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Subject[PATCH 16/39] ocfs2: Add xattr lookup code xattr btrees
Date
From: Tao Ma <tao.ma@oracle.com>

Add code to lookup a given extended attribute in the xattr btree. Lookup
follows this general scheme:

1. Use ocfs2_xattr_get_rec to find the xattr extent record

2. Find the xattr bucket within the extent which may contain this xattr

3. Iterate the bucket to find the xattr. In ocfs2_xattr_block_get(), we need
to recalcuate the block offset and name offset for the right position of
name/value.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
---
fs/ocfs2/xattr.c | 351 ++++++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 328 insertions(+), 23 deletions(-)
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index fb17f7f..acccdfa 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -99,12 +99,25 @@ struct ocfs2_xattr_search {
*/
struct buffer_head *xattr_bh;
struct ocfs2_xattr_header *header;
+ struct ocfs2_xattr_bucket bucket;
void *base;
void *end;
struct ocfs2_xattr_entry *here;
int not_found;
};

+static int ocfs2_xattr_bucket_get_name_value(struct inode *inode,
+ struct ocfs2_xattr_header *xh,
+ int index,
+ int *block_off,
+ int *new_offset);
+
+static int ocfs2_xattr_index_block_find(struct inode *inode,
+ struct buffer_head *root_bh,
+ int name_index,
+ const char *name,
+ struct ocfs2_xattr_search *xs);
+
static int ocfs2_xattr_tree_list_index_block(struct inode *inode,
struct ocfs2_xattr_tree_root *xt,
char *buffer,
@@ -604,7 +617,7 @@ static int ocfs2_xattr_find_entry(int name_index,
}

static int ocfs2_xattr_get_value_outside(struct inode *inode,
- struct ocfs2_xattr_search *xs,
+ struct ocfs2_xattr_value_root *xv,
void *buffer,
size_t len)
{
@@ -613,12 +626,8 @@ static int ocfs2_xattr_get_value_outside(struct inode *inode,
int i, ret = 0;
size_t cplen, blocksize;
struct buffer_head *bh = NULL;
- struct ocfs2_xattr_value_root *xv;
struct ocfs2_extent_list *el;

- xv = (struct ocfs2_xattr_value_root *)
- (xs->base + le16_to_cpu(xs->here->xe_name_offset) +
- OCFS2_XATTR_SIZE(xs->here->xe_name_len));
el = &xv->xr_list;
clusters = le32_to_cpu(xv->xr_clusters);
bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
@@ -668,6 +677,7 @@ static int ocfs2_xattr_ibody_get(struct inode *inode,
{
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
+ struct ocfs2_xattr_value_root *xv;
size_t size;
int ret = 0;

@@ -692,7 +702,11 @@ static int ocfs2_xattr_ibody_get(struct inode *inode,
le16_to_cpu(xs->here->xe_name_offset) +
OCFS2_XATTR_SIZE(xs->here->xe_name_len), size);
} else {
- ret = ocfs2_xattr_get_value_outside(inode, xs,
+ xv = (struct ocfs2_xattr_value_root *)
+ (xs->base + le16_to_cpu(
+ xs->here->xe_name_offset) +
+ OCFS2_XATTR_SIZE(xs->here->xe_name_len));
+ ret = ocfs2_xattr_get_value_outside(inode, xv,
buffer, size);
if (ret < 0) {
mlog_errno(ret);
@@ -714,12 +728,15 @@ static int ocfs2_xattr_block_get(struct inode *inode,
struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
struct buffer_head *blk_bh = NULL;
struct ocfs2_xattr_block *xb;
+ struct ocfs2_xattr_value_root *xv;
size_t size;
- int ret = -ENODATA;
+ int ret = -ENODATA, name_offset, name_len, block_off, i;

if (!di->i_xattr_loc)
return ret;

+ memset(&xs->bucket, 0, sizeof(xs->bucket));
+
ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
le64_to_cpu(di->i_xattr_loc),
&blk_bh, OCFS2_BH_CACHED, inode);
@@ -736,12 +753,19 @@ static int ocfs2_xattr_block_get(struct inode *inode,

xs->xattr_bh = blk_bh;
xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
- xs->header = &xb->xb_attrs.xb_header;
- xs->base = (void *)xs->header;
- xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size;
- xs->here = xs->header->xh_entries;

- ret = ocfs2_xattr_find_entry(name_index, name, xs);
+ if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
+ xs->header = &xb->xb_attrs.xb_header;
+ xs->base = (void *)xs->header;
+ xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size;
+ xs->here = xs->header->xh_entries;
+
+ ret = ocfs2_xattr_find_entry(name_index, name, xs);
+ } else
+ ret = ocfs2_xattr_index_block_find(inode, blk_bh,
+ name_index,
+ name, xs);
+
if (ret)
goto cleanup;
size = le64_to_cpu(xs->here->xe_value_size);
@@ -749,12 +773,26 @@ static int ocfs2_xattr_block_get(struct inode *inode,
ret = -ERANGE;
if (size > buffer_size)
goto cleanup;
+
+ name_offset = le16_to_cpu(xs->here->xe_name_offset);
+ name_len = OCFS2_XATTR_SIZE(xs->here->xe_name_len);
+ i = xs->here - xs->header->xh_entries;
+
+ if (le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED) {
+ ret = ocfs2_xattr_bucket_get_name_value(inode,
+ xs->bucket.xh,
+ i,
+ &block_off,
+ &name_offset);
+ xs->base = xs->bucket.bhs[block_off]->b_data;
+ }
if (ocfs2_xattr_is_local(xs->here)) {
memcpy(buffer, (void *)xs->base +
- le16_to_cpu(xs->here->xe_name_offset) +
- OCFS2_XATTR_SIZE(xs->here->xe_name_len), size);
+ name_offset + name_len, size);
} else {
- ret = ocfs2_xattr_get_value_outside(inode, xs,
+ xv = (struct ocfs2_xattr_value_root *)
+ (xs->base + name_offset + name_len);
+ ret = ocfs2_xattr_get_value_outside(inode, xv,
buffer, size);
if (ret < 0) {
mlog_errno(ret);
@@ -764,8 +802,11 @@ static int ocfs2_xattr_block_get(struct inode *inode,
}
ret = size;
cleanup:
- brelse(blk_bh);
+ for (i = 0; i < OCFS2_XATTR_MAX_BLOCKS_PER_BUCKET; i++)
+ brelse(xs->bucket.bhs[i]);
+ memset(&xs->bucket, 0, sizeof(xs->bucket));

+ brelse(blk_bh);
return ret;
}

@@ -1679,6 +1720,7 @@ static int ocfs2_xattr_block_find(struct inode *inode,
{
struct ocfs2_dinode *di = (struct ocfs2_dinode *)xs->inode_bh->b_data;
struct buffer_head *blk_bh = NULL;
+ struct ocfs2_xattr_block *xb;
int ret = 0;

if (!di->i_xattr_loc)
@@ -1699,20 +1741,26 @@ static int ocfs2_xattr_block_find(struct inode *inode,
}

xs->xattr_bh = blk_bh;
- xs->header = &((struct ocfs2_xattr_block *)blk_bh->b_data)->
- xb_attrs.xb_header;
- xs->base = (void *)xs->header;
- xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size;
- xs->here = xs->header->xh_entries;
+ xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
+
+ if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
+ xs->header = &xb->xb_attrs.xb_header;
+ xs->base = (void *)xs->header;
+ xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size;
+ xs->here = xs->header->xh_entries;
+
+ ret = ocfs2_xattr_find_entry(name_index, name, xs);
+ } else
+ ret = ocfs2_xattr_index_block_find(inode, blk_bh,
+ name_index,
+ name, xs);

- ret = ocfs2_xattr_find_entry(name_index, name, xs);
if (ret && ret != -ENODATA) {
xs->xattr_bh = NULL;
goto cleanup;
}
xs->not_found = ret;
return 0;
-
cleanup:
brelse(blk_bh);

@@ -1941,6 +1989,18 @@ cleanup:
return ret;
}

+static inline u32 ocfs2_xattr_hash_by_name(struct inode *inode,
+ int name_index,
+ const char *suffix_name)
+{
+ struct xattr_handler *handler = ocfs2_xattr_handler(name_index);
+ char *prefix = handler->prefix;
+ int prefix_len = strlen(handler->prefix);
+
+ return ocfs2_xattr_name_hash(inode, prefix, prefix_len,
+ (char *)suffix_name, strlen(suffix_name));
+}
+
/*
* Find the xattr extent rec which may contains name_hash.
* e_cpos will be the first name hash of the xattr rec.
@@ -2010,6 +2070,251 @@ typedef int (xattr_bucket_func)(struct inode *inode,
struct ocfs2_xattr_bucket *bucket,
void *para);

+static int ocfs2_find_xe_in_bucket(struct inode *inode,
+ struct buffer_head *header_bh,
+ int name_index,
+ const char *name,
+ u32 name_hash,
+ u16 *xe_index,
+ 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;
+ size_t name_len = strlen(name);
+ struct ocfs2_xattr_entry *xe = NULL;
+ struct buffer_head *name_bh = NULL;
+ char *xe_name;
+
+ /*
+ * We don't use binary search in the bucket because there
+ * may be multiple entries with the same name hash.
+ */
+ for (i = 0; i < le16_to_cpu(xh->xh_count); i++) {
+ xe = &xh->xh_entries[i];
+
+ if (name_hash > le32_to_cpu(xe->xe_name_hash))
+ continue;
+ else if (name_hash < le32_to_cpu(xe->xe_name_hash))
+ break;
+
+ cmp = name_index - ocfs2_xattr_get_type(xe);
+ if (!cmp)
+ cmp = name_len - xe->xe_name_len;
+ if (cmp)
+ continue;
+
+ ret = ocfs2_xattr_bucket_get_name_value(inode,
+ xh,
+ i,
+ &block_off,
+ &new_offset);
+ if (ret) {
+ mlog_errno(ret);
+ break;
+ }
+
+ ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+ header_bh->b_blocknr + block_off,
+ &name_bh, OCFS2_BH_CACHED, inode);
+ 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_index = i;
+ *found = 1;
+ ret = 0;
+ break;
+ }
+ }
+
+ return ret;
+}
+
+/*
+ * Find the specified xattr entry in a series of buckets.
+ * This series start from p_blkno and last for num_clusters.
+ * The ocfs2_xattr_header.xh_num_buckets of the first bucket contains
+ * the num of the valid buckets.
+ *
+ * Return the buffer_head this xattr should reside in. And if the xattr's
+ * hash is in the gap of 2 buckets, return the lower bucket.
+ */
+static int ocfs2_xattr_bucket_find(struct inode *inode,
+ int name_index,
+ const char *name,
+ u32 name_hash,
+ u64 p_blkno,
+ u32 first_hash,
+ u32 num_clusters,
+ 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;
+ u32 last_hash;
+ u64 blkno;
+
+ ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), p_blkno,
+ &bh, OCFS2_BH_CACHED, inode);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ xh = (struct ocfs2_xattr_header *)bh->b_data;
+ 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;
+
+ blkno = p_blkno + bucket * blk_per_bucket;
+
+ ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno,
+ &bh, OCFS2_BH_CACHED, inode);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ xh = (struct ocfs2_xattr_header *)bh->b_data;
+ xe = &xh->xh_entries[0];
+ if (name_hash < le32_to_cpu(xe->xe_name_hash)) {
+ high_bucket = bucket - 1;
+ continue;
+ }
+
+ /*
+ * Check whether the hash of the last entry in our
+ * bucket is larger than the search one.
+ */
+ xe = &xh->xh_entries[le16_to_cpu(xh->xh_count) - 1];
+ 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;
+
+ if (name_hash > le32_to_cpu(xe->xe_name_hash)) {
+ low_bucket = bucket + 1;
+ continue;
+ }
+
+ /* the searched xattr should reside in this bucket if exists. */
+ ret = ocfs2_find_xe_in_bucket(inode, lower_bh,
+ name_index, name, name_hash,
+ &index, &found);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ break;
+ }
+
+ /*
+ * Record the bucket we have found.
+ * 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;
+ }
+ xs->bucket.bhs[0] = lower_bh;
+ xs->bucket.xh = (struct ocfs2_xattr_header *)
+ xs->bucket.bhs[0]->b_data;
+ lower_bh = NULL;
+
+ xs->header = xs->bucket.xh;
+ xs->base = xs->bucket.bhs[0]->b_data;
+ 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(OCFS2_SB(inode->i_sb),
+ xs->bucket.bhs[0]->b_blocknr + 1,
+ blk_per_bucket - 1, &xs->bucket.bhs[1],
+ OCFS2_BH_CACHED, inode);
+ 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)xs->bucket.bhs[0]->b_blocknr, index);
+ } else
+ ret = -ENODATA;
+
+out:
+ brelse(bh);
+ brelse(lower_bh);
+ return ret;
+}
+
+static int ocfs2_xattr_index_block_find(struct inode *inode,
+ struct buffer_head *root_bh,
+ int name_index,
+ const char *name,
+ struct ocfs2_xattr_search *xs)
+{
+ int ret;
+ struct ocfs2_xattr_block *xb =
+ (struct ocfs2_xattr_block *)root_bh->b_data;
+ struct ocfs2_xattr_tree_root *xb_root = &xb->xb_attrs.xb_root;
+ struct ocfs2_extent_list *el = &xb_root->xt_list;
+ u64 p_blkno = 0;
+ u32 first_hash, num_clusters = 0;
+ u32 name_hash = ocfs2_xattr_hash_by_name(inode, name_index, name);
+
+ if (le16_to_cpu(el->l_next_free_rec) == 0)
+ return -ENODATA;
+
+ mlog(0, "find xattr %s, hash = %u, index = %d in xattr tree\n",
+ name, name_hash, name_index);
+
+ ret = ocfs2_xattr_get_rec(inode, name_hash, &p_blkno, &first_hash,
+ &num_clusters, el);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ BUG_ON(p_blkno == 0 || num_clusters == 0 || first_hash > name_hash);
+
+ mlog(0, "find xattr extent rec %u clusters from %llu, the first hash "
+ "in the rec is %u\n", num_clusters, p_blkno, first_hash);
+
+ ret = ocfs2_xattr_bucket_find(inode, name_index, name, name_hash,
+ p_blkno, first_hash, num_clusters, xs);
+
+out:
+ return ret;
+}
+
static int ocfs2_iterate_xattr_buckets(struct inode *inode,
u64 blkno,
u32 clusters,
--
1.5.4.5


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