[Ocfs2-devel] [PATCH 01/42] ocfs2: Reused freed extent block in b-tree operation.
Tao Ma
tao.ma at oracle.com
Thu Mar 26 16:02:07 PDT 2009
In some b-tree operations we may have the chance that we haven't
reserved any metadata at the beginning because we think we don't
need. While the 1st operation free a extent block while the 2nd
operation need one. Our current code can't handle this. So this
patch try to re-use the freed extent block so that we can pass
the scenario above. For more details about the bug, see
[RFC] metadata alloc fix in machines which has PAGE_SIZE > CLUSTER_SIZE
http://oss.oracle.com/pipermail/ocfs2-devel/2009-March/004185.html.
I have sent out the patch before. See
http://oss.oracle.com/pipermail/ocfs2-devel/2009-March/004192.html.
This patch is extremely important for reflink operation since when we
reflink a file, we may touch a series fo extent record in one transaction,
and we meet with it easily and frequently.
Signed-off-by: Tao Ma <tao.ma at oracle.com>
---
fs/ocfs2/alloc.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++--
fs/ocfs2/alloc.h | 7 +++++++
fs/ocfs2/suballoc.c | 23 +++++++++++++++++++++++
fs/ocfs2/suballoc.h | 3 +++
fs/ocfs2/xattr.c | 6 +++---
5 files changed, 83 insertions(+), 5 deletions(-)
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index cb23d12..c63a7c5 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -893,7 +893,7 @@ static int ocfs2_create_new_meta_bhs(handle_t *handle,
struct buffer_head *bhs[])
{
int count, status, i;
- u16 suballoc_bit_start;
+ u16 slot, suballoc_bit_start;
u32 num_got;
u64 first_blkno;
struct ocfs2_super *osb =
@@ -908,6 +908,7 @@ static int ocfs2_create_new_meta_bhs(handle_t *handle,
handle,
meta_ac,
wanted - count,
+ &slot,
&suballoc_bit_start,
&num_got,
&first_blkno);
@@ -939,7 +940,7 @@ static int ocfs2_create_new_meta_bhs(handle_t *handle,
strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE);
eb->h_blkno = cpu_to_le64(first_blkno);
eb->h_fs_generation = cpu_to_le32(osb->fs_generation);
- eb->h_suballoc_slot = cpu_to_le16(osb->slot_num);
+ eb->h_suballoc_slot = cpu_to_le16(slot);
eb->h_suballoc_bit = cpu_to_le16(suballoc_bit_start);
eb->h_list.l_count =
cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb));
@@ -4878,6 +4879,7 @@ static int __ocfs2_mark_extent_written(handle_t *handle,
struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
struct ocfs2_merge_ctxt ctxt;
struct ocfs2_extent_list *rightmost_el;
+ struct ocfs2_alloc_context local_meta_ac;
if (!(rec->e_flags & OCFS2_EXT_UNWRITTEN)) {
ret = -EIO;
@@ -4930,6 +4932,17 @@ static int __ocfs2_mark_extent_written(handle_t *handle,
split_index, ctxt.c_contig_type, ctxt.c_has_empty_extent,
ctxt.c_split_covers_rec);
+ /*
+ * init dealloc in meta_ac here so that we can reuse the freed extent
+ * block in case.
+ * If the caller doesn't give us a meta_ac, we just fake one and add
+ * dealloc in it.
+ */
+ if (!meta_ac) {
+ memset(&local_meta_ac, 0, sizeof(local_meta_ac));
+ meta_ac = &local_meta_ac;
+ }
+ meta_ac->dealloc = dealloc;
if (ctxt.c_contig_type == CONTIG_NONE) {
if (ctxt.c_split_covers_rec)
ret = ocfs2_replace_extent_rec(handle, et, path, el,
@@ -6140,6 +6153,38 @@ int ocfs2_cache_cluster_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
return ret;
}
+int ocfs2_claim_bit_from_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
+ u16 *slot, u16 *suballoc_bit,
+ unsigned int *num_bits, u64 *blkno)
+{
+ struct ocfs2_per_slot_free_list *fl = ctxt->c_first_suballocator;
+ struct ocfs2_cached_block_free *tmp;
+
+ if (!fl || !fl->f_first)
+ return -ENOMEM;
+
+ tmp = fl->f_first->free_next;
+
+ *slot = fl->f_slot;
+ *suballoc_bit = fl->f_first->free_bit;
+ *blkno = fl->f_first->free_blk;
+ *num_bits = 1;
+
+ mlog(0, "claim blkno %llu suballoc_bit %u, slot %u\n",
+ (unsigned long long)*blkno, *suballoc_bit, *slot);
+
+ kfree(fl->f_first);
+ fl->f_first = tmp;
+
+ /* Free the suballocator if there is none. */
+ if (!fl->f_first) {
+ ctxt->c_first_suballocator = fl->f_next_suballocator;
+ kfree(fl);
+ }
+
+ return 0;
+}
+
static int ocfs2_free_cached_clusters(struct ocfs2_super *osb,
struct ocfs2_cached_block_free *head)
{
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index 07f6315..cd80410 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -188,10 +188,17 @@ 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);
+static inline int ocfs2_dealloc_has_block(struct ocfs2_cached_dealloc_ctxt *c)
+{
+ return c->c_first_suballocator != NULL;
+}
static inline int ocfs2_dealloc_has_cluster(struct ocfs2_cached_dealloc_ctxt *c)
{
return c->c_global_allocator != NULL;
}
+int ocfs2_claim_bit_from_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
+ u16 *slot, u16 *suballoc_bit,
+ unsigned int *num_bits, u64 *blkno);
int ocfs2_run_deallocs(struct ocfs2_super *osb,
struct ocfs2_cached_dealloc_ctxt *ctxt);
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index f6712ab..0cee488 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1586,6 +1586,7 @@ int ocfs2_claim_metadata(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 bits_wanted,
+ u16 *slot,
u16 *suballoc_bit_start,
unsigned int *num_bits,
u64 *blkno_start)
@@ -1594,6 +1595,27 @@ int ocfs2_claim_metadata(struct ocfs2_super *osb,
u64 bg_blkno;
BUG_ON(!ac);
+
+ /*
+ * If there is no space reserved in ac, check whether we have
+ * free some before in dealloc. If yes, allocate one form it.
+ */
+ if (ac->ac_bits_wanted < (ac->ac_bits_given + bits_wanted)) {
+ mlog(0, "alloc context doesn't have enough meta data reserved. "
+ "It has %d, we need %u\n",
+ ac->ac_bits_given - ac->ac_bits_given, bits_wanted);
+ if (ac->dealloc && ocfs2_dealloc_has_block(ac->dealloc)) {
+ status = ocfs2_claim_bit_from_dealloc(ac->dealloc,
+ slot,
+ suballoc_bit_start,
+ num_bits,
+ blkno_start);
+ if (!status)
+ goto bail;
+ /*fail through, so that it will BUG out. */
+ }
+ }
+
BUG_ON(ac->ac_bits_wanted < (ac->ac_bits_given + bits_wanted));
BUG_ON(ac->ac_which != OCFS2_AC_USE_META);
@@ -1611,6 +1633,7 @@ int ocfs2_claim_metadata(struct ocfs2_super *osb,
}
atomic_inc(&osb->alloc_stats.bg_allocs);
+ *slot = ac->ac_alloc_slot;
*blkno_start = bg_blkno + (u64) *suballoc_bit_start;
ac->ac_bits_given += (*num_bits);
status = 0;
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index e3c13c7..d271a12 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -34,6 +34,7 @@ typedef int (group_search_t)(struct inode *,
u16 *, /* *bit_off */
u16 *); /* *bits_found */
+struct ocfs2_cached_dealloc_ctxt;
struct ocfs2_alloc_context {
struct inode *ac_inode; /* which bitmap are we allocating from? */
struct buffer_head *ac_bh; /* file entry bh */
@@ -54,6 +55,7 @@ struct ocfs2_alloc_context {
u64 ac_last_group;
u64 ac_max_block; /* Highest block number to allocate. 0 is
is the same as ~0 - unlimited */
+ struct ocfs2_cached_dealloc_ctxt *dealloc;
};
void ocfs2_free_alloc_context(struct ocfs2_alloc_context *ac);
@@ -83,6 +85,7 @@ int ocfs2_claim_metadata(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 bits_wanted,
+ u16 *slot,
u16 *suballoc_bit_start,
u32 *num_bits,
u64 *blkno_start);
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 127e9d2..f324c65 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -2093,7 +2093,7 @@ static int ocfs2_xattr_block_set(struct inode *inode,
struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
handle_t *handle = ctxt->handle;
struct ocfs2_xattr_block *xblk = NULL;
- u16 suballoc_bit_start;
+ u16 slot, suballoc_bit_start;
u32 num_got;
u64 first_blkno;
int ret;
@@ -2108,7 +2108,7 @@ static int ocfs2_xattr_block_set(struct inode *inode,
}
ret = ocfs2_claim_metadata(osb, handle, ctxt->meta_ac, 1,
- &suballoc_bit_start, &num_got,
+ &slot, &suballoc_bit_start, &num_got,
&first_blkno);
if (ret < 0) {
mlog_errno(ret);
@@ -2131,7 +2131,7 @@ static int ocfs2_xattr_block_set(struct inode *inode,
xblk = (struct ocfs2_xattr_block *)new_bh->b_data;
memset(xblk, 0, inode->i_sb->s_blocksize);
strcpy((void *)xblk, OCFS2_XATTR_BLOCK_SIGNATURE);
- xblk->xb_suballoc_slot = cpu_to_le16(osb->slot_num);
+ xblk->xb_suballoc_slot = cpu_to_le16(slot);
xblk->xb_suballoc_bit = cpu_to_le16(suballoc_bit_start);
xblk->xb_fs_generation = cpu_to_le32(osb->fs_generation);
xblk->xb_blkno = cpu_to_le64(first_blkno);
--
1.6.2.rc2.16.gf474c
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