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Btrfs: btrfs_ioctl_clone: Truncate complete page after performing clone operation

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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: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Chandan Rajendra 2016-01-21 15:56:04 +05:30 committed by David Sterba
parent 27772b68f6
commit 65bfa65807
1 changed files with 3 additions and 2 deletions
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5
fs/btrfs/ioctl.c
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@ -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);