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Subject[PATCH 10/45] ocfs2: Use buckets in ocfs2_xattr_bucket_find().
Date
From: Joel Becker <joel.becker@oracle.com>

Change the ocfs2_xattr_bucket_find() function to use ocfs2_xattr_bucket
as its abstraction. This makes for more efficient reads, as buckets are
linear blocks, and also has improved caching characteristics. It also
reads better.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
---
fs/ocfs2/xattr.c | 89 +++++++++++++++++++-----------------------------------
1 files changed, 31 insertions(+), 58 deletions(-)

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 766494e..46986c6 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -2248,7 +2248,7 @@ typedef int (xattr_bucket_func)(struct inode *inode,
void *para);

static int ocfs2_find_xe_in_bucket(struct inode *inode,
- struct buffer_head *header_bh,
+ struct ocfs2_xattr_bucket *bucket,
int name_index,
const char *name,
u32 name_hash,
@@ -2256,11 +2256,9 @@ static int ocfs2_find_xe_in_bucket(struct inode *inode,
int *found)
{
int i, ret = 0, cmp = 1, block_off, new_offset;
- struct ocfs2_xattr_header *xh =
- (struct ocfs2_xattr_header *)header_bh->b_data;
+ struct ocfs2_xattr_header *xh = bucket_xh(bucket);
size_t name_len = strlen(name);
struct ocfs2_xattr_entry *xe = NULL;
- struct buffer_head *name_bh = NULL;
char *xe_name;

/*
@@ -2291,19 +2289,8 @@ static int ocfs2_find_xe_in_bucket(struct inode *inode,
break;
}

- ret = ocfs2_read_block(inode, header_bh->b_blocknr + block_off,
- &name_bh);
- if (ret) {
- mlog_errno(ret);
- break;
- }
- xe_name = name_bh->b_data + new_offset;
-
- cmp = memcmp(name, xe_name, name_len);
- brelse(name_bh);
- name_bh = NULL;
-
- if (cmp == 0) {
+ xe_name = bucket_block(bucket, block_off) + new_offset;
+ if (!memcmp(name, xe_name, name_len)) {
*xe_index = i;
*found = 1;
ret = 0;
@@ -2333,39 +2320,42 @@ static int ocfs2_xattr_bucket_find(struct inode *inode,
struct ocfs2_xattr_search *xs)
{
int ret, found = 0;
- struct buffer_head *bh = NULL;
- struct buffer_head *lower_bh = NULL;
struct ocfs2_xattr_header *xh = NULL;
struct ocfs2_xattr_entry *xe = NULL;
u16 index = 0;
u16 blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
int low_bucket = 0, bucket, high_bucket;
+ struct ocfs2_xattr_bucket *search;
u32 last_hash;
- u64 blkno;
+ u64 blkno, lower_blkno = 0;

- ret = ocfs2_read_block(inode, p_blkno, &bh);
+ search = ocfs2_xattr_bucket_new(inode);
+ if (!search) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_read_xattr_bucket(search, p_blkno);
if (ret) {
mlog_errno(ret);
goto out;
}

- xh = (struct ocfs2_xattr_header *)bh->b_data;
+ xh = bucket_xh(search);
high_bucket = le16_to_cpu(xh->xh_num_buckets) - 1;
-
while (low_bucket <= high_bucket) {
- brelse(bh);
- bh = NULL;
- bucket = (low_bucket + high_bucket) / 2;
+ ocfs2_xattr_bucket_relse(search);

+ bucket = (low_bucket + high_bucket) / 2;
blkno = p_blkno + bucket * blk_per_bucket;
-
- ret = ocfs2_read_block(inode, blkno, &bh);
+ ret = ocfs2_read_xattr_bucket(search, blkno);
if (ret) {
mlog_errno(ret);
goto out;
}

- xh = (struct ocfs2_xattr_header *)bh->b_data;
+ xh = bucket_xh(search);
xe = &xh->xh_entries[0];
if (name_hash < le32_to_cpu(xe->xe_name_hash)) {
high_bucket = bucket - 1;
@@ -2382,10 +2372,8 @@ static int ocfs2_xattr_bucket_find(struct inode *inode,

last_hash = le32_to_cpu(xe->xe_name_hash);

- /* record lower_bh which may be the insert place. */
- brelse(lower_bh);
- lower_bh = bh;
- bh = NULL;
+ /* record lower_blkno which may be the insert place. */
+ lower_blkno = blkno;

if (name_hash > le32_to_cpu(xe->xe_name_hash)) {
low_bucket = bucket + 1;
@@ -2393,7 +2381,7 @@ static int ocfs2_xattr_bucket_find(struct inode *inode,
}

/* the searched xattr should reside in this bucket if exists. */
- ret = ocfs2_find_xe_in_bucket(inode, lower_bh,
+ ret = ocfs2_find_xe_in_bucket(inode, search,
name_index, name, name_hash,
&index, &found);
if (ret) {
@@ -2408,35 +2396,21 @@ static int ocfs2_xattr_bucket_find(struct inode *inode,
* When the xattr's hash value is in the gap of 2 buckets, we will
* always set it to the previous bucket.
*/
- if (!lower_bh) {
- /*
- * We can't find any bucket whose first name_hash is less
- * than the find name_hash.
- */
- BUG_ON(bh->b_blocknr != p_blkno);
- lower_bh = bh;
- bh = NULL;
+ if (!lower_blkno)
+ lower_blkno = p_blkno;
+
+ /* This should be in cache - we just read it during the search */
+ ret = ocfs2_read_xattr_bucket(xs->bucket, lower_blkno);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
}
- xs->bucket->bu_bhs[0] = lower_bh;
- lower_bh = NULL;

xs->header = bucket_xh(xs->bucket);
xs->base = bucket_block(xs->bucket, 0);
xs->end = xs->base + inode->i_sb->s_blocksize;

if (found) {
- /*
- * If we have found the xattr enty, read all the blocks in
- * this bucket.
- */
- ret = ocfs2_read_blocks(inode, bucket_blkno(xs->bucket) + 1,
- blk_per_bucket - 1, &xs->bucket->bu_bhs[1],
- 0);
- if (ret) {
- mlog_errno(ret);
- goto out;
- }
-
xs->here = &xs->header->xh_entries[index];
mlog(0, "find xattr %s in bucket %llu, entry = %u\n", name,
(unsigned long long)bucket_blkno(xs->bucket), index);
@@ -2444,8 +2418,7 @@ static int ocfs2_xattr_bucket_find(struct inode *inode,
ret = -ENODATA;

out:
- brelse(bh);
- brelse(lower_bh);
+ ocfs2_xattr_bucket_free(search);
return ret;
}

--
1.5.6


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