Ok, you can add my review
Reviewed-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
On 06/21/2018 11:31 AM, Darrick J. Wong wrote:
From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Zorro Lang reports that generic/485 blows an assert on a filesystem with
512 byte blocks. The test tries to fallocate a post-eof extent at the
maximum file size and calls insert range to shift the extents right by
two blocks. On a 512b block filesystem this causes startoff to overflow
the 54-bit startoff field, leading to the assert.
Therefore, always check the rightmost extent to see if it would overflow
prior to invoking the insert range machinery.
Reported-by: zlang@xxxxxxxxxx
Bugzilla: https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.kernel.org_show-5Fbug.cgi-3Fid-3D200137&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=LHZQ8fHvy6wDKXGTWcm97burZH5sQKHRDMaY1UthQxc&m=YCaDC-F1dLxMWur8rwN6LkUZEkB0mCLT1kaX18afe3Y&s=21OAUtb7E_eZcNMI0iepr7J9fg90RHPo0hUJBgJxDrI&e=
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 40 ++++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_bmap.h | 2 ++
fs/xfs/xfs_bmap_util.c | 4 ++++
3 files changed, 46 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 01628f0c9a0c..b7f094e19bab 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5780,6 +5780,46 @@ xfs_bmap_collapse_extents(
return error;
}
+#define BMBT_STARTOFF_MASK ((1ULL << BMBT_STARTOFF_BITLEN) - 1)
+/* Make sure we won't be right-shifting an extent past the maximum bound. */
+int
+xfs_bmap_can_insert_extents(
+ struct xfs_inode *ip,
+ xfs_fileoff_t off,
+ xfs_fileoff_t shift)
+{
+ struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+ struct xfs_bmbt_irec got;
+ struct xfs_iext_cursor icur;
+ xfs_fileoff_t new_off;
+ int error = 0;
+
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return -EIO;
+
+ ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+ if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+ error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
+ if (error)
+ goto out;
+ }
+
+ xfs_iext_last(ifp, &icur);
+ if (!xfs_iext_get_extent(ifp, &icur, &got) || off > got.br_startoff)
+ goto out;
+
+ /* Make sure we can't overflow the 54-bit offset field. */
+ new_off = (got.br_startoff + shift) & BMBT_STARTOFF_MASK;
+ if (new_off < got.br_startoff)
+ error = -EINVAL;
+
+out:
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+}
+
int
xfs_bmap_insert_extents(
struct xfs_trans *tp,
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index 99dddbd0fcc6..9b49ddf99c41 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -227,6 +227,8 @@ int xfs_bmap_collapse_extents(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t *next_fsb, xfs_fileoff_t offset_shift_fsb,
bool *done, xfs_fsblock_t *firstblock,
struct xfs_defer_ops *dfops);
+int xfs_bmap_can_insert_extents(struct xfs_inode *ip, xfs_fileoff_t off,
+ xfs_fileoff_t shift);
int xfs_bmap_insert_extents(struct xfs_trans *tp, struct xfs_inode *ip,
xfs_fileoff_t *next_fsb, xfs_fileoff_t offset_shift_fsb,
bool *done, xfs_fileoff_t stop_fsb, xfs_fsblock_t *firstblock,
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index c35009a86699..abc37b0899c0 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1404,6 +1404,10 @@ xfs_insert_file_space(
trace_xfs_insert_file_space(ip);
+ error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
+ if (error)
+ return error;
+
error = xfs_prepare_shift(ip, offset);
if (error)
return error;
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