ocfs2: Resolve deadlock in ocfs2_xattr_free_block.

In ocfs2_xattr_free_block, we take a cluster lock on xb_alloc_inode while we
have a transaction open. This will deadlock the downconvert thread, so fix
it.

We can clean up how xattr blocks are removed while here - this patch also
moves the mechanism of releasing xattr block (including both value, xattr
tree and xattr block) into this function.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 82 insertions, 70 deletions

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 38e3e5e216bd..b2e25a828e38 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -1427,51 +1427,6 @@ out:
 
 }
 
-static int ocfs2_xattr_free_block(handle_t *handle,
-                                  struct ocfs2_super *osb,
-                                  struct ocfs2_xattr_block *xb)
-{
-        struct inode *xb_alloc_inode;
-        struct buffer_head *xb_alloc_bh = NULL;
-        u64 blk = le64_to_cpu(xb->xb_blkno);
-        u16 bit = le16_to_cpu(xb->xb_suballoc_bit);
-        u64 bg_blkno = ocfs2_which_suballoc_group(blk, bit);
-        int ret = 0;
-
-        xb_alloc_inode = ocfs2_get_system_file_inode(osb,
-                                EXTENT_ALLOC_SYSTEM_INODE,
-                                le16_to_cpu(xb->xb_suballoc_slot));
-        if (!xb_alloc_inode) {
-                ret = -ENOMEM;
-                mlog_errno(ret);
-                goto out;
-        }
-        mutex_lock(&xb_alloc_inode->i_mutex);
-
-        ret = ocfs2_inode_lock(xb_alloc_inode, &xb_alloc_bh, 1);
-        if (ret < 0) {
-                mlog_errno(ret);
-                goto out_mutex;
-        }
-        ret = ocfs2_extend_trans(handle, OCFS2_SUBALLOC_FREE);
-        if (ret < 0) {
-                mlog_errno(ret);
-                goto out_unlock;
-        }
-        ret = ocfs2_free_suballoc_bits(handle, xb_alloc_inode, xb_alloc_bh,
-                                       bit, bg_blkno, 1);
-        if (ret < 0)
-                mlog_errno(ret);
-out_unlock:
-        ocfs2_inode_unlock(xb_alloc_inode, 1);
-        brelse(xb_alloc_bh);
-out_mutex:
-        mutex_unlock(&xb_alloc_inode->i_mutex);
-        iput(xb_alloc_inode);
-out:
-        return ret;
-}
-
 static int ocfs2_remove_value_outside(struct inode*inode,
                                       struct buffer_head *bh,
                                       struct ocfs2_xattr_header *header)
@@ -1533,6 +1488,84 @@ static int ocfs2_xattr_block_remove(struct inode *inode,
         return ret;
 }
 
+static int ocfs2_xattr_free_block(struct inode *inode,
+                                  u64 block)
+{
+        struct inode *xb_alloc_inode;
+        struct buffer_head *xb_alloc_bh = NULL;
+        struct buffer_head *blk_bh = NULL;
+        struct ocfs2_xattr_block *xb;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+        handle_t *handle;
+        int ret = 0;
+        u64 blk, bg_blkno;
+        u16 bit;
+
+        ret = ocfs2_read_block(osb, block, &blk_bh,
+                               OCFS2_BH_CACHED, inode);
+        if (ret < 0) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        /*Verify the signature of xattr block*/
+        if (memcmp((void *)blk_bh->b_data, OCFS2_XATTR_BLOCK_SIGNATURE,
+                   strlen(OCFS2_XATTR_BLOCK_SIGNATURE))) {
+                ret = -EFAULT;
+                goto out;
+        }
+
+        ret = ocfs2_xattr_block_remove(inode, blk_bh);
+        if (ret < 0) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
+        blk = le64_to_cpu(xb->xb_blkno);
+        bit = le16_to_cpu(xb->xb_suballoc_bit);
+        bg_blkno = ocfs2_which_suballoc_group(blk, bit);
+
+        xb_alloc_inode = ocfs2_get_system_file_inode(osb,
+                                EXTENT_ALLOC_SYSTEM_INODE,
+                                le16_to_cpu(xb->xb_suballoc_slot));
+        if (!xb_alloc_inode) {
+                ret = -ENOMEM;
+                mlog_errno(ret);
+                goto out;
+        }
+        mutex_lock(&xb_alloc_inode->i_mutex);
+
+        ret = ocfs2_inode_lock(xb_alloc_inode, &xb_alloc_bh, 1);
+        if (ret < 0) {
+                mlog_errno(ret);
+                goto out_mutex;
+        }
+
+        handle = ocfs2_start_trans(osb, OCFS2_SUBALLOC_FREE);
+        if (IS_ERR(handle)) {
+                ret = PTR_ERR(handle);
+                mlog_errno(ret);
+                goto out_unlock;
+        }
+
+        ret = ocfs2_free_suballoc_bits(handle, xb_alloc_inode, xb_alloc_bh,
+                                       bit, bg_blkno, 1);
+        if (ret < 0)
+                mlog_errno(ret);
+
+        ocfs2_commit_trans(osb, handle);
+out_unlock:
+        ocfs2_inode_unlock(xb_alloc_inode, 1);
+        brelse(xb_alloc_bh);
+out_mutex:
+        mutex_unlock(&xb_alloc_inode->i_mutex);
+        iput(xb_alloc_inode);
+out:
+        brelse(blk_bh);
+        return ret;
+}
+
 /*
  * ocfs2_xattr_remove()
  *
@@ -1540,9 +1573,6 @@ static int ocfs2_xattr_block_remove(struct inode *inode,
  */
 int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh)
 {
-        struct ocfs2_xattr_block *xb;
-        struct buffer_head *blk_bh = NULL;
-        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
         struct ocfs2_inode_info *oi = OCFS2_I(inode);
         struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
         handle_t *handle;
@@ -1561,22 +1591,10 @@ int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh)
                         goto out;
                 }
         }
-        if (di->i_xattr_loc) {
-                ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
-                                       le64_to_cpu(di->i_xattr_loc),
-                                       &blk_bh, OCFS2_BH_CACHED, inode);
-                if (ret < 0) {
-                        mlog_errno(ret);
-                        return ret;
-                }
-                /*Verify the signature of xattr block*/
-                if (memcmp((void *)blk_bh->b_data, OCFS2_XATTR_BLOCK_SIGNATURE,
-                           strlen(OCFS2_XATTR_BLOCK_SIGNATURE))) {
-                        ret = -EFAULT;
-                        goto out;
-                }
 
-                ret = ocfs2_xattr_block_remove(inode, blk_bh);
+        if (di->i_xattr_loc) {
+                ret = ocfs2_xattr_free_block(inode,
+                                             le64_to_cpu(di->i_xattr_loc));
                 if (ret < 0) {
                         mlog_errno(ret);
                         goto out;
@@ -1597,11 +1615,7 @@ int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh)
                 goto out_commit;
         }
 
-        if (di->i_xattr_loc) {
-                xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
-                ocfs2_xattr_free_block(handle, osb, xb);
-                di->i_xattr_loc = cpu_to_le64(0);
-        }
+        di->i_xattr_loc = 0;
 
         spin_lock(&oi->ip_lock);
         oi->ip_dyn_features &= ~(OCFS2_INLINE_XATTR_FL | OCFS2_HAS_XATTR_FL);
@@ -1614,8 +1628,6 @@ int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh)
 out_commit:
         ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
 out:
-        brelse(blk_bh);
-
         return ret;
 }