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Message-ID: <20080205200637.GA6490@skywalker>
Date: Wed, 6 Feb 2008 01:36:37 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: Jan Kara <jack@...e.cz>
Cc: Josef Bacik <jbacik@...hat.com>, Theodore Tso <tytso@....edu>,
Andreas Dilger <adilger@....com>,
Mingming Cao <cmm@...ibm.com>,
"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: jbd2_handle and i_data_sem circular locking dependency detected
On Tue, Feb 05, 2008 at 05:34:04PM +0100, Jan Kara wrote:
> On Tue 05-02-08 21:57:03, Aneesh Kumar K.V wrote:
> >
> > I have a FIXME at migrate.c:524 documenting exactly that. The
> > difficult question was by how much we should extent the journal. ? But
> > in reality we might have accumulated enough journal credits, I never
> > really ran across a case where we are running out of the journal credit.
> Yes, I don't think it is likely to happen in reality but if somebody
> would trigger this, it would be almost impossible to track down so one
> should be quite careful with these things...
> And as I described, doing it failsafe is easy - just look how
> try_to_extend_transaction() in ext4/inode.c handles similar problems with
> truncate.
>
I moved the indirect block freeing after i update the original inode.
That makes sure even if we fail to free the indirect blocks we have the
original inode converted. Now since i don't need atomicity with freeing of
blocks i extend the journal for each block freed. Below is the diff i have
right now.
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index 1712844..1b00587 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -233,11 +233,14 @@ static int free_dind_blocks(handle_t *handle,
tmp_idata = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
- if (tmp_idata[i])
+ if (tmp_idata[i]) {
+ extend_blkdelete_credit(handle, inode);
ext4_free_blocks(handle, inode,
le32_to_cpu(tmp_idata[i]), 1, 1);
+ }
}
put_bh(bh);
+ extend_blkdelete_credit(handle, inode);
ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
return 0;
}
@@ -266,29 +269,32 @@ static int free_tind_blocks(handle_t *handle,
}
}
put_bh(bh);
+ extend_blkdelete_credit(handle, inode);
ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
return 0;
}
-static int free_ind_block(handle_t *handle, struct inode *inode)
+static int free_ind_block(handle_t *handle, __le32 *i_data)
{
int retval;
- struct ext4_inode_info *ei = EXT4_I(inode);
- if (ei->i_data[EXT4_IND_BLOCK])
+ /* ei->i_data[EXT4_IND_BLOCK] */
+ if (i_data[0]) {
+ extend_blkdelete_credit(handle, inode);
ext4_free_blocks(handle, inode,
- le32_to_cpu(ei->i_data[EXT4_IND_BLOCK]), 1, 1);
+ le32_to_cpu(i_data[0]), 1, 1);
+ }
- if (ei->i_data[EXT4_DIND_BLOCK]) {
- retval = free_dind_blocks(handle, inode,
- ei->i_data[EXT4_DIND_BLOCK]);
+ /* ei->i_data[EXT4_DIND_BLOCK] */
+ if (i_data[1]) {
+ retval = free_dind_blocks(handle, inode, i_data[1]);
if (retval)
return retval;
}
- if (ei->i_data[EXT4_TIND_BLOCK]) {
- retval = free_tind_blocks(handle, inode,
- ei->i_data[EXT4_TIND_BLOCK]);
+ /* ei->i_data[EXT4_TIND_BLOCK] */
+ if (i_data[2]) {
+ retval = free_tind_blocks(handle, inode, i_data[2]);
if (retval)
return retval;
}
@@ -299,6 +305,7 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
struct inode *tmp_inode)
{
int retval;
+ __le32 i_data[3];
struct ext4_inode_info *ei = EXT4_I(inode);
struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
@@ -313,11 +320,11 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
goto err_out;
}
- down_write(&EXT4_I(inode)->i_data_sem);
- retval = free_ind_block(handle, inode);
- if (retval)
- goto err_out;
+ i_data[0] = ei->i_data[EXT4_IND_BLOCK];
+ i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
+ i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
+ down_write(&EXT4_I(inode)->i_data_sem);
/*
* We have the extent map build with the tmp inode.
* Now copy the i_data across
@@ -338,8 +345,12 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
inode->i_blocks += tmp_inode->i_blocks;
spin_unlock(&inode->i_lock);
up_write(&EXT4_I(inode)->i_data_sem);
-
ext4_mark_inode_dirty(handle, inode);
+
+ /* Now free the indirec block of the inode */
+ retval = free_ind_block(handle, i_data);
+ if (retval)
+ goto err_out;
err_out:
return retval;
}
@@ -367,6 +378,7 @@ static int free_ext_idx(handle_t *handle, struct inode *inode,
}
}
put_bh(bh);
+ extend_blkdelete_credit(handle, inode);
ext4_free_blocks(handle, inode, block, 1, 1);
return retval;
}
@@ -394,6 +406,25 @@ static int free_ext_block(handle_t *handle, struct inode *inode)
return retval;
}
+static int extend_blkdelete_credit(handle_t *handle, struct inode *inode)
+{
+ int retval, needed;
+
+ if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
+ return 0;
+ /*
+ * We are freeing a blocks. During this we touch
+ * superblock, group descriptor and block bitmap.
+ * So allocate a credit of 3. We may update
+ * quota (user and group).
+ */
+ needed = 3 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
+
+ if (ext4_journal_extend(handle, needed) != 0)
+ retval = ext4_journal_restart(handle, needed);
+
+ return retval;
+}
int ext4_ext_migrate(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
@@ -514,19 +545,6 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
*/
retval = finish_range(handle, tmp_inode, &lb);
err_out:
- /*
- * We are either freeing extent information or indirect
- * blocks. During this we touch superblock, group descriptor
- * and block bitmap. Later we mark the tmp_inode dirty
- * via ext4_ext_tree_init. So allocate a credit of 4
- * We may update quota (user and group).
- *
- * FIXME!! we may be touching bitmaps in different block groups.
- */
- if (ext4_journal_extend(handle,
- 4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb)) != 0)
- ext4_journal_restart(handle,
- 4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
if (retval)
/*
* Failure case delete the extent information with the
@@ -537,6 +555,10 @@ err_out:
retval = ext4_ext_swap_inode_data(handle, inode,
tmp_inode);
+ /* We mark the tmp_inode dirty via ext4_ext_tree_init. */
+ if (ext4_journal_extend(handle, 1) != 0)
+ ext4_journal_restart(handle, 1);
+
/*
* Mark the tmp_inode as of size zero
*/
-
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