ocfs2: allocation hints
[linux-2.6.git] / fs / ocfs2 / suballoc.c
index 7ac68cac041d9f7c0765a819cbec49c8b57a3b12..9d91e66f51a9fa4606a6f864e2bc7531e10c1a75 100644 (file)
@@ -70,12 +70,6 @@ static int ocfs2_block_group_search(struct inode *inode,
                                    struct buffer_head *group_bh,
                                    u32 bits_wanted, u32 min_bits,
                                    u16 *bit_off, u16 *bits_found);
-static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
-                             u32 bits_wanted,
-                             u32 min_bits,
-                             u16 *bit_off,
-                             unsigned int *num_bits,
-                             u64 *bg_blkno);
 static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
                                     struct ocfs2_alloc_context *ac,
                                     u32 bits_wanted,
@@ -1030,12 +1024,103 @@ static int ocfs2_block_group_search(struct inode *inode,
        return ret;
 }
 
+static int ocfs2_alloc_dinode_update_counts(struct inode *inode,
+                                      struct ocfs2_journal_handle *handle,
+                                      struct buffer_head *di_bh,
+                                      u32 num_bits,
+                                      u16 chain)
+{
+       int ret;
+       u32 tmp_used;
+       struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;
+       struct ocfs2_chain_list *cl = (struct ocfs2_chain_list *) &di->id2.i_chain;
+
+       ret = ocfs2_journal_access(handle, inode, di_bh,
+                                  OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret < 0) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       tmp_used = le32_to_cpu(di->id1.bitmap1.i_used);
+       di->id1.bitmap1.i_used = cpu_to_le32(num_bits + tmp_used);
+       le32_add_cpu(&cl->cl_recs[chain].c_free, -num_bits);
+
+       ret = ocfs2_journal_dirty(handle, di_bh);
+       if (ret < 0)
+               mlog_errno(ret);
+
+out:
+       return ret;
+}
+
+static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
+                                 u32 bits_wanted,
+                                 u32 min_bits,
+                                 u16 *bit_off,
+                                 unsigned int *num_bits,
+                                 u64 gd_blkno,
+                                 u16 *bits_left)
+{
+       int ret;
+       u16 found;
+       struct buffer_head *group_bh = NULL;
+       struct ocfs2_group_desc *gd;
+       struct inode *alloc_inode = ac->ac_inode;
+       struct ocfs2_journal_handle *handle = ac->ac_handle;
+
+       ret = ocfs2_read_block(OCFS2_SB(alloc_inode->i_sb), gd_blkno,
+                              &group_bh, OCFS2_BH_CACHED, alloc_inode);
+       if (ret < 0) {
+               mlog_errno(ret);
+               return ret;
+       }
+
+       gd = (struct ocfs2_group_desc *) group_bh->b_data;
+       if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
+               OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, gd);
+               ret = -EIO;
+               goto out;
+       }
+
+       ret = ac->ac_group_search(alloc_inode, group_bh, bits_wanted, min_bits,
+                                 bit_off, &found);
+       if (ret < 0) {
+               if (ret != -ENOSPC)
+                       mlog_errno(ret);
+               goto out;
+       }
+
+       *num_bits = found;
+
+       ret = ocfs2_alloc_dinode_update_counts(alloc_inode, handle, ac->ac_bh,
+                                              *num_bits,
+                                              le16_to_cpu(gd->bg_chain));
+       if (ret < 0) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_block_group_set_bits(handle, alloc_inode, gd, group_bh,
+                                        *bit_off, *num_bits);
+       if (ret < 0)
+               mlog_errno(ret);
+
+       *bits_left = le16_to_cpu(gd->bg_free_bits_count);
+
+out:
+       brelse(group_bh);
+
+       return ret;
+}
+
 static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
                              u32 bits_wanted,
                              u32 min_bits,
                              u16 *bit_off,
                              unsigned int *num_bits,
-                             u64 *bg_blkno)
+                             u64 *bg_blkno,
+                             u16 *bits_left)
 {
        int status;
        u16 chain, tmp_bits;
@@ -1173,6 +1258,7 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
             (unsigned long long)fe->i_blkno);
 
        *bg_blkno = le64_to_cpu(bg->bg_blkno);
+       *bits_left = le16_to_cpu(bg->bg_free_bits_count);
 bail:
        if (group_bh)
                brelse(group_bh);
@@ -1194,6 +1280,8 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
 {
        int status;
        u16 victim, i;
+       u16 bits_left = 0;
+       u64 hint_blkno = ac->ac_last_group;
        struct ocfs2_chain_list *cl;
        struct ocfs2_dinode *fe;
 
@@ -1220,6 +1308,28 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
                goto bail;
        }
 
+       if (hint_blkno) {
+               /* Attempt to short-circuit the usual search mechanism
+                * by jumping straight to the most recently used
+                * allocation group. This helps us mantain some
+                * contiguousness across allocations. */
+               status = ocfs2_search_one_group(ac, bits_wanted, min_bits,
+                                               bit_off, num_bits,
+                                               hint_blkno, &bits_left);
+               if (!status) {
+                       /* Be careful to update *bg_blkno here as the
+                        * caller is expecting it to be filled in, and
+                        * ocfs2_search_one_group() won't do that for
+                        * us. */
+                       *bg_blkno = hint_blkno;
+                       goto set_hint;
+               }
+               if (status < 0 && status != -ENOSPC) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+       }
+
        cl = (struct ocfs2_chain_list *) &fe->id2.i_chain;
 
        victim = ocfs2_find_victim_chain(cl);
@@ -1227,9 +1337,9 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
        ac->ac_allow_chain_relink = 1;
 
        status = ocfs2_search_chain(ac, bits_wanted, min_bits, bit_off,
-                                   num_bits, bg_blkno);
+                                   num_bits, bg_blkno, &bits_left);
        if (!status)
-               goto bail;
+               goto set_hint;
        if (status < 0 && status != -ENOSPC) {
                mlog_errno(status);
                goto bail;
@@ -1251,8 +1361,8 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
 
                ac->ac_chain = i;
                status = ocfs2_search_chain(ac, bits_wanted, min_bits,
-                                           bit_off, num_bits,
-                                           bg_blkno);
+                                           bit_off, num_bits, bg_blkno,
+                                           &bits_left);
                if (!status)
                        break;
                if (status < 0 && status != -ENOSPC) {
@@ -1260,8 +1370,19 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
                        goto bail;
                }
        }
-bail:
 
+set_hint:
+       if (status != -ENOSPC) {
+               /* If the next search of this group is not likely to
+                * yield a suitable extent, then we reset the last
+                * group hint so as to not waste a disk read */
+               if (bits_left < min_bits)
+                       ac->ac_last_group = 0;
+               else
+                       ac->ac_last_group = *bg_blkno;
+       }
+
+bail:
        mlog_exit(status);
        return status;
 }
@@ -1415,7 +1536,7 @@ int ocfs2_claim_clusters(struct ocfs2_super *osb,
 {
        int status;
        unsigned int bits_wanted = ac->ac_bits_wanted - ac->ac_bits_given;
-       u64 bg_blkno;
+       u64 bg_blkno = 0;
        u16 bg_bit_off;
 
        mlog_entry_void();