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Commit 65bfa658 authored by Chandan Rajendra's avatar Chandan Rajendra Committed by David Sterba
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Btrfs: btrfs_ioctl_clone: Truncate complete page after performing clone operation 



In subpagesize-blocksize scenario, the "destination offset" argument passed to
the btrfs_ioctl_clone() can be aligned to sectorsize but may not be
necessarily aligned to the machine's page size. In such cases,
truncate_inode_pages_range() ends up zeroing out the partial page and future
read operations will return incorrect data. Hence this commit explicitly
rounds down the "destination offset" to the machine's page size.

Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 27772b68

fs/btrfs/ioctl.c

+3 −2
Original line number Diff line number Diff line
@@ -3926,8 +3926,9 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, 
	 * Truncate page cache pages so that future reads will see the cloned

	 * data immediately and not the previous data.

	 */

	truncate_inode_pages_range(&inode->i_data, destoff,

				   PAGE_CACHE_ALIGN(destoff + len) - 1);

	truncate_inode_pages_range(&inode->i_data,

				round_down(destoff, PAGE_CACHE_SIZE),

				round_up(destoff + len, PAGE_CACHE_SIZE) - 1);

out_unlock:

	if (!same_inode)

		btrfs_double_inode_unlock(src, inode);