpos == le64_to_cpu(rec->r_cpos) &&
len == le32_to_cpu(rec->r_clusters))
ret = ocfs2_change_refcount_rec(handle, ci,
ref_leaf_bh, index, -1);
else {
struct ocfs2_refcount_rec split = *rec;
split.r_cpos = cpu_to_le64(cpos);
split.r_clusters = cpu_to_le32(len);

le32_add_cpu(&split.r_refcount, -1);

mlog(0, "split refcount rec, start %llu, "
"len %u, count %u, original start %llu, len %u\n",
(unsigned long long)le64_to_cpu(split.r_cpos),
len, le32_to_cpu(split.r_refcount),
(unsigned long long)le64_to_cpu(rec->r_cpos),
le32_to_cpu(rec->r_clusters));
ret = ocfs2_split_refcount_rec(handle, ci,
ref_root_bh, ref_leaf_bh,
&split, index,
meta_ac, dealloc);
}

if (ret) {
mlog_errno(ret);
goto out;
}

/* Remove the leaf refcount block if it contains no refcount record. */
if (!rb->rf_records.rl_used && ref_leaf_bh != ref_root_bh) {
ret = ocfs2_remove_refcount_extent(handle, ci, ref_root_bh,
ref_leaf_bh, meta_ac,
dealloc);
if (ret)
mlog_errno(ret);
}

out:
return ret;
}

static int __ocfs2_decrease_refcount(handle_t *handle,
struct ocfs2_caching_info *ci,
struct buffer_head *ref_root_bh,
u64 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret = 0, index = 0;
struct ocfs2_refcount_rec rec;
unsigned int r_count = 0, r_len;
struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
struct buffer_head *ref_leaf_bh = NULL;

mlog(0, "Tree owner %llu, decrease refcount start %llu, len %u\n",
(unsigned long long)ocfs2_metadata_cache_owner(ci),
(unsigned long long)cpos, len);

while (len) {
ret = ocfs2_get_refcount_rec(ci, ref_root_bh,
cpos, len, &rec, &index,
&ref_leaf_bh);
if (ret) {
mlog_errno(ret);
goto out;
}

r_count = le32_to_cpu(rec.r_refcount);
BUG_ON(r_count == 0);

r_len = min((u64)(cpos + len), le64_to_cpu(rec.r_cpos) +
le32_to_cpu(rec.r_clusters)) - cpos;

ret = ocfs2_decrease_refcount_rec(handle, ci, ref_root_bh,
ref_leaf_bh, index,
cpos, r_len,
meta_ac, dealloc);
if (ret) {
mlog_errno(ret);
goto out;
}

if (le32_to_cpu(rec.r_refcount) == 1) {
ret = ocfs2_cache_cluster_dealloc(dealloc,
ocfs2_clusters_to_blocks(sb, cpos),
r_len);
if (ret) {
mlog_errno(ret);
goto out;
}
}

cpos += r_len;
len -= r_len;
brelse(ref_leaf_bh);
ref_leaf_bh = NULL;
}

out:
brelse(ref_leaf_bh);
return ret;
}

/* Caller must hold refcount tree lock. */
int ocfs2_decrease_refcount(struct inode *inode,
handle_t *handle, u32 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret;
u64 ref_blkno;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct buffer_head *ref_root_bh = NULL;
struct ocfs2_refcount_tree *tree;

BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));

ret = ocfs2_get_refcount_block(inode, &ref_blkno);
if (ret) {
mlog_errno(ret);
goto out;
}

ret = ocfs2_get_refcount_tree(OCFS2_SB(inode->i_sb), ref_blkno, &tree);
if (ret) {
mlog_errno(ret);
goto out;
}

ret = ocfs2_read_refcount_block(&tree->rf_ci, tree->rf_blkno,
&ref_root_bh);
if (ret) {
mlog_errno(ret);
goto out;
}

ret = __ocfs2_decrease_refcount(handle, &tree->rf_ci, ref_root_bh,
cpos, len, meta_ac, dealloc);
if (ret)
mlog_errno(ret);
out:
brelse(ref_root_bh);
return ret;
}
5 changes: 5 additions & 0 deletions fs/ocfs2/refcounttree.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,4 +40,9 @@ int ocfs2_lock_refcount_tree(struct ocfs2_super *osb, u64 ref_blkno, int rw,
void ocfs2_unlock_refcount_tree(struct ocfs2_super *osb,
struct ocfs2_refcount_tree *tree,
int rw);

int ocfs2_decrease_refcount(struct inode *inode,
handle_t *handle, u32 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
#endif /* OCFS2_REFCOUNTTREE_H */

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