ocfs2: Allocate discontiguous block groups.

If we cannot get a contiguous region for a block group, allocate a
discontiguous one when the filesystem supports it.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Tao Ma <tao.ma@oracle.com>

3 files changed, 291 insertions, 40 deletions

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index a388528f485c..d389f2714c96 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -491,6 +491,13 @@ static inline int ocfs2_supports_indexed_dirs(struct ocfs2_super *osb)
         return 0;
 }
 
+static inline int ocfs2_supports_discontig_bh(struct ocfs2_super *osb)
+{
+        if (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG)
+                return 1;
+        return 0;
+}
+
 static inline unsigned int ocfs2_link_max(struct ocfs2_super *osb)
 {
         if (ocfs2_supports_indexed_dirs(osb))
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 448aa8d11a97..888ba4ec42c6 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -1278,6 +1278,16 @@ static inline u16 ocfs2_extent_recs_per_eb(struct super_block *sb)
         return size / sizeof(struct ocfs2_extent_rec);
 }
 
+static inline u16 ocfs2_extent_recs_per_gd(struct super_block *sb)
+{
+        int size;
+
+        size = sb->s_blocksize -
+                offsetof(struct ocfs2_group_desc, bg_list.l_recs);
+
+        return size / sizeof(struct ocfs2_extent_rec);
+}
+
 static inline int ocfs2_dx_entries_per_leaf(struct super_block *sb)
 {
         int size;
@@ -1430,6 +1440,16 @@ static inline int ocfs2_extent_recs_per_eb(int blocksize)
         return size / sizeof(struct ocfs2_extent_rec);
 }
 
+static inline int ocfs2_extent_recs_per_gd(int blocksize)
+{
+        int size;
+
+        size = blocksize -
+                offsetof(struct ocfs2_group_desc, bg_list.l_recs);
+
+        return size / sizeof(struct ocfs2_extent_rec);
+}
+
 static inline int ocfs2_local_alloc_size(int blocksize)
 {
         int size;
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 1070f79fa068..2f753954a7a8 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -60,6 +60,7 @@ static int ocfs2_block_group_fill(handle_t *handle,
                                   struct inode *alloc_inode,
                                   struct buffer_head *bg_bh,
                                   u64 group_blkno,
+                                  unsigned int group_clusters,
                                   u16 my_chain,
                                   struct ocfs2_chain_list *cl);
 static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
@@ -326,14 +327,36 @@ out:
         return rc;
 }
 
+static void ocfs2_bg_discontig_add_extent(struct ocfs2_super *osb,
+                                          struct ocfs2_group_desc *bg,
+                                          struct ocfs2_chain_list *cl,
+                                          u64 p_blkno, u32 clusters)
+{
+        struct ocfs2_extent_list *el = &bg->bg_list;
+        struct ocfs2_extent_rec *rec;
+
+        BUG_ON(!ocfs2_supports_discontig_bh(osb));
+        if (!el->l_next_free_rec)
+                el->l_count = cpu_to_le16(ocfs2_extent_recs_per_gd(osb->sb));
+        rec = &el->l_recs[le16_to_cpu(el->l_next_free_rec)];
+        rec->e_blkno = p_blkno;
+        rec->e_cpos = cpu_to_le32(le16_to_cpu(bg->bg_bits) /
+                                  le16_to_cpu(cl->cl_bpc));
+        rec->e_leaf_clusters = cpu_to_le32(clusters);
+        le16_add_cpu(&bg->bg_bits, clusters * le16_to_cpu(cl->cl_bpc));
+        le16_add_cpu(&el->l_next_free_rec, 1);
+}
+
 static int ocfs2_block_group_fill(handle_t *handle,
                                   struct inode *alloc_inode,
                                   struct buffer_head *bg_bh,
                                   u64 group_blkno,
+                                  unsigned int group_clusters,
                                   u16 my_chain,
                                   struct ocfs2_chain_list *cl)
 {
         int status = 0;
+        struct ocfs2_super *osb = OCFS2_SB(alloc_inode->i_sb);
         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
         struct super_block * sb = alloc_inode->i_sb;
 
@@ -361,11 +384,16 @@ static int ocfs2_block_group_fill(handle_t *handle,
         strcpy(bg->bg_signature, OCFS2_GROUP_DESC_SIGNATURE);
         bg->bg_generation = cpu_to_le32(OCFS2_SB(sb)->fs_generation);
         bg->bg_size = cpu_to_le16(ocfs2_group_bitmap_size(sb, 1));
-        bg->bg_bits = cpu_to_le16(ocfs2_bits_per_group(cl));
         bg->bg_chain = cpu_to_le16(my_chain);
         bg->bg_next_group = cl->cl_recs[my_chain].c_blkno;
         bg->bg_parent_dinode = cpu_to_le64(OCFS2_I(alloc_inode)->ip_blkno);
         bg->bg_blkno = cpu_to_le64(group_blkno);
+        if (group_clusters == le16_to_cpu(cl->cl_cpg))
+                bg->bg_bits = cpu_to_le16(ocfs2_bits_per_group(cl));
+        else
+                ocfs2_bg_discontig_add_extent(osb, bg, cl, bg->bg_blkno,
+                                              group_clusters);
+
         /* set the 1st bit in the bitmap to account for the descriptor block */
         ocfs2_set_bit(0, (unsigned long *)bg->bg_bitmap);
         bg->bg_free_bits_count = cpu_to_le16(le16_to_cpu(bg->bg_bits) - 1);
@@ -396,6 +424,218 @@ static inline u16 ocfs2_find_smallest_chain(struct ocfs2_chain_list *cl)
         return best;
 }
 
+static struct buffer_head *
+ocfs2_block_group_alloc_contig(struct ocfs2_super *osb, handle_t *handle,
+                               struct inode *alloc_inode,
+                               struct ocfs2_alloc_context *ac,
+                               struct ocfs2_chain_list *cl)
+{
+        int status;
+        u32 bit_off, num_bits;
+        u64 bg_blkno;
+        struct buffer_head *bg_bh;
+        unsigned int alloc_rec = ocfs2_find_smallest_chain(cl);
+
+        status = ocfs2_claim_clusters(osb, handle, ac,
+                                      le16_to_cpu(cl->cl_cpg), &bit_off,
+                                      &num_bits);
+        if (status < 0) {
+                if (status != -ENOSPC)
+                        mlog_errno(status);
+                goto bail;
+        }
+
+        /* setup the group */
+        bg_blkno = ocfs2_clusters_to_blocks(osb->sb, bit_off);
+        mlog(0, "new descriptor, record %u, at block %llu\n",
+             alloc_rec, (unsigned long long)bg_blkno);
+
+        bg_bh = sb_getblk(osb->sb, bg_blkno);
+        if (!bg_bh) {
+                status = -EIO;
+                mlog_errno(status);
+                goto bail;
+        }
+        ocfs2_set_new_buffer_uptodate(INODE_CACHE(alloc_inode), bg_bh);
+
+        status = ocfs2_block_group_fill(handle, alloc_inode, bg_bh,
+                                        bg_blkno, num_bits, alloc_rec, cl);
+        if (status < 0) {
+                brelse(bg_bh);
+                mlog_errno(status);
+        }
+
+bail:
+        return status ? ERR_PTR(status) : bg_bh;
+}
+
+static int ocfs2_block_group_claim_bits(struct ocfs2_super *osb,
+                                        handle_t *handle,
+                                        struct ocfs2_alloc_context *ac,
+                                        unsigned int min_bits,
+                                        u32 *bit_off, u32 *num_bits)
+{
+        int status;
+
+        while (min_bits) {
+                status = ocfs2_claim_clusters(osb, handle, ac, min_bits,
+                                              bit_off, num_bits);
+                if (status != -ENOSPC)
+                        break;
+
+                min_bits >>= 1;
+        }
+
+        return status;
+}
+
+static int ocfs2_block_group_grow_discontig(handle_t *handle,
+                                            struct inode *alloc_inode,
+                                            struct buffer_head *bg_bh,
+                                            struct ocfs2_alloc_context *ac,
+                                            struct ocfs2_chain_list *cl,
+                                            unsigned int min_bits)
+{
+        int status;
+        struct ocfs2_super *osb = OCFS2_SB(alloc_inode->i_sb);
+        struct ocfs2_group_desc *bg =
+                (struct ocfs2_group_desc *)bg_bh->b_data;
+        unsigned int needed =
+                ocfs2_bits_per_group(cl) - le16_to_cpu(bg->bg_bits);
+        u32 p_cpos, clusters;
+        u64 p_blkno;
+        struct ocfs2_extent_list *el = &bg->bg_list;
+
+        status = ocfs2_journal_access_gd(handle,
+                                         INODE_CACHE(alloc_inode),
+                                         bg_bh,
+                                         OCFS2_JOURNAL_ACCESS_CREATE);
+        if (status < 0) {
+                mlog_errno(status);
+                goto bail;
+        }
+
+        while ((needed > 0) && (le16_to_cpu(el->l_next_free_rec) <
+                                le16_to_cpu(el->l_count))) {
+                status = ocfs2_extend_trans(handle, OCFS2_SUBALLOC_ALLOC);
+                if (status) {
+                        mlog_errno(status);
+                        goto bail;
+                }
+
+                if (min_bits > needed)
+                        min_bits = needed;
+                status = ocfs2_block_group_claim_bits(osb, handle, ac,
+                                                      min_bits, &p_cpos,
+                                                      &clusters);
+                if (status < 0) {
+                        if (status != -ENOSPC)
+                                mlog_errno(status);
+                        goto bail;
+                }
+                p_blkno = ocfs2_clusters_to_blocks(osb->sb, p_cpos);
+                ocfs2_bg_discontig_add_extent(osb, bg, cl, p_blkno,
+                                              clusters);
+
+                min_bits = clusters;
+                needed = ocfs2_bits_per_group(cl) - le16_to_cpu(bg->bg_bits);
+        }
+
+        if (needed > 0) {
+        }
+
+        ocfs2_journal_dirty(handle, bg_bh);
+
+bail:
+        return status;
+}
+
+static void ocfs2_bg_alloc_cleanup(struct inode *alloc_inode,
+                                   struct buffer_head *bg_bh,
+                                   struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+        int i;
+        struct ocfs2_group_desc *bg;
+        struct ocfs2_extent_list *el;
+        struct ocfs2_extent_rec *rec;
+
+        if (!bg_bh)
+                return;
+
+        bg = (struct ocfs2_group_desc *)bg_bh->b_data;
+        el = &bg->bg_list;
+        for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+                rec = &el->l_recs[i];
+                ocfs2_cache_cluster_dealloc(dealloc,
+                                            le64_to_cpu(rec->e_blkno),
+                                            le32_to_cpu(rec->e_leaf_clusters));
+        }
+
+        ocfs2_remove_from_cache(INODE_CACHE(alloc_inode), bg_bh);
+        brelse(bg_bh);
+}
+
+static struct buffer_head *
+ocfs2_block_group_alloc_discontig(handle_t *handle,
+                                  struct inode *alloc_inode,
+                                  struct ocfs2_alloc_context *ac,
+                                  struct ocfs2_chain_list *cl,
+                                  struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+        int status;
+        u32 bit_off, num_bits;
+        u64 bg_blkno;
+        unsigned int min_bits = le16_to_cpu(cl->cl_cpg) >> 1;
+        struct buffer_head *bg_bh = NULL;
+        unsigned int alloc_rec = ocfs2_find_smallest_chain(cl);
+        struct ocfs2_super *osb = OCFS2_SB(alloc_inode->i_sb);
+
+        if (!ocfs2_supports_discontig_bh(osb)) {
+                status = -ENOSPC;
+                goto bail;
+        }
+
+        /* Claim the first region */
+        status = ocfs2_block_group_claim_bits(osb, handle, ac, min_bits,
+                                              &bit_off, &num_bits);
+        if (status < 0) {
+                if (status != -ENOSPC)
+                        mlog_errno(status);
+                goto bail;
+        }
+        min_bits = num_bits;
+
+        /* setup the group */
+        bg_blkno = ocfs2_clusters_to_blocks(osb->sb, bit_off);
+        mlog(0, "new descriptor, record %u, at block %llu\n",
+             alloc_rec, (unsigned long long)bg_blkno);
+
+        bg_bh = sb_getblk(osb->sb, bg_blkno);
+        if (!bg_bh) {
+                status = -EIO;
+                mlog_errno(status);
+                goto bail;
+        }
+        ocfs2_set_new_buffer_uptodate(INODE_CACHE(alloc_inode), bg_bh);
+
+        status = ocfs2_block_group_fill(handle, alloc_inode, bg_bh,
+                                        bg_blkno, num_bits, alloc_rec, cl);
+        if (status < 0) {
+                mlog_errno(status);
+                goto bail;
+        }
+
+        status = ocfs2_block_group_grow_discontig(handle, alloc_inode,
+                                                  bg_bh, ac, cl, min_bits);
+        if (status)
+                mlog_errno(status);
+
+bail:
+        if (status)
+                ocfs2_bg_alloc_cleanup(alloc_inode, bg_bh, dealloc);
+        return status ? ERR_PTR(status) : bg_bh;
+}
+
 /*
  * We expect the block group allocator to already be locked.
  */
@@ -411,16 +651,17 @@ static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
         struct ocfs2_chain_list *cl;
         struct ocfs2_alloc_context *ac = NULL;
         handle_t *handle = NULL;
-        u32 bit_off, num_bits;
-        u16 alloc_rec;
         u64 bg_blkno;
         struct buffer_head *bg_bh = NULL;
         struct ocfs2_group_desc *bg;
+        struct ocfs2_cached_dealloc_ctxt dealloc;
 
         BUG_ON(ocfs2_is_cluster_bitmap(alloc_inode));
 
         mlog_entry_void();
 
+        ocfs2_init_dealloc_ctxt(&dealloc);
+
         cl = &fe->id2.i_chain;
         status = ocfs2_reserve_clusters_with_limit(osb,
                                                    le16_to_cpu(cl->cl_cpg),
@@ -446,44 +687,21 @@ static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
                      (unsigned long long)*last_alloc_group);
                 ac->ac_last_group = *last_alloc_group;
         }
-        status = ocfs2_claim_clusters(osb,
-                                      handle,
-                                      ac,
-                                      le16_to_cpu(cl->cl_cpg),
-                                      &bit_off,
-                                      &num_bits);
-        if (status < 0) {
+
+        bg_bh = ocfs2_block_group_alloc_contig(osb, handle, alloc_inode,
+                                               ac, cl);
+        if (IS_ERR(bg_bh) && (PTR_ERR(bg_bh) == -ENOSPC))
+                bg_bh = ocfs2_block_group_alloc_discontig(handle,
+                                                          alloc_inode,
+                                                          ac, cl,
+                                                          &dealloc);
+        if (IS_ERR(bg_bh)) {
+                status = PTR_ERR(bg_bh);
+                bg_bh = NULL;
                 if (status != -ENOSPC)
                         mlog_errno(status);
                 goto bail;
         }
-
-        alloc_rec = ocfs2_find_smallest_chain(cl);
-
-        /* setup the group */
-        bg_blkno = ocfs2_clusters_to_blocks(osb->sb, bit_off);
-        mlog(0, "new descriptor, record %u, at block %llu\n",
-             alloc_rec, (unsigned long long)bg_blkno);
-
-        bg_bh = sb_getblk(osb->sb, bg_blkno);
-        if (!bg_bh) {
-                status = -EIO;
-                mlog_errno(status);
-                goto bail;
-        }
-        ocfs2_set_new_buffer_uptodate(INODE_CACHE(alloc_inode), bg_bh);
-
-        status = ocfs2_block_group_fill(handle,
-                                        alloc_inode,
-                                        bg_bh,
-                                        bg_blkno,
-                                        alloc_rec,
-                                        cl);
-        if (status < 0) {
-                mlog_errno(status);
-                goto bail;
-        }
-
         bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 
         status = ocfs2_journal_access_di(handle, INODE_CACHE(alloc_inode),
@@ -493,10 +711,11 @@ static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
                 goto bail;
         }
 
-        le32_add_cpu(&cl->cl_recs[alloc_rec].c_free,
+        le32_add_cpu(&cl->cl_recs[bg->bg_chain].c_free,
                      le16_to_cpu(bg->bg_free_bits_count));
-        le32_add_cpu(&cl->cl_recs[alloc_rec].c_total, le16_to_cpu(bg->bg_bits));
-        cl->cl_recs[alloc_rec].c_blkno  = cpu_to_le64(bg_blkno);
+        le32_add_cpu(&cl->cl_recs[bg->bg_chain].c_total,
+                     le16_to_cpu(bg->bg_bits));
+        cl->cl_recs[bg->bg_chain].c_blkno  = cpu_to_le64(bg_blkno);
         if (le16_to_cpu(cl->cl_next_free_rec) < le16_to_cpu(cl->cl_count))
                 le16_add_cpu(&cl->cl_next_free_rec, 1);
 
@@ -525,6 +744,11 @@ bail:
         if (handle)
                 ocfs2_commit_trans(osb, handle);
 
+        if (ocfs2_dealloc_has_cluster(&dealloc)) {
+                ocfs2_schedule_truncate_log_flush(osb, 1);
+                ocfs2_run_deallocs(osb, &dealloc);
+        }
+
         if (ac)
                 ocfs2_free_alloc_context(ac);