xfs: prepare xfs_break_layouts() for another layout type
When xfs is operating as the back-end of a pNFS block server, it
prevents collisions between local and remote operations by requiring a
lease to be held for remotely accessed blocks. Local filesystem
operations break those leases before writing or mutating the extent map
of the file.
A similar mechanism is needed to prevent operations on pinned dax
mappings, like device-DMA, from colliding with extent unmap operations.
BREAK_WRITE and BREAK_UNMAP are introduced as two distinct levels of
layout breaking.
Layouts are broken in the BREAK_WRITE case to ensure that layout-holders
do not collide with local writes. Additionally, layouts are broken in
the BREAK_UNMAP case to make sure the layout-holder has a consistent
view of the file's extent map. While BREAK_WRITE breaks can be satisfied
be recalling FL_LAYOUT leases, BREAK_UNMAP breaks additionally require
waiting for busy dax-pages to go idle while holding XFS_MMAPLOCK_EXCL.
After this refactoring xfs_break_layouts() becomes the entry point for
coordinating both types of breaks. Finally, xfs_break_leased_layouts()
becomes just the BREAK_WRITE handler.
Note that the unlock tracking is needed in a follow on change. That will
coordinate retrying either break handler until both successfully test
for a lease break while maintaining the lock state.
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Reported-by: Dave Chinner <david@fromorbit.com>
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 138fb36..ce0c1f9 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -37,7 +37,6 @@
#include "xfs_da_btree.h"
#include "xfs_dir2.h"
#include "xfs_trans_space.h"
-#include "xfs_pnfs.h"
#include "xfs_iomap.h"
#include <linux/capability.h>
@@ -1030,13 +1029,14 @@ xfs_vn_setattr(
int error;
if (iattr->ia_valid & ATTR_SIZE) {
- struct xfs_inode *ip = XFS_I(d_inode(dentry));
+ struct inode *inode = d_inode(dentry);
+ struct xfs_inode *ip = XFS_I(inode);
uint iolock;
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
- error = xfs_break_layouts(d_inode(dentry), &iolock);
+ error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
if (error) {
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
return error;
