1 files changed, 42 insertions, 16 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 58005c01abb8..1707850301d6 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1602,6 +1602,32 @@ out:
         return ret;
 }
 
+int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
+                                                ext4_fsblk_t nblocks)
+{
+        s64 free_blocks;
+        ext4_fsblk_t root_blocks = 0;
+        struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+
+        free_blocks = percpu_counter_read(fbc);
+
+        if (!capable(CAP_SYS_RESOURCE) &&
+                sbi->s_resuid != current->fsuid &&
+                (sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
+                root_blocks = ext4_r_blocks_count(sbi->s_es);
+
+        if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
+                free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter);
+
+        if (free_blocks < (root_blocks + nblocks))
+                /* we don't have free space */
+                return -ENOSPC;
+
+        /* reduce fs free blocks counter */
+        percpu_counter_sub(fbc, nblocks);
+        return 0;
+}
+
 /**
  * ext4_has_free_blocks()
  * @sbi:        in-core super block structure.
@@ -1623,18 +1649,17 @@ ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
                 sbi->s_resuid != current->fsuid &&
                 (sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
                 root_blocks = ext4_r_blocks_count(sbi->s_es);
-#ifdef CONFIG_SMP
-        if (free_blocks - root_blocks < FBC_BATCH)
-                free_blocks =
-                        percpu_counter_sum(&sbi->s_freeblocks_counter);
-#endif
+
+        if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
+                free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
+
         if (free_blocks <= root_blocks)
                 /* we don't have free space */
                 return 0;
         if (free_blocks - root_blocks < nblocks)
                 return free_blocks - root_blocks;
         return nblocks;
- }
+}
 
 
 /**
@@ -1713,14 +1738,11 @@ ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
                 /*
                  * With delalloc we already reserved the blocks
                  */
-                *count = ext4_has_free_blocks(sbi, *count);
-        }
-        if (*count == 0) {
-                *errp = -ENOSPC;
-                return 0;       /*return with ENOSPC error */
+                if (ext4_claim_free_blocks(sbi, *count)) {
+                        *errp = -ENOSPC;
+                        return 0;       /*return with ENOSPC error */
+                }
         }
-        num = *count;
-
         /*
          * Check quota for allocation of this block.
          */
@@ -1915,9 +1937,13 @@ allocated:
         le16_add_cpu(&gdp->bg_free_blocks_count, -num);
         gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
         spin_unlock(sb_bgl_lock(sbi, group_no));
-        if (!EXT4_I(inode)->i_delalloc_reserved_flag)
-                percpu_counter_sub(&sbi->s_freeblocks_counter, num);
-
+        if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) {
+                /*
+                 * we allocated less blocks than we
+                 * claimed. Add the difference back.
+                 */
+                percpu_counter_add(&sbi->s_freeblocks_counter, *count - num);
+        }
         if (sbi->s_log_groups_per_flex) {
                 ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
                 spin_lock(sb_bgl_lock(sbi, flex_group));