[PATCH 35/39] ocfs2: Resolve deadlock in ocfs2_xattr_free_block.

Mark Fasheh
2008-09-24T22:13:40Z

From: Tao Ma <tao.ma@oracle.com>

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>
---
fs/ocfs2/xattr.c | 152 +++++++++++++++++++++++++++++-------------------------
1 files changed, 82 insertions(+), 70 deletions(-)

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 38e3e5e..b2e25a8 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;
}

--
1.5.4.5