From: "Darrick J. Wong" darrick.wong@oracle.com
commit 4bbb04abb4ee2e1f7d65e52557ba1c4038ea43ed upstream.
xfs_itruncate_extents_flags() is supposed to unmap every block in a file from EOF onwards. Oddly, it uses s_maxbytes as the upper limit to the bunmapi range, even though s_maxbytes reflects the highest offset the pagecache can support, not the highest offset that XFS supports.
The result of this confusion is that if you create a 20T file on a 64-bit machine, mount the filesystem on a 32-bit machine, and remove the file, we leak everything above 16T. Fix this by capping the bunmapi request at the maximum possible block offset, not s_maxbytes.
Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Reviewed-by: Christoph Hellwig hch@lst.de Acked-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Chandan Babu R chandan.babu@oracle.com --- fs/xfs/xfs_inode.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 7b72c189cff0..d4af6e44dd6f 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -1513,7 +1513,6 @@ xfs_itruncate_extents_flags( struct xfs_mount *mp = ip->i_mount; struct xfs_trans *tp = *tpp; xfs_fileoff_t first_unmap_block; - xfs_fileoff_t last_block; xfs_filblks_t unmap_len; int error = 0; int done = 0; @@ -1536,21 +1535,22 @@ xfs_itruncate_extents_flags( * the end of the file (in a crash where the space is allocated * but the inode size is not yet updated), simply remove any * blocks which show up between the new EOF and the maximum - * possible file size. If the first block to be removed is - * beyond the maximum file size (ie it is the same as last_block), - * then there is nothing to do. + * possible file size. + * + * We have to free all the blocks to the bmbt maximum offset, even if + * the page cache can't scale that far. */ first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size); - last_block = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); - if (first_unmap_block == last_block) + if (first_unmap_block >= XFS_MAX_FILEOFF) { + WARN_ON_ONCE(first_unmap_block > XFS_MAX_FILEOFF); return 0; + }
- ASSERT(first_unmap_block < last_block); - unmap_len = last_block - first_unmap_block + 1; - while (!done) { + unmap_len = XFS_MAX_FILEOFF - first_unmap_block + 1; + while (unmap_len > 0) { ASSERT(tp->t_firstblock == NULLFSBLOCK); - error = xfs_bunmapi(tp, ip, first_unmap_block, unmap_len, flags, - XFS_ITRUNC_MAX_EXTENTS, &done); + error = __xfs_bunmapi(tp, ip, first_unmap_block, &unmap_len, + flags, XFS_ITRUNC_MAX_EXTENTS); if (error) goto out;
@@ -1570,7 +1570,7 @@ xfs_itruncate_extents_flags( if (whichfork == XFS_DATA_FORK) { /* Remove all pending CoW reservations. */ error = xfs_reflink_cancel_cow_blocks(ip, &tp, - first_unmap_block, last_block, true); + first_unmap_block, XFS_MAX_FILEOFF, true); if (error) goto out;