ocfs2: Pass suballocation results back via a structure.

We're going to be adding more info to a suballocator allocation.  Rather
than growing every function in the chain, let's pass a result structure
around.

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

2 files changed, 72 insertions, 98 deletions

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 2f753954a7a8..3d823cffc620 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -53,6 +53,12 @@
 
 #define OCFS2_MAX_TO_STEAL              1024
 
+struct ocfs2_suballoc_result {
+        u64             sr_bg_blkno;    /* The bg we allocated from */
+        unsigned int    sr_bit_offset;  /* The bit in the bg */
+        unsigned int    sr_bits;        /* How many bits we claimed */
+};
+
 static inline void ocfs2_debug_bg(struct ocfs2_group_desc *bg);
 static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe);
 static inline u16 ocfs2_find_victim_chain(struct ocfs2_chain_list *cl);
@@ -74,20 +80,18 @@ static int ocfs2_cluster_group_search(struct inode *inode,
                                       struct buffer_head *group_bh,
                                       u32 bits_wanted, u32 min_bits,
                                       u64 max_block,
-                                      u16 *bit_off, u16 *bits_found);
+                                      struct ocfs2_suballoc_result *res);
 static int ocfs2_block_group_search(struct inode *inode,
                                     struct buffer_head *group_bh,
                                     u32 bits_wanted, u32 min_bits,
                                     u64 max_block,
-                                    u16 *bit_off, u16 *bits_found);
+                                    struct ocfs2_suballoc_result *res);
 static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
                                      struct ocfs2_alloc_context *ac,
                                      handle_t *handle,
                                      u32 bits_wanted,
                                      u32 min_bits,
-                                     u16 *bit_off,
-                                     unsigned int *num_bits,
-                                     u64 *bg_blkno);
+                                     struct ocfs2_suballoc_result *res);
 static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
                                          int nr);
 static inline int ocfs2_block_group_set_bits(handle_t *handle,
@@ -1248,8 +1252,7 @@ static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
                                              struct buffer_head *bg_bh,
                                              unsigned int bits_wanted,
                                              unsigned int total_bits,
-                                             u16 *bit_off,
-                                             u16 *bits_found)
+                                             struct ocfs2_suballoc_result *res)
 {
         void *bitmap;
         u16 best_offset, best_size;
@@ -1293,14 +1296,9 @@ static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
                 }
         }
 
-        /* XXX: I think the first clause is equivalent to the second
-         *      - jlbec */
-        if (found == bits_wanted) {
-                *bit_off = start - found;
-                *bits_found = found;
-        } else if (best_size) {
-                *bit_off = best_offset;
-                *bits_found = best_size;
+        if (best_size) {
+                res->sr_bit_offset = best_offset;
+                res->sr_bits = best_size;
         } else {
                 status = -ENOSPC;
                 /* No error log here -- see the comment above
@@ -1456,14 +1454,13 @@ static int ocfs2_cluster_group_search(struct inode *inode,
                                       struct buffer_head *group_bh,
                                       u32 bits_wanted, u32 min_bits,
                                       u64 max_block,
-                                      u16 *bit_off, u16 *bits_found)
+                                      struct ocfs2_suballoc_result *res)
 {
         int search = -ENOSPC;
         int ret;
         u64 blkoff;
         struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *) group_bh->b_data;
         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-        u16 tmp_off, tmp_found;
         unsigned int max_bits, gd_cluster_off;
 
         BUG_ON(!ocfs2_is_cluster_bitmap(inode));
@@ -1490,15 +1487,15 @@ static int ocfs2_cluster_group_search(struct inode *inode,
 
                 ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),
                                                         group_bh, bits_wanted,
-                                                        max_bits,
-                                                        &tmp_off, &tmp_found);
+                                                        max_bits, res);
                 if (ret)
                         return ret;
 
                 if (max_block) {
                         blkoff = ocfs2_clusters_to_blocks(inode->i_sb,
                                                           gd_cluster_off +
-                                                          tmp_off + tmp_found);
+                                                          res->sr_bit_offset +
+                                                          res->sr_bits);
                         mlog(0, "Checking %llu against %llu\n",
                              (unsigned long long)blkoff,
                              (unsigned long long)max_block);
@@ -1510,16 +1507,14 @@ static int ocfs2_cluster_group_search(struct inode *inode,
                  * return success, but we still want to return
                  * -ENOSPC unless it found the minimum number
                  * of bits. */
-                if (min_bits <= tmp_found) {
-                        *bit_off = tmp_off;
-                        *bits_found = tmp_found;
+                if (min_bits <= res->sr_bits)
                         search = 0; /* success */
-                } else if (tmp_found) {
+                else if (res->sr_bits) {
                         /*
                          * Don't show bits which we'll be returning
                          * for allocation to the local alloc bitmap.
                          */
-                        ocfs2_local_alloc_seen_free_bits(osb, tmp_found);
+                        ocfs2_local_alloc_seen_free_bits(osb, res->sr_bits);
                 }
         }
 
@@ -1530,7 +1525,7 @@ static int ocfs2_block_group_search(struct inode *inode,
                                     struct buffer_head *group_bh,
                                     u32 bits_wanted, u32 min_bits,
                                     u64 max_block,
-                                    u16 *bit_off, u16 *bits_found)
+                                    struct ocfs2_suballoc_result *res)
 {
         int ret = -ENOSPC;
         u64 blkoff;
@@ -1543,10 +1538,10 @@ static int ocfs2_block_group_search(struct inode *inode,
                 ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),
                                                         group_bh, bits_wanted,
                                                         le16_to_cpu(bg->bg_bits),
-                                                        bit_off, bits_found);
+                                                        res);
                 if (!ret && max_block) {
-                        blkoff = le64_to_cpu(bg->bg_blkno) + *bit_off +
-                                *bits_found;
+                        blkoff = le64_to_cpu(bg->bg_blkno) +
+                                res->sr_bit_offset + res->sr_bits;
                         mlog(0, "Checking %llu against %llu\n",
                              (unsigned long long)blkoff,
                              (unsigned long long)max_block);
@@ -1589,20 +1584,17 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
                                   handle_t *handle,
                                   u32 bits_wanted,
                                   u32 min_bits,
-                                  u16 *bit_off,
-                                  unsigned int *num_bits,
-                                  u64 gd_blkno,
+                                  struct ocfs2_suballoc_result *res,
                                   u16 *bits_left)
 {
         int ret;
-        u16 found;
         struct buffer_head *group_bh = NULL;
         struct ocfs2_group_desc *gd;
         struct ocfs2_dinode *di = (struct ocfs2_dinode *)ac->ac_bh->b_data;
         struct inode *alloc_inode = ac->ac_inode;
 
-        ret = ocfs2_read_group_descriptor(alloc_inode, di, gd_blkno,
-                                          &group_bh);
+        ret = ocfs2_read_group_descriptor(alloc_inode, di,
+                                          res->sr_bg_blkno, &group_bh);
         if (ret < 0) {
                 mlog_errno(ret);
                 return ret;
@@ -1610,17 +1602,15 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
 
         gd = (struct ocfs2_group_desc *) group_bh->b_data;
         ret = ac->ac_group_search(alloc_inode, group_bh, bits_wanted, min_bits,
-                                  ac->ac_max_block, bit_off, &found);
+                                  ac->ac_max_block, res);
         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,
+                                               res->sr_bits,
                                                le16_to_cpu(gd->bg_chain));
         if (ret < 0) {
                 mlog_errno(ret);
@@ -1628,7 +1618,7 @@ static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
         }
 
         ret = ocfs2_block_group_set_bits(handle, alloc_inode, gd, group_bh,
-                                         *bit_off, *num_bits);
+                                         res->sr_bit_offset, res->sr_bits);
         if (ret < 0)
                 mlog_errno(ret);
 
@@ -1644,13 +1634,11 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
                               handle_t *handle,
                               u32 bits_wanted,
                               u32 min_bits,
-                              u16 *bit_off,
-                              unsigned int *num_bits,
-                              u64 *bg_blkno,
+                              struct ocfs2_suballoc_result *res,
                               u16 *bits_left)
 {
         int status;
-        u16 chain, tmp_bits;
+        u16 chain;
         u32 tmp_used;
         u64 next_group;
         struct inode *alloc_inode = ac->ac_inode;
@@ -1679,8 +1667,8 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
          * the 1st group with any empty bits. */
         while ((status = ac->ac_group_search(alloc_inode, group_bh,
                                              bits_wanted, min_bits,
-                                             ac->ac_max_block, bit_off,
-                                             &tmp_bits)) == -ENOSPC) {
+                                             ac->ac_max_block,
+                                             res)) == -ENOSPC) {
                 if (!bg->bg_next_group)
                         break;
 
@@ -1705,11 +1693,11 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
         }
 
         mlog(0, "alloc succeeds: we give %u bits from block group %llu\n",
-             tmp_bits, (unsigned long long)le64_to_cpu(bg->bg_blkno));
+             res->sr_bits, (unsigned long long)le64_to_cpu(bg->bg_blkno));
 
-        *num_bits = tmp_bits;
+        res->sr_bg_blkno = le64_to_cpu(bg->bg_blkno);
 
-        BUG_ON(*num_bits == 0);
+        BUG_ON(res->sr_bits == 0);
 
         /*
          * Keep track of previous block descriptor read. When
@@ -1726,7 +1714,7 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
          */
         if (ac->ac_allow_chain_relink &&
             (prev_group_bh) &&
-            (ocfs2_block_group_reasonably_empty(bg, *num_bits))) {
+            (ocfs2_block_group_reasonably_empty(bg, res->sr_bits))) {
                 status = ocfs2_relink_block_group(handle, alloc_inode,
                                                   ac->ac_bh, group_bh,
                                                   prev_group_bh, chain);
@@ -1748,25 +1736,24 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
         }
 
         tmp_used = le32_to_cpu(fe->id1.bitmap1.i_used);
-        fe->id1.bitmap1.i_used = cpu_to_le32(*num_bits + tmp_used);
-        le32_add_cpu(&cl->cl_recs[chain].c_free, -(*num_bits));
+        fe->id1.bitmap1.i_used = cpu_to_le32(res->sr_bits + tmp_used);
+        le32_add_cpu(&cl->cl_recs[chain].c_free, -res->sr_bits);
         ocfs2_journal_dirty(handle, ac->ac_bh);
 
         status = ocfs2_block_group_set_bits(handle,
                                             alloc_inode,
                                             bg,
                                             group_bh,
-                                            *bit_off,
-                                            *num_bits);
+                                            res->sr_bit_offset,
+                                            res->sr_bits);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
         }
 
-        mlog(0, "Allocated %u bits from suballocator %llu\n", *num_bits,
+        mlog(0, "Allocated %u bits from suballocator %llu\n", res->sr_bits,
              (unsigned long long)le64_to_cpu(fe->i_blkno));
 
-        *bg_blkno = le64_to_cpu(bg->bg_blkno);
         *bits_left = le16_to_cpu(bg->bg_free_bits_count);
 bail:
         brelse(group_bh);
@@ -1782,14 +1769,11 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
                                      handle_t *handle,
                                      u32 bits_wanted,
                                      u32 min_bits,
-                                     u16 *bit_off,
-                                     unsigned int *num_bits,
-                                     u64 *bg_blkno)
+                                     struct ocfs2_suballoc_result *res)
 {
         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;
 
@@ -1816,22 +1800,16 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
                 goto bail;
         }
 
-        if (hint_blkno) {
+        res->sr_bg_blkno = ac->ac_last_group;
+        if (res->sr_bg_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, handle, 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;
+                                                min_bits, res, &bits_left);
+                if (!status)
                         goto set_hint;
-                }
                 if (status < 0 && status != -ENOSPC) {
                         mlog_errno(status);
                         goto bail;
@@ -1844,8 +1822,8 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
         ac->ac_chain = victim;
         ac->ac_allow_chain_relink = 1;
 
-        status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits, bit_off,
-                                    num_bits, bg_blkno, &bits_left);
+        status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits,
+                                    res, &bits_left);
         if (!status)
                 goto set_hint;
         if (status < 0 && status != -ENOSPC) {
@@ -1869,8 +1847,7 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
 
                 ac->ac_chain = i;
                 status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits,
-                                            bit_off, num_bits, bg_blkno,
-                                            &bits_left);
+                                            res, &bits_left);
                 if (!status)
                         break;
                 if (status < 0 && status != -ENOSPC) {
@@ -1887,7 +1864,7 @@ set_hint:
                 if (bits_left < min_bits)
                         ac->ac_last_group = 0;
                 else
-                        ac->ac_last_group = *bg_blkno;
+                        ac->ac_last_group = res->sr_bg_blkno;
         }
 
 bail:
@@ -1904,7 +1881,7 @@ int ocfs2_claim_metadata(struct ocfs2_super *osb,
                          u64 *blkno_start)
 {
         int status;
-        u64 bg_blkno;
+        struct ocfs2_suballoc_result res;
 
         BUG_ON(!ac);
         BUG_ON(ac->ac_bits_wanted < (ac->ac_bits_given + bits_wanted));
@@ -1915,17 +1892,17 @@ int ocfs2_claim_metadata(struct ocfs2_super *osb,
                                            handle,
                                            bits_wanted,
                                            1,
-                                           suballoc_bit_start,
-                                           num_bits,
-                                           &bg_blkno);
+                                           &res);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
         }
         atomic_inc(&osb->alloc_stats.bg_allocs);
 
-        *blkno_start = bg_blkno + (u64) *suballoc_bit_start;
-        ac->ac_bits_given += (*num_bits);
+        *suballoc_bit_start = res.sr_bit_offset;
+        *blkno_start = res.sr_bg_blkno + (u64)(res.sr_bit_offset);
+        ac->ac_bits_given += res.sr_bits;
+        *num_bits = res.sr_bits;
         status = 0;
 bail:
         mlog_exit(status);
@@ -1972,8 +1949,7 @@ int ocfs2_claim_new_inode(struct ocfs2_super *osb,
                           u64 *fe_blkno)
 {
         int status;
-        unsigned int num_bits;
-        u64 bg_blkno;
+        struct ocfs2_suballoc_result res;
 
         mlog_entry_void();
 
@@ -1989,18 +1965,17 @@ int ocfs2_claim_new_inode(struct ocfs2_super *osb,
                                            handle,
                                            1,
                                            1,
-                                           suballoc_bit,
-                                           &num_bits,
-                                           &bg_blkno);
+                                           &res);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
         }
         atomic_inc(&osb->alloc_stats.bg_allocs);
 
-        BUG_ON(num_bits != 1);
+        BUG_ON(res.sr_bits != 1);
 
-        *fe_blkno = bg_blkno + (u64) (*suballoc_bit);
+        *suballoc_bit = res.sr_bit_offset;
+        *fe_blkno = res.sr_bg_blkno + (u64)(res.sr_bit_offset);
         ac->ac_bits_given++;
         ocfs2_save_inode_ac_group(dir, ac);
         status = 0;
@@ -2080,8 +2055,7 @@ int __ocfs2_claim_clusters(struct ocfs2_super *osb,
 {
         int status;
         unsigned int bits_wanted = max_clusters;
-        u64 bg_blkno = 0;
-        u16 bg_bit_off;
+        struct ocfs2_suballoc_result res;
 
         mlog_entry_void();
 
@@ -2120,14 +2094,12 @@ int __ocfs2_claim_clusters(struct ocfs2_super *osb,
                                                    handle,
                                                    bits_wanted,
                                                    min_clusters,
-                                                   &bg_bit_off,
-                                                   num_clusters,
-                                                   &bg_blkno);
+                                                   &res);
                 if (!status) {
                         *cluster_start =
                                 ocfs2_desc_bitmap_to_cluster_off(ac->ac_inode,
-                                                                 bg_blkno,
-                                                                 bg_bit_off);
+                                                                 res.sr_bg_blkno,
+                                                                 res.sr_bit_offset);
                         atomic_inc(&osb->alloc_stats.bitmap_data);
                 }
         }
@@ -2137,7 +2109,8 @@ int __ocfs2_claim_clusters(struct ocfs2_super *osb,
                 goto bail;
         }
 
-        ac->ac_bits_given += *num_clusters;
+        ac->ac_bits_given += res.sr_bits;
+        *num_clusters = res.sr_bits;
 
 bail:
         mlog_exit(status);
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index da2f29a55ec3..f5a22cd1640f 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -26,13 +26,14 @@
 #ifndef _CHAINALLOC_H_
 #define _CHAINALLOC_H_
 
+struct ocfs2_suballoc_result;
 typedef int (group_search_t)(struct inode *,
                              struct buffer_head *,
                              u32,                       /* bits_wanted */
                              u32,                       /* min_bits */
                              u64,                       /* max_block */
-                             u16 *,                     /* *bit_off */
-                             u16 *);                    /* *bits_found */
+                             struct ocfs2_suballoc_result *);
+                                                        /* found bits */
 
 struct ocfs2_alloc_context {
         struct inode *ac_inode;    /* which bitmap are we allocating from? */