diff options
| -rw-r--r-- | fs/xfs/libxfs/xfs_bmap.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index fda13cd7add0..f8fe83c9348d 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -4193,17 +4193,7 @@ xfs_bmapi_allocate( bma->got.br_blockcount = bma->length; bma->got.br_state = XFS_EXT_NORM; - /* - * In the data fork, a wasdelay extent has been initialized, so - * shouldn't be flagged as unwritten. - * - * For the cow fork, however, we convert delalloc reservations - * (extents allocated for speculative preallocation) to - * allocated unwritten extents, and only convert the unwritten - * extents to real extents when we're about to write the data. - */ - if ((!bma->wasdel || (bma->flags & XFS_BMAPI_COWFORK)) && - (bma->flags & XFS_BMAPI_PREALLOC)) + if (bma->flags & XFS_BMAPI_PREALLOC) bma->got.br_state = XFS_EXT_UNWRITTEN; if (bma->wasdel) @@ -4611,8 +4601,23 @@ xfs_bmapi_convert_delalloc( bma.offset = bma.got.br_startoff; bma.length = max_t(xfs_filblks_t, bma.got.br_blockcount, MAXEXTLEN); bma.minleft = xfs_bmapi_minleft(tp, ip, whichfork); + + /* + * When we're converting the delalloc reservations backing dirty pages + * in the page cache, we must be careful about how we create the new + * extents: + * + * New CoW fork extents are created unwritten, turned into real extents + * when we're about to write the data to disk, and mapped into the data + * fork after the write finishes. End of story. + * + * New data fork extents must be mapped in as unwritten and converted + * to real extents after the write succeeds to avoid exposing stale + * disk contents if we crash. + */ + bma.flags = XFS_BMAPI_PREALLOC; if (whichfork == XFS_COW_FORK) - bma.flags = XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC; + bma.flags |= XFS_BMAPI_COWFORK; if (!xfs_iext_peek_prev_extent(ifp, &bma.icur, &bma.prev)) bma.prev.br_startoff = NULLFILEOFF; |