[PATCH 15/39] ocfs2: Add xattr bucket iteration for large numbers of EAs

Mark Fasheh
2008-09-24T22:08:17Z

From: Tao Ma <tao.ma@oracle.com>

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>
---
fs/ocfs2/ocfs2_fs.h | 35 +++++++-
fs/ocfs2/xattr.c | 255 ++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/ocfs2/xattr.h | 9 ++
3 files changed, 293 insertions(+), 6 deletions(-)

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 @@ struct ocfs2_xattr_header {
__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 @@ struct ocfs2_xattr_tree_root {
#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 @@ static inline u64 ocfs2_backup_super_blkno(struct super_block *sb, int index)
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 @@ static inline uint64_t ocfs2_backup_super_blkno(int blocksize, int index)

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__ */

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 67bebd9..fb17f7f 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -52,6 +52,7 @@
#include "suballoc.h"
#include "uptodate.h"
#include "buffer_head_io.h"
+#include "super.h"
#include "xattr.h"

@@ -60,6 +61,11 @@ struct ocfs2_xattr_def_value_root {
struct ocfs2_extent_rec er;
};

+struct ocfs2_xattr_bucket {
+ struct buffer_head *bhs[OCFS2_XATTR_MAX_BLOCKS_PER_BUCKET];
+ struct ocfs2_xattr_header *xh;
+};
+
#define OCFS2_XATTR_ROOT_SIZE (sizeof(struct ocfs2_xattr_def_value_root))
#define OCFS2_XATTR_INLINE_SIZE 80

@@ -99,6 +105,11 @@ struct ocfs2_xattr_search {
int not_found;
};

+static int ocfs2_xattr_tree_list_index_block(struct inode *inode,
+ struct ocfs2_xattr_tree_root *xt,
+ char *buffer,
+ size_t buffer_size);
+
static inline struct xattr_handler *ocfs2_xattr_handler(int name_index)
{
struct xattr_handler *handler = NULL;
@@ -483,7 +494,7 @@ static int ocfs2_xattr_block_list(struct inode *inode,
size_t buffer_size)
{
struct buffer_head *blk_bh = NULL;
- struct ocfs2_xattr_header *header = NULL;
+ struct ocfs2_xattr_block *xb;
int ret = 0;

if (!di->i_xattr_loc)
@@ -503,10 +514,17 @@ static int ocfs2_xattr_block_list(struct inode *inode,
goto cleanup;
}

- header = &((struct ocfs2_xattr_block *)blk_bh->b_data)->
- xb_attrs.xb_header;
+ xb = (struct ocfs2_xattr_block *)blk_bh->b_data;

- ret = ocfs2_xattr_list_entries(inode, header, buffer, buffer_size);
+ if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
+ struct ocfs2_xattr_header *header = &xb->xb_attrs.xb_header;
+ ret = ocfs2_xattr_list_entries(inode, header,
+ buffer, buffer_size);
+ } else {
+ struct ocfs2_xattr_tree_root *xt = &xb->xb_attrs.xb_root;
+ ret = ocfs2_xattr_tree_list_index_block(inode, xt,
+ buffer, buffer_size);
+ }
cleanup:
brelse(blk_bh);

@@ -1923,3 +1941,232 @@ cleanup:
return ret;
}

+/*
+ * Find the xattr extent rec which may contains name_hash.
+ * e_cpos will be the first name hash of the xattr rec.
+ * el must be the ocfs2_xattr_header.xb_attrs.xb_root.xt_list.
+ */
+static int ocfs2_xattr_get_rec(struct inode *inode,
+ u32 name_hash,
+ u64 *p_blkno,
+ u32 *e_cpos,
+ u32 *num_clusters,
+ struct ocfs2_extent_list *el)
+{
+ int ret = 0, i;
+ struct buffer_head *eb_bh = NULL;
+ struct ocfs2_extent_block *eb;
+ struct ocfs2_extent_rec *rec = NULL;
+ u64 e_blkno = 0;
+
+ if (el->l_tree_depth) {
+ ret = ocfs2_find_leaf(inode, el, name_hash, &eb_bh);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+ el = &eb->h_list;
+
+ if (el->l_tree_depth) {
+ ocfs2_error(inode->i_sb,
+ "Inode %lu has non zero tree depth in "
+ "xattr tree block %llu\n", inode->i_ino,
+ (unsigned long long)eb_bh->b_blocknr);
+ ret = -EROFS;
+ goto out;
+ }
+ }
+
+ for (i = le16_to_cpu(el->l_next_free_rec) - 1; i >= 0; i--) {
+ rec = &el->l_recs[i];
+
+ if (le32_to_cpu(rec->e_cpos) <= name_hash) {
+ e_blkno = le64_to_cpu(rec->e_blkno);
+ break;
+ }
+ }
+
+ if (!e_blkno) {
+ ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
+ "record (%u, %u, 0) in xattr", inode->i_ino,
+ le32_to_cpu(rec->e_cpos),
+ ocfs2_rec_clusters(el, rec));
+ ret = -EROFS;
+ goto out;
+ }
+
+ *p_blkno = le64_to_cpu(rec->e_blkno);
+ *num_clusters = le16_to_cpu(rec->e_leaf_clusters);
+ if (e_cpos)
+ *e_cpos = le32_to_cpu(rec->e_cpos);
+out:
+ brelse(eb_bh);
+ return ret;
+}
+
+typedef int (xattr_bucket_func)(struct inode *inode,
+ struct ocfs2_xattr_bucket *bucket,
+ void *para);
+
+static int ocfs2_iterate_xattr_buckets(struct inode *inode,
+ u64 blkno,
+ u32 clusters,
+ xattr_bucket_func *func,
+ void *para)
+{
+ int i, j, ret = 0;
+ int blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
+ u32 bpc = ocfs2_xattr_buckets_per_cluster(OCFS2_SB(inode->i_sb));
+ u32 num_buckets = clusters * bpc;
+ struct ocfs2_xattr_bucket bucket;
+
+ memset(&bucket, 0, sizeof(bucket));
+
+ mlog(0, "iterating xattr buckets in %u clusters starting from %llu\n",
+ clusters, blkno);
+
+ for (i = 0; i < num_buckets; i++, blkno += blk_per_bucket) {
+ ret = ocfs2_read_blocks(OCFS2_SB(inode->i_sb),
+ blkno, blk_per_bucket,
+ bucket.bhs, OCFS2_BH_CACHED, inode);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ bucket.xh = (struct ocfs2_xattr_header *)bucket.bhs[0]->b_data;
+ /*
+ * The real bucket num in this series of blocks is stored
+ * in the 1st bucket.
+ */
+ if (i == 0)
+ num_buckets = le16_to_cpu(bucket.xh->xh_num_buckets);
+
+ mlog(0, "iterating xattr bucket %llu\n", blkno);
+ if (func) {
+ ret = func(inode, &bucket, para);
+ if (ret) {
+ mlog_errno(ret);
+ break;
+ }
+ }
+
+ for (j = 0; j < blk_per_bucket; j++)
+ brelse(bucket.bhs[j]);
+ memset(&bucket, 0, sizeof(bucket));
+ }
+
+out:
+ for (j = 0; j < blk_per_bucket; j++)
+ brelse(bucket.bhs[j]);
+
+ return ret;
+}
+
+struct ocfs2_xattr_tree_list {
+ char *buffer;
+ size_t buffer_size;
+};
+
+static int ocfs2_xattr_bucket_get_name_value(struct inode *inode,
+ struct ocfs2_xattr_header *xh,
+ int index,
+ int *block_off,
+ int *new_offset)
+{
+ u16 name_offset;
+
+ if (index < 0 || index >= le16_to_cpu(xh->xh_count))
+ return -EINVAL;
+
+ name_offset = le16_to_cpu(xh->xh_entries[index].xe_name_offset);
+
+ *block_off = name_offset >> inode->i_sb->s_blocksize_bits;
+ *new_offset = name_offset % inode->i_sb->s_blocksize;
+
+ return 0;
+}
+
+static int ocfs2_list_xattr_bucket(struct inode *inode,
+ struct ocfs2_xattr_bucket *bucket,
+ void *para)
+{
+ int ret = 0;
+ struct ocfs2_xattr_tree_list *xl = (struct ocfs2_xattr_tree_list *)para;
+ size_t size;
+ int i, block_off, new_offset;
+
+ for (i = 0 ; i < le16_to_cpu(bucket->xh->xh_count); i++) {
+ struct ocfs2_xattr_entry *entry = &bucket->xh->xh_entries[i];
+ struct xattr_handler *handler =
+ ocfs2_xattr_handler(ocfs2_xattr_get_type(entry));
+
+ if (handler) {
+ ret = ocfs2_xattr_bucket_get_name_value(inode,
+ bucket->xh,
+ i,
+ &block_off,
+ &new_offset);
+ if (ret)
+ break;
+ size = handler->list(inode, xl->buffer, xl->buffer_size,
+ bucket->bhs[block_off]->b_data +
+ new_offset,
+ entry->xe_name_len);
+ if (xl->buffer) {
+ if (size > xl->buffer_size)
+ return -ERANGE;
+ xl->buffer += size;
+ }
+ xl->buffer_size -= size;
+ }
+ }
+
+ return ret;
+}
+
+static int ocfs2_xattr_tree_list_index_block(struct inode *inode,
+ struct ocfs2_xattr_tree_root *xt,
+ char *buffer,
+ size_t buffer_size)
+{
+ struct ocfs2_extent_list *el = &xt->xt_list;
+ int ret = 0;
+ u32 name_hash = UINT_MAX, e_cpos = 0, num_clusters = 0;
+ u64 p_blkno = 0;
+ struct ocfs2_xattr_tree_list xl = {
+ .buffer = buffer,
+ .buffer_size = buffer_size,
+ };
+
+ if (le16_to_cpu(el->l_next_free_rec) == 0)
+ return 0;
+
+ while (name_hash > 0) {
+ ret = ocfs2_xattr_get_rec(inode, name_hash, &p_blkno,
+ &e_cpos, &num_clusters, el);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_iterate_xattr_buckets(inode, p_blkno, num_clusters,
+ ocfs2_list_xattr_bucket,
+ &xl);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (e_cpos == 0)
+ break;
+
+ name_hash = e_cpos - 1;
+ }
+
+ ret = buffer_size - xl.buffer_size;
+out:
+ return ret;
+}
diff --git a/fs/ocfs2/xattr.h b/fs/ocfs2/xattr.h
index ed32377..02afa87 100644
--- a/fs/ocfs2/xattr.h
+++ b/fs/ocfs2/xattr.h
@@ -48,4 +48,13 @@ extern int ocfs2_xattr_set(struct inode *, int, const char *, const void *,
extern int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh);
extern struct xattr_handler *ocfs2_xattr_handlers[];

+static inline u16 ocfs2_xattr_buckets_per_cluster(struct ocfs2_super *osb)
+{
+ return (1 << osb->s_clustersize_bits) / OCFS2_XATTR_BUCKET_SIZE;
+}
+
+static inline u16 ocfs2_blocks_per_xattr_bucket(struct super_block *sb)
+{
+ return OCFS2_XATTR_BUCKET_SIZE / (1 << sb->s_blocksize_bits);
+}
#endif /* OCFS2_XATTR_H */
--
1.5.4.5