ocfs2: simplify deallocation locking

Deallocation of suballocator blocks, most notably extent blocks, might
involve multiple suballocator inodes.

The locking for this can get extremely complicated, especially when the
suballocator inodes to delete from aren't known until deep within an
unrelated codepath.

Implement a simple scheme for recording the blocks to be unlinked so that
the actual deallocation can be done in a context which won't deadlock.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 1a3c94cb9250..7bc4819db4db 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -86,6 +86,12 @@ int ocfs2_claim_clusters(struct ocfs2_super *osb,
                          u32 *cluster_start,
                          u32 *num_clusters);
 
+int ocfs2_free_suballoc_bits(handle_t *handle,
+                             struct inode *alloc_inode,
+                             struct buffer_head *alloc_bh,
+                             unsigned int start_bit,
+                             u64 bg_blkno,
+                             unsigned int count);
 int ocfs2_free_dinode(handle_t *handle,
                       struct inode *inode_alloc_inode,
                       struct buffer_head *inode_alloc_bh,
@@ -100,6 +106,13 @@ int ocfs2_free_clusters(handle_t *handle,
                         u64 start_blk,
                         unsigned int num_clusters);
 
+static inline u64 ocfs2_which_suballoc_group(u64 block, unsigned int bit)
+{
+        u64 group = block - (u64) bit;
+
+        return group;
+}
+
 static inline u32 ocfs2_cluster_from_desc(struct ocfs2_super *osb,
                                           u64 bg_blkno)
 {