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Btrfs: Fix lock ordering of the snapshot semaphore against the page lock 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
hifive-unleashed-5.1
Chris Mason 2008-01-03 13:46:11 -05:00
parent bd09835d9a
commit 5b92ee7204
1 changed files with 4 additions and 2 deletions
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6
fs/btrfs/file.c
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@ -251,7 +251,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
num_bytes = (write_bytes + pos - start_pos +
root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
down_read(&BTRFS_I(inode)->root->snap_sem);
end_of_last_block = start_pos + num_bytes - 1;
lock_extent(em_tree, start_pos, end_of_last_block, GFP_NOFS);
@ -356,7 +355,6 @@ out_unlock:
mutex_unlock(&root->fs_info->fs_mutex);
unlock_extent(em_tree, start_pos, end_of_last_block, GFP_NOFS);
free_extent_map(em);
up_read(&BTRFS_I(inode)->root->snap_sem);
return err;
}
@ -726,6 +724,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
down_read(&BTRFS_I(inode)->root->snap_sem);
mutex_lock(&inode->i_mutex);
first_index = pos >> PAGE_CACHE_SHIFT;
last_index = (pos + count) >> PAGE_CACHE_SHIFT;
@ -804,6 +804,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
}
out:
mutex_unlock(&inode->i_mutex);
up_read(&BTRFS_I(inode)->root->snap_sem);
out_nolock:
kfree(pages);
if (pinned[0])