From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> When we're reflinking between two files and the destination file range is well beyond the destination file's EOF marker, zero any posteof speculative preallocations in the destination file so that we don't expose stale disk contents. The previous strategy of trying to clear the preallocations does not work if the destination file has the PREALLOC flag set but no delalloc blocks. Uncovered by shared/010. Reported-by: Zorro Lang <zlang@xxxxxxxxxx> Bugzilla-id: https://bugzilla.kernel.org/show_bug.cgi?id=201259 Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> --- fs/xfs/xfs_reflink.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 38f405415b88..c8e996a99a74 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1195,6 +1195,27 @@ xfs_iolock_two_inodes_and_break_layout( return 0; } +/* + * If we're reflinking to a point past the destination file's EOF, we must + * zero any speculative post-EOF preallocations that sit between the old EOF + * and the destination file offset. + */ +static int +xfs_reflink_zero_posteof( + struct xfs_inode *ip, + loff_t pos) +{ + loff_t isize = i_size_read(VFS_I(ip)); + bool did_zeroing = false; + + if (pos <= isize) + return 0; + + trace_xfs_zero_eof(ip, isize, pos - isize); + return iomap_zero_range(VFS_I(ip), isize, pos - isize, &did_zeroing, + &xfs_iomap_ops); +} + /* * Link a range of blocks from one file to another. */ @@ -1257,15 +1278,12 @@ xfs_reflink_remap_range( trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out); /* - * Clear out post-eof preallocations because we don't have page cache - * backing the delayed allocations and they'll never get freed on - * their own. + * Zero existing post-eof speculative preallocations in the destination + * file. */ - if (xfs_can_free_eofblocks(dest, true)) { - ret = xfs_free_eofblocks(dest); - if (ret) - goto out_unlock; - } + ret = xfs_reflink_zero_posteof(dest, pos_out); + if (ret) + goto out_unlock; /* Set flags and remap blocks. */ ret = xfs_reflink_set_inode_flag(src, dest);
