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ext4: Fix locking hierarchy violation in ext4_fallocate()

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ext4_fallocate() was trying to acquire i_data_sem outside of
jbd2_start_transaction/jbd2_journal_stop, which violates ext4's locking
hierarchy.  So we take i_mutex to prevent writes and truncates during
the complete fallocate operation, and use ext4_get_block_wrap() which
acquires and releases i_data_sem for each block allocation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Aneesh Kumar K.V 2008-02-15 12:47:21 -05:00 committed by Theodore Ts'o
parent 642be6ec21
commit 55bd725aa3
1 changed files with 3 additions and 7 deletions
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10
fs/ext4/extents.c
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@ -2623,7 +2623,7 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
* modify 1 super block, 1 block bitmap and 1 group descriptor.
*/
credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
down_write((&EXT4_I(inode)->i_data_sem));
mutex_lock(&inode->i_mutex);
retry:
while (ret >= 0 && ret < max_blocks) {
block = block + ret;
@ -2634,7 +2634,7 @@ retry:
break;
}
ret = ext4_ext_get_blocks(handle, inode, block,
ret = ext4_get_blocks_wrap(handle, inode, block,
max_blocks, &map_bh,
EXT4_CREATE_UNINITIALIZED_EXT, 0);
WARN_ON(ret <= 0);
@ -2680,7 +2680,6 @@ retry:
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
up_write((&EXT4_I(inode)->i_data_sem));
/*
* Time to update the file size.
* Update only when preallocation was requested beyond the file size.
@ -2692,21 +2691,18 @@ retry:
* if no error, we assume preallocation succeeded
* completely
*/
mutex_lock(&inode->i_mutex);
i_size_write(inode, offset + len);
EXT4_I(inode)->i_disksize = i_size_read(inode);
mutex_unlock(&inode->i_mutex);
} else if (ret < 0 && nblocks) {
/* Handle partial allocation scenario */
loff_t newsize;
mutex_lock(&inode->i_mutex);
newsize = (nblocks << blkbits) + i_size_read(inode);
i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits));
EXT4_I(inode)->i_disksize = i_size_read(inode);
mutex_unlock(&inode->i_mutex);
}
}
mutex_unlock(&inode->i_mutex);
return ret > 0 ? ret2 : ret;
}