From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Before we share blocks between files, we need to break the pnfs leases
on the layout before we start slicing and dicing the block map.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_reflink.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 47 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 47aea2e..f89a725 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1245,6 +1245,50 @@ xfs_reflink_remap_blocks(
}
/*
+ * Grab the exclusive iolock for a data copy from src to dest, making
+ * sure to abide vfs locking order (lowest pointer value goes first) and
+ * breaking the pnfs layout leases on dest before proceeding. The loop
+ * is needed because we cannot call the blocking break_layout() with the
+ * src iolock held, and therefore have to back out both locks.
+ */
+static int
+xfs_iolock_two_inodes_and_break_layout(
+ struct inode *src,
+ struct inode *dest)
+{
+ bool src_first = src < dest;
+ bool src_last = src > dest;
+ int error;
+
+retry:
+ if (src_first) {
+ inode_lock(src);
+ inode_lock_nested(dest, I_MUTEX_NONDIR2);
+ } else {
+ inode_lock(dest);
+ }
+
+ error = break_layout(dest, false);
+ if (error == -EWOULDBLOCK) {
+ inode_unlock(dest);
+ if (src_first)
+ inode_unlock(src);
+ error = break_layout(dest, true);
+ if (error)
+ return error;
+ goto retry;
+ } else if (error) {
+ inode_unlock(dest);
+ if (src_first)
+ inode_unlock(src);
+ return error;
+ }
+ if (src_last)
+ inode_lock_nested(src, I_MUTEX_NONDIR2);
+ return 0;
+}
+
+/*
* Link a range of blocks from one file to another.
*/
int
@@ -1274,7 +1318,9 @@ xfs_reflink_remap_range(
return -EIO;
/* Lock both files against IO */
- lock_two_nondirectories(inode_in, inode_out);
+ ret = xfs_iolock_two_inodes_and_break_layout(inode_in, inode_out);
+ if (ret)
+ return ret;
if (same_inode)
xfs_ilock(src, XFS_MMAPLOCK_EXCL);
else
--
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