}
/*
- * Move half num of the xattrs in old bucket(blk) to new bucket(new_blk).
+ * Find the suitable pos when we divide a bucket into 2.
+ * We have to make sure the xattrs with the same hash value exist
+ * in the same bucket.
+ *
+ * If this ocfs2_xattr_header covers more than one hash value, find a
+ * place where the hash value changes. Try to find the most even split.
+ * The most common case is that all entries have different hash values,
+ * and the first check we make will find a place to split.
+ */
+static int ocfs2_xattr_find_divide_pos(struct ocfs2_xattr_header *xh)
+{
+ struct ocfs2_xattr_entry *entries = xh->xh_entries;
+ int count = le16_to_cpu(xh->xh_count);
+ int delta, middle = count / 2;
+
+ /*
+ * We start at the middle. Each step gets farther away in both
+ * directions. We therefore hit the change in hash value
+ * nearest to the middle. Note that this loop does not execute for
+ * count < 2.
+ */
+ for (delta = 0; delta < middle; delta++) {
+ /* Let's check delta earlier than middle */
+ if (cmp_xe(&entries[middle - delta - 1],
+ &entries[middle - delta]))
+ return middle - delta;
+
+ /* For even counts, don't walk off the end */
+ if ((middle + delta + 1) == count)
+ continue;
+
+ /* Now try delta past middle */
+ if (cmp_xe(&entries[middle + delta],
+ &entries[middle + delta + 1]))
+ return middle + delta + 1;
+ }
+
+ /* Every entry had the same hash */
+ return count;
+}
+
+/*
+ * Move some xattrs in old bucket(blk) to new bucket(new_blk).
* first_hash will record the 1st hash of the new bucket.
+ *
+ * Normally half of the xattrs will be moved. But we have to make
+ * sure that the xattrs with the same hash value are stored in the
+ * same bucket. If all the xattrs in this bucket have the same hash
+ * value, the new bucket will be initialized as an empty one and the
+ * first_hash will be initialized as (hash_value+1).
*/
-static int ocfs2_half_xattr_bucket(struct inode *inode,
- handle_t *handle,
- u64 blk,
- u64 new_blk,
- u32 *first_hash,
- int new_bucket_head)
+static int ocfs2_divide_xattr_bucket(struct inode *inode,
+ handle_t *handle,
+ u64 blk,
+ u64 new_blk,
+ u32 *first_hash,
+ int new_bucket_head)
{
int ret, i;
- u16 count, start, len, name_value_len, xe_len, name_offset;
+ int count, start, len, name_value_len = 0, xe_len, name_offset = 0;
u16 blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
struct buffer_head **s_bhs, **t_bhs = NULL;
struct ocfs2_xattr_header *xh;
struct ocfs2_xattr_entry *xe;
int blocksize = inode->i_sb->s_blocksize;
- mlog(0, "move half of xattrs from bucket %llu to %llu\n",
+ mlog(0, "move some of xattrs from bucket %llu to %llu\n",
blk, new_blk);
s_bhs = kcalloc(blk_per_bucket, sizeof(struct buffer_head *), GFP_NOFS);
}
}
+ xh = (struct ocfs2_xattr_header *)s_bhs[0]->b_data;
+ count = le16_to_cpu(xh->xh_count);
+ start = ocfs2_xattr_find_divide_pos(xh);
+
+ if (start == count) {
+ xe = &xh->xh_entries[start-1];
+
+ /*
+ * initialized a new empty bucket here.
+ * The hash value is set as one larger than
+ * that of the last entry in the previous bucket.
+ */
+ for (i = 0; i < blk_per_bucket; i++)
+ memset(t_bhs[i]->b_data, 0, blocksize);
+
+ xh = (struct ocfs2_xattr_header *)t_bhs[0]->b_data;
+ xh->xh_free_start = cpu_to_le16(blocksize);
+ xh->xh_entries[0].xe_name_hash = xe->xe_name_hash;
+ le32_add_cpu(&xh->xh_entries[0].xe_name_hash, 1);
+
+ goto set_num_buckets;
+ }
+
/* copy the whole bucket to the new first. */
for (i = 0; i < blk_per_bucket; i++)
memcpy(t_bhs[i]->b_data, s_bhs[i]->b_data, blocksize);
/* update the new bucket. */
xh = (struct ocfs2_xattr_header *)t_bhs[0]->b_data;
- count = le16_to_cpu(xh->xh_count);
- start = count / 2;
/*
* Calculate the total name/value len and xh_free_start for
xh->xh_free_start = xe->xe_name_offset;
}
+set_num_buckets:
/* set xh->xh_num_buckets for the new xh. */
if (new_bucket_head)
xh->xh_num_buckets = cpu_to_le16(1);
*first_hash = le32_to_cpu(xh->xh_entries[0].xe_name_hash);
/*
- * Now only update the 1st block of the old bucket.
- * Please note that the entry has been sorted already above.
+ * Now only update the 1st block of the old bucket. If we
+ * just added a new empty bucket, there is no need to modify
+ * it.
*/
+ if (start == count)
+ goto out;
+
xh = (struct ocfs2_xattr_header *)s_bhs[0]->b_data;
memset(&xh->xh_entries[start], 0,
sizeof(struct ocfs2_xattr_entry) * (count - start));
}
/*
- * Move half of the xattrs in this cluster to the new cluster.
+ * Move some xattrs in this cluster to the new cluster.
* This function should only be called when bucket size == cluster size.
* Otherwise ocfs2_mv_xattr_bucket_cross_cluster should be used instead.
*/
-static int ocfs2_half_xattr_cluster(struct inode *inode,
- handle_t *handle,
- u64 prev_blk,
- u64 new_blk,
- u32 *first_hash)
+static int ocfs2_divide_xattr_cluster(struct inode *inode,
+ handle_t *handle,
+ u64 prev_blk,
+ u64 new_blk,
+ u32 *first_hash)
{
u16 blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
int ret, credits = 2 * blk_per_bucket;
}
/* Move half of the xattr in start_blk to the next bucket. */
- return ocfs2_half_xattr_bucket(inode, handle, prev_blk,
- new_blk, first_hash, 1);
+ return ocfs2_divide_xattr_bucket(inode, handle, prev_blk,
+ new_blk, first_hash, 1);
}
/*
last_blk, new_blk,
v_start);
else {
- ret = ocfs2_half_xattr_cluster(inode, handle,
- last_blk, new_blk,
- v_start);
+ ret = ocfs2_divide_xattr_cluster(inode, handle,
+ last_blk, new_blk,
+ v_start);
if ((*header_bh)->b_blocknr == last_blk && extend)
*extend = 0;
}
/* Move half of the xattr in start_blk to the next bucket. */
- ret = ocfs2_half_xattr_bucket(inode, handle, start_blk,
- start_blk + blk_per_bucket, NULL, 0);
+ ret = ocfs2_divide_xattr_bucket(inode, handle, start_blk,
+ start_blk + blk_per_bucket, NULL, 0);
le16_add_cpu(&first_xh->xh_num_buckets, 1);
ocfs2_journal_dirty(handle, first_bh);
return ret;
}
-/* check whether the xattr bucket is filled up with the same hash value. */
+/*
+ * check whether the xattr bucket is filled up with the same hash value.
+ * If we want to insert the xattr with the same hash, return -ENOSPC.
+ * If we want to insert a xattr with different hash value, go ahead
+ * and ocfs2_divide_xattr_bucket will handle this.
+ */
static int ocfs2_check_xattr_bucket_collision(struct inode *inode,
- struct ocfs2_xattr_bucket *bucket)
+ struct ocfs2_xattr_bucket *bucket,
+ const char *name)
{
struct ocfs2_xattr_header *xh = bucket->xh;
+ u32 name_hash = ocfs2_xattr_name_hash(inode, name, strlen(name));
+
+ if (name_hash != le32_to_cpu(xh->xh_entries[0].xe_name_hash))
+ return 0;
if (xh->xh_entries[le16_to_cpu(xh->xh_count) - 1].xe_name_hash ==
xh->xh_entries[0].xe_name_hash) {
* one bucket's worth, so check it here whether we need to
* add a new bucket for the insert.
*/
- ret = ocfs2_check_xattr_bucket_collision(inode, &xs->bucket);
+ ret = ocfs2_check_xattr_bucket_collision(inode,
+ &xs->bucket,
+ xi->name);
if (ret) {
mlog_errno(ret);
goto out;
projects / profile / ivi / kernel-x86-ivi.git / commitdiff