b=20190

i=adilger
i=rahul

fix deadlock due to wrong locking in ext4_mb_free_metadata()

diff --git a/ldiskfs/kernel_patches/patches/ext4-convert-group-lock-rhel5.patch b/ldiskfs/kernel_patches/patches/ext4-convert-group-lock-rhel5.patch
index 370b2e7..8f714f8 100644 (file)
--- a/ldiskfs/kernel_patches/patches/ext4-convert-group-lock-rhel5.patch
+++ b/ldiskfs/kernel_patches/patches/ext4-convert-group-lock-rhel5.patch
@@ -423,7 +423,43 @@ Index: linux-2.6.18-128.1.6/fs/ext4/mballoc.c
                preallocated += len;
                count++;
        }
                preallocated += len;
                count++;
        }

-@@ -4901,6 +4889,13 @@ do_more:
+@@ -4742,6 +4730,7 @@ static void ext4_mb_poll_new_transaction
+       ext4_mb_free_committed_blocks(sb);
+ }
+ 
++/* need to be called with ldiskfs group lock held */
+ static noinline_for_stack int
+ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
+                         ext4_group_t group, ext4_grpblk_t block, int count)
+@@ -4755,7 +4744,6 @@ ext4_mb_free_metadata(handle_t *handle, 
+       BUG_ON(e4b->bd_bitmap_page == NULL);
+       BUG_ON(e4b->bd_buddy_page == NULL);
+ 
+-      ext4_lock_group(sb, group);
+       for (i = 0; i < count; i++) {
+               md = db->bb_md_cur;
+               if (md && db->bb_tid != handle->h_transaction->t_tid) {
+@@ -4766,8 +4754,10 @@ ext4_mb_free_metadata(handle_t *handle, 
+               if (md == NULL) {
+                       ext4_unlock_group(sb, group);
+                       md = kmalloc(sizeof(*md), GFP_NOFS);
+-                      if (md == NULL)
++                      if (md == NULL) {
++                              ext4_lock_group(sb, group);
+                               return -ENOMEM;
++                      }
+                       md->num = 0;
+                       md->group = group;
+ 
+@@ -4800,7 +4790,6 @@ ext4_mb_free_metadata(handle_t *handle, 
+                       db->bb_md_cur = NULL;
+               }
+       }
+-      ext4_unlock_group(sb, group);
+       return 0;
+ }
+ 
+@@ -4901,6 +4890,13 @@ do_more:

        if (err)
                goto error_return;
  
        if (err)
                goto error_return;
  


@@ -437,7 +473,7 @@ Index: linux-2.6.18-128.1.6/fs/ext4/mballoc.c
        err = ext4_mb_load_buddy(sb, block_group, &e4b);
        if (err)
                goto error_return;
        err = ext4_mb_load_buddy(sb, block_group, &e4b);
        if (err)
                goto error_return;

-@@ -4912,42 +4907,31 @@ do_more:
+@@ -4912,42 +4908,31 @@ do_more:

                        BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
        }
  #endif
                        BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
        }
  #endif


@@ -553,7 +589,7 @@ Index: linux-2.6.18-128.1.6/fs/ext4/mballoc.h
 ===================================================================
 --- linux-2.6.18-128.1.6.orig/fs/ext4/mballoc.h
 +++ linux-2.6.18-128.1.6/fs/ext4/mballoc.h
 ===================================================================
 --- linux-2.6.18-128.1.6.orig/fs/ext4/mballoc.h
 +++ linux-2.6.18-128.1.6/fs/ext4/mballoc.h

-@@ -126,7 +126,6 @@ struct ext4_group_info {
+@@ -127,7 +127,6 @@ struct ext4_group_info {

  };
  
  #define EXT4_GROUP_INFO_NEED_INIT_BIT 0
  };
  
  #define EXT4_GROUP_INFO_NEED_INIT_BIT 0