XFS transactions are constrained both by space and block reservation
limits and the fact that we have to avoid doing 64-bit divisions. This
means that we can't remap more than 2^32 blocks at a time. However,
file logical blocks are 64-bit in size, so if we encounter a huge remap
request we have to break it up into smaller pieces.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_reflink.c | 83 ++++++++++++++++++++++++++++++--------------------
1 file changed, 49 insertions(+), 34 deletions(-)
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index ffe6fe7..bb61bb2 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -675,49 +675,29 @@ xfs_reflink_cancel_cow_range(
return error;
}
-/*
- * Remap parts of a file's data fork after a successful CoW.
- */
-int
-xfs_reflink_end_cow(
+/* Remap a particular subrange of a file. */
+STATIC int
+xfs_reflink_end_cow_range(
struct xfs_inode *ip,
- xfs_off_t offset,
- xfs_off_t count)
+ struct xfs_ifork *ifp,
+ xfs_fileoff_t offset_fsb,
+ xfs_fileoff_t end_fsb)
{
- struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
- struct xfs_bmbt_irec got, del;
+ struct xfs_bmbt_irec got;
+ struct xfs_bmbt_irec del;
+ struct xfs_defer_ops dfops;
struct xfs_trans *tp;
- xfs_fileoff_t offset_fsb;
- xfs_fileoff_t end_fsb;
xfs_fsblock_t firstfsb;
- struct xfs_defer_ops dfops;
- int error;
- unsigned int resblks;
xfs_filblks_t rlen;
+ unsigned int resblks;
xfs_extnum_t idx;
-
- trace_xfs_reflink_end_cow(ip, offset, count);
-
- /* No COW extents? That's easy! */
- if (ifp->if_bytes == 0)
- return 0;
-
- offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
- end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
+ int error;
/*
- * Start a rolling transaction to switch the mappings. We're
- * unlikely ever to have to remap 16T worth of single-block
- * extents, so just cap the worst case extent count to 2^32-1.
- * Stick a warning in just in case, and avoid 64-bit division.
+ * Start a rolling transaction to switch the mappings.
+ * Avoid 64-bit division.
*/
- BUILD_BUG_ON(MAX_RW_COUNT > UINT_MAX);
- if (end_fsb - offset_fsb > UINT_MAX) {
- error = -EFSCORRUPTED;
- xfs_force_shutdown(ip->i_mount, SHUTDOWN_CORRUPT_INCORE);
- ASSERT(0);
- goto out;
- }
+ ASSERT(end_fsb - offset_fsb <= UINT_MAX);
resblks = XFS_NEXTENTADD_SPACE_RES(ip->i_mount,
(unsigned int)(end_fsb - offset_fsb),
XFS_DATA_FORK);
@@ -812,6 +792,41 @@ xfs_reflink_end_cow(
}
/*
+ * Remap parts of a file's data fork after a successful CoW.
+ */
+int
+xfs_reflink_end_cow(
+ struct xfs_inode *ip,
+ xfs_off_t offset,
+ xfs_off_t count)
+{
+ struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
+ xfs_fileoff_t offset_fsb;
+ xfs_fileoff_t end_fsb;
+ xfs_fileoff_t opend;
+ int error = 0;
+
+ trace_xfs_reflink_end_cow(ip, offset, count);
+
+ /* No COW extents? That's easy! */
+ if (ifp->if_bytes == 0)
+ return 0;
+
+ offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
+ end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
+
+ while (offset_fsb < end_fsb) {
+ opend = min_t(xfs_fileoff_t, offset_fsb + UINT_MAX, end_fsb);
+ error = xfs_reflink_end_cow_range(ip, ifp, offset_fsb, opend);
+ if (error)
+ break;
+ offset_fsb = opend;
+ }
+
+ return error;
+}
+
+/*
* Free leftover CoW reservations that didn't get cleaned out.
*/
int
--
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