From: Chandan Rajendra Date: Thu, 21 Jan 2016 10:26:04 +0000 (+0530) Subject: Btrfs: btrfs_ioctl_clone: Truncate complete page after performing clone operation X-Git-Tag: v4.6-rc1~57^2~16^2~9^2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=65bfa6580791f8c01fbc9cd8bd73d92aea53723f;p=linux.git 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: Chandan Rajendra Signed-off-by: David Sterba --- diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 83c9ad3f2621..709419c98ca5 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -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);