From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Chandan Babu R <chandan.babu@xxxxxxxxxx>
---
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;
--
2.35.1
