ocfs2: Add xattr lookup code xattr btrees
authorTao Ma <tao.ma@oracle.com>
Mon, 18 Aug 2008 09:38:51 +0000 (17:38 +0800)
committerMark Fasheh <mfasheh@suse.com>
Mon, 13 Oct 2008 23:57:03 +0000 (16:57 -0700)
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

index fb17f7f..acccdfa 100644 (file)
@@ -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,