ocfs2: Improve ocfs2_read_xattr_bucket().

The ocfs2_read_xattr_bucket() function would read an xattr bucket into a
list of buffer heads.  However, we have a nice ocfs2_xattr_bucket
structure.  Let's have it fill that out instead.

In addition, ocfs2_read_xattr_bucket() would initialize buffer heads for
a bucket that's never been on disk before.  That's confusing.  Let's
call that functionality ocfs2_init_xattr_bucket().

The functions ocfs2_cp_xattr_bucket() and ocfs2_half_xattr_bucket() are
updated to use the ocfs2_xattr_bucket structure rather than raw bh
lists.  That way they can use the new read/init calls.  In addition,
they drop the wasted read of an existing target bucket.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 3478ad1..fa13fa4 100644 (file)
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -168,6 +168,48 @@ static void ocfs2_xattr_bucket_relse(struct inode *inode,
        }
 }
 
+/*
+ * A bucket that has never been written to disk doesn't need to be
+ * read.  We just need the buffer_heads.  Don't call this for
+ * buckets that are already on disk.  ocfs2_read_xattr_bucket() initializes
+ * them fully.
+ */
+static int ocfs2_init_xattr_bucket(struct inode *inode,
+                                  struct ocfs2_xattr_bucket *bucket,
+                                  u64 xb_blkno)
+{
+       int i, rc = 0;
+       int blks = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
+
+       for (i = 0; i < blks; i++) {
+               bucket->bu_bhs[i] = sb_getblk(inode->i_sb, xb_blkno + i);
+               if (!bucket->bu_bhs[i]) {
+                       rc = -EIO;
+                       mlog_errno(rc);
+                       break;
+               }
+
+               ocfs2_set_new_buffer_uptodate(inode, bucket->bu_bhs[i]);
+       }
+
+       if (rc)
+               ocfs2_xattr_bucket_relse(inode, bucket);
+       return rc;
+}
+
+/* Read the xattr bucket at xb_blkno */
+static int ocfs2_read_xattr_bucket(struct inode *inode,
+                                  struct ocfs2_xattr_bucket *bucket,
+                                  u64 xb_blkno)
+{
+       int rc, blks = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
+
+       rc = ocfs2_read_blocks(inode, xb_blkno, blks, bucket->bu_bhs, 0);
+       if (rc)
+               ocfs2_xattr_bucket_relse(inode, bucket);
+       return rc;
+}
+
 static inline const char *ocfs2_xattr_prefix(int name_index)
 {
        struct xattr_handler *handler = NULL;
@@ -3097,31 +3139,6 @@ out:
        return ret;
 }
 
-static int ocfs2_read_xattr_bucket(struct inode *inode,
-                                  u64 blkno,
-                                  struct buffer_head **bhs,
-                                  int new)
-{
-       int ret = 0;
-       u16 i, blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
-
-       if (!new)
-               return ocfs2_read_blocks(inode, blkno,
-                                        blk_per_bucket, bhs, 0);
-
-       for (i = 0; i < blk_per_bucket; i++) {
-               bhs[i] = sb_getblk(inode->i_sb, blkno + i);
-               if (bhs[i] == NULL) {
-                       ret = -EIO;
-                       mlog_errno(ret);
-                       break;
-               }
-               ocfs2_set_new_buffer_uptodate(inode, bhs[i]);
-       }
-
-       return ret;
-}
-
 /*
  * Find the suitable pos when we divide a bucket into 2.
  * We have to make sure the xattrs with the same hash value exist
@@ -3184,7 +3201,7 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode,
        int ret, i;
        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_bucket s_bucket, t_bucket;
        struct ocfs2_xattr_header *xh;
        struct ocfs2_xattr_entry *xe;
        int blocksize = inode->i_sb->s_blocksize;
@@ -3192,37 +3209,34 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode,
        mlog(0, "move some of xattrs from bucket %llu to %llu\n",
             (unsigned long long)blk, (unsigned long long)new_blk);
 
-       s_bhs = kcalloc(blk_per_bucket, sizeof(struct buffer_head *), GFP_NOFS);
-       if (!s_bhs)
-               return -ENOMEM;
+       memset(&s_bucket, 0, sizeof(struct ocfs2_xattr_bucket));
+       memset(&t_bucket, 0, sizeof(struct ocfs2_xattr_bucket));
 
-       ret = ocfs2_read_xattr_bucket(inode, blk, s_bhs, 0);
+       ret = ocfs2_read_xattr_bucket(inode, &s_bucket, blk);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
 
-       ret = ocfs2_journal_access(handle, inode, s_bhs[0],
+       ret = ocfs2_journal_access(handle, inode, s_bucket.bu_bhs[0],
                                   OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
 
-       t_bhs = kcalloc(blk_per_bucket, sizeof(struct buffer_head *), GFP_NOFS);
-       if (!t_bhs) {
-               ret = -ENOMEM;
-               goto out;
-       }
-
-       ret = ocfs2_read_xattr_bucket(inode, new_blk, t_bhs, new_bucket_head);
+       /*
+        * Even if !new_bucket_head, we're overwriting t_bucket.  Thus,
+        * there's no need to read it.
+        */
+       ret = ocfs2_init_xattr_bucket(inode, &t_bucket, new_blk);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
 
        for (i = 0; i < blk_per_bucket; i++) {
-               ret = ocfs2_journal_access(handle, inode, t_bhs[i],
+               ret = ocfs2_journal_access(handle, inode, t_bucket.bu_bhs[i],
                                           new_bucket_head ?
                                           OCFS2_JOURNAL_ACCESS_CREATE :
                                           OCFS2_JOURNAL_ACCESS_WRITE);
@@ -3232,7 +3246,7 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode,
                }
        }
 
-       xh = (struct ocfs2_xattr_header *)s_bhs[0]->b_data;
+       xh = bucket_xh(&s_bucket);
        count = le16_to_cpu(xh->xh_count);
        start = ocfs2_xattr_find_divide_pos(xh);
 
@@ -3245,9 +3259,9 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode,
                 * 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);
+                       memset(bucket_block(&t_bucket, i), 0, blocksize);
 
-               xh = (struct ocfs2_xattr_header *)t_bhs[0]->b_data;
+               xh = bucket_xh(&t_bucket);
                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);
@@ -3257,10 +3271,11 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode,
 
        /* 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);
+               memcpy(bucket_block(&t_bucket, i), bucket_block(&s_bucket, i),
+                      blocksize);
 
        /* update the new bucket. */
-       xh = (struct ocfs2_xattr_header *)t_bhs[0]->b_data;
+       xh = bucket_xh(&t_bucket);
 
        /*
         * Calculate the total name/value len and xh_free_start for
@@ -3325,7 +3340,7 @@ set_num_buckets:
                xh->xh_num_buckets = 0;
 
        for (i = 0; i < blk_per_bucket; i++) {
-               ocfs2_journal_dirty(handle, t_bhs[i]);
+               ocfs2_journal_dirty(handle, t_bucket.bu_bhs[i]);
                if (ret)
                        mlog_errno(ret);
        }
@@ -3342,29 +3357,20 @@ set_num_buckets:
        if (start == count)
                goto out;
 
-       xh = (struct ocfs2_xattr_header *)s_bhs[0]->b_data;
+       xh = bucket_xh(&s_bucket);
        memset(&xh->xh_entries[start], 0,
               sizeof(struct ocfs2_xattr_entry) * (count - start));
        xh->xh_count = cpu_to_le16(start);
        xh->xh_free_start = cpu_to_le16(name_offset);
        xh->xh_name_value_len = cpu_to_le16(name_value_len);
 
-       ocfs2_journal_dirty(handle, s_bhs[0]);
+       ocfs2_journal_dirty(handle, s_bucket.bu_bhs[0]);
        if (ret)
                mlog_errno(ret);
 
 out:
-       if (s_bhs) {
-               for (i = 0; i < blk_per_bucket; i++)
-                       brelse(s_bhs[i]);
-       }
-       kfree(s_bhs);
-
-       if (t_bhs) {
-               for (i = 0; i < blk_per_bucket; i++)
-                       brelse(t_bhs[i]);
-       }
-       kfree(t_bhs);
+       ocfs2_xattr_bucket_relse(inode, &s_bucket);
+       ocfs2_xattr_bucket_relse(inode, &t_bucket);
 
        return ret;
 }
@@ -3384,7 +3390,7 @@ static int ocfs2_cp_xattr_bucket(struct inode *inode,
        int ret, i;
        int blk_per_bucket = ocfs2_blocks_per_xattr_bucket(inode->i_sb);
        int blocksize = inode->i_sb->s_blocksize;
-       struct buffer_head **s_bhs, **t_bhs = NULL;
+       struct ocfs2_xattr_bucket s_bucket, t_bucket;
 
        BUG_ON(s_blkno == t_blkno);
 
@@ -3392,28 +3398,23 @@ static int ocfs2_cp_xattr_bucket(struct inode *inode,
             (unsigned long long)s_blkno, (unsigned long long)t_blkno,
             t_is_new);
 
-       s_bhs = kzalloc(sizeof(struct buffer_head *) * blk_per_bucket,
-                       GFP_NOFS);
-       if (!s_bhs)
-               return -ENOMEM;
+       memset(&s_bucket, 0, sizeof(struct ocfs2_xattr_bucket));
+       memset(&t_bucket, 0, sizeof(struct ocfs2_xattr_bucket));
 
-       ret = ocfs2_read_xattr_bucket(inode, s_blkno, s_bhs, 0);
+       ret = ocfs2_read_xattr_bucket(inode, &s_bucket, s_blkno);
        if (ret)
                goto out;
 
-       t_bhs = kzalloc(sizeof(struct buffer_head *) * blk_per_bucket,
-                       GFP_NOFS);
-       if (!t_bhs) {
-               ret = -ENOMEM;
-               goto out;
-       }
-
-       ret = ocfs2_read_xattr_bucket(inode, t_blkno, t_bhs, t_is_new);
+       /*
+        * Even if !t_is_new, we're overwriting t_bucket.  Thus,
+        * there's no need to read it.
+        */
+       ret = ocfs2_init_xattr_bucket(inode, &t_bucket, t_blkno);
        if (ret)
                goto out;
 
        for (i = 0; i < blk_per_bucket; i++) {
-               ret = ocfs2_journal_access(handle, inode, t_bhs[i],
+               ret = ocfs2_journal_access(handle, inode, t_bucket.bu_bhs[i],
                                           t_is_new ?
                                           OCFS2_JOURNAL_ACCESS_CREATE :
                                           OCFS2_JOURNAL_ACCESS_WRITE);
@@ -3422,22 +3423,14 @@ static int ocfs2_cp_xattr_bucket(struct inode *inode,
        }
 
        for (i = 0; i < blk_per_bucket; i++) {
-               memcpy(t_bhs[i]->b_data, s_bhs[i]->b_data, blocksize);
-               ocfs2_journal_dirty(handle, t_bhs[i]);
+               memcpy(bucket_block(&t_bucket, i), bucket_block(&s_bucket, i),
+                      blocksize);
+               ocfs2_journal_dirty(handle, t_bucket.bu_bhs[i]);
        }
 
 out:
-       if (s_bhs) {
-               for (i = 0; i < blk_per_bucket; i++)
-                       brelse(s_bhs[i]);
-       }
-       kfree(s_bhs);
-
-       if (t_bhs) {
-               for (i = 0; i < blk_per_bucket; i++)
-                       brelse(t_bhs[i]);
-       }
-       kfree(t_bhs);
+       ocfs2_xattr_bucket_relse(inode, &s_bucket);
+       ocfs2_xattr_bucket_relse(inode, &t_bucket);
 
        return ret;
 }