| Message ID | 153870029414.29072.6572683664719818617.stgit@magnolia (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | fs: fixes for serious clone/dedupe problems | expand |
On Thu, Oct 04, 2018 at 05:44:54PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > 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. > > Uncovered by shared/010. > > Reported-by: Zorro Lang <zlang@redhat.com> > Bugzilla-id: https://bugzilla.kernel.org/show_bug.cgi?id=201259 > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- > fs/xfs/xfs_reflink.c | 33 +++++++++++++++++++++++++-------- > 1 file changed, 25 insertions(+), 8 deletions(-) Looks good. Reviewed-by: Dave Chinner <dchinner@redhat.com>
On Thu, Oct 04, 2018 at 05:44:54PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > 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 I think we should still drop speculative delalloc preallocations instead of zeroing them in addition to zeroing of any real blocks in the data fork.
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 80ca9b6793cd..55da7e1154f4 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1215,6 +1215,26 @@ xfs_reflink_remap_unlock( inode_unlock_shared(inode_in); } +/* + * 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)); + + if (pos <= isize) + return 0; + + trace_xfs_zero_eof(ip, isize, pos - isize); + return iomap_zero_range(VFS_I(ip), isize, pos - isize, NULL, + &xfs_iomap_ops); +} + /* * Prepare two files for range cloning. Upon a successful return both inodes * will have the iolock and mmaplock held, the page cache of the out file @@ -1267,15 +1287,12 @@ xfs_reflink_remap_prep( goto out_unlock; /* - * 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);