ocfs2: Add xattr bucket iteration for large numbers of EAs
Ocfs2 breaks up xattr index tree leaves into 4k regions, called buckets.
Attributes are stored within a given bucket, depending on hash value.
After a discussion with Mark, we decided that the per-bucket index
(xe_entry[]) would only exist in the 1st block of a bucket. Likewise,
name/value pairs will not straddle more than one block. This allows the
majority of operations to work directly on the buffer heads in a leaf block.
This patch adds code to iterate the buckets in an EA. A new abstration of
ocfs2_xattr_bucket is added. It records the bhs in this bucket and
ocfs2_xattr_header. This keeps the code neat, improving readibility.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 98e1f8b..8d5e72f 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -755,8 +755,13 @@
__le16 xh_count; /* contains the count of how
many records are in the
local xattr storage. */
- __le16 xh_reserved1;
- __le32 xh_reserved2;
+ __le16 xh_free_start; /* current offset for storing
+ xattr. */
+ __le16 xh_name_value_len; /* total length of name/value
+ length in this bucket. */
+ __le16 xh_num_buckets; /* bucket nums in one extent
+ record, only valid in the
+ first bucket. */
__le64 xh_csum;
struct ocfs2_xattr_entry xh_entries[0]; /* xattr entry list. */
};
@@ -793,6 +798,10 @@
#define OCFS2_XATTR_SIZE(size) (((size) + OCFS2_XATTR_ROUND) & \
~(OCFS2_XATTR_ROUND))
+#define OCFS2_XATTR_BUCKET_SIZE 4096
+#define OCFS2_XATTR_MAX_BLOCKS_PER_BUCKET (OCFS2_XATTR_BUCKET_SIZE \
+ / OCFS2_MIN_BLOCKSIZE)
+
/*
* On disk structure for xattr block.
*/
@@ -963,6 +972,17 @@
return 0;
}
+
+static inline u16 ocfs2_xattr_recs_per_xb(struct super_block *sb)
+{
+ int size;
+
+ size = sb->s_blocksize -
+ offsetof(struct ocfs2_xattr_block,
+ xb_attrs.xb_root.xt_list.l_recs);
+
+ return size / sizeof(struct ocfs2_extent_rec);
+}
#else
static inline int ocfs2_fast_symlink_chars(int blocksize)
{
@@ -1046,6 +1066,17 @@
return 0;
}
+
+static inline int ocfs2_xattr_recs_per_xb(int blocksize)
+{
+ int size;
+
+ size = blocksize -
+ offsetof(struct ocfs2_xattr_block,
+ xb_attrs.xb_root.xt_list.l_recs);
+
+ return size / sizeof(struct ocfs2_extent_rec);
+}
#endif /* __KERNEL__ */