xfs: unlock i_mutex in xfs_break_layouts

We want to drop all I/O path locks when recalling layouts, and that includes
i_mutex for the write path.  Without this we get stuck processe when recalls
take too long.

[dchinner: fix build with !CONFIG_PNFS]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_file.c

@@ -555,7 +555,7 @@ restart:
 	if (error)
 		return error;
 
-	error = xfs_break_layouts(inode, iolock);
+	error = xfs_break_layouts(inode, iolock, true);
 	if (error)
 		return error;
 
@@ -842,7 +842,7 @@ xfs_file_fallocate(
 		return -EOPNOTSUPP;
 
 	xfs_ilock(ip, iolock);
-	error = xfs_break_layouts(inode, &iolock);
+	error = xfs_break_layouts(inode, &iolock, false);
 	if (error)
 		goto out_unlock;
 

fs/xfs/xfs_ioctl.c

@@ -639,7 +639,7 @@ xfs_ioc_space(
 		return error;
 
 	xfs_ilock(ip, iolock);
-	error = xfs_break_layouts(inode, &iolock);
+	error = xfs_break_layouts(inode, &iolock, false);
 	if (error)
 		goto out_unlock;
 

fs/xfs/xfs_iops.c

@@ -988,7 +988,7 @@ xfs_vn_setattr(
 		uint		iolock = XFS_IOLOCK_EXCL;
 
 		xfs_ilock(ip, iolock);
-		error = xfs_break_layouts(dentry->d_inode, &iolock);
+		error = xfs_break_layouts(dentry->d_inode, &iolock, true);
 		if (!error)
 			error = xfs_setattr_size(ip, iattr);
 		xfs_iunlock(ip, iolock);

fs/xfs/xfs_pnfs.c

@@ -31,7 +31,8 @@
 int
 xfs_break_layouts(
 	struct inode		*inode,
-	uint			*iolock)
+	uint			*iolock,
+	bool			with_imutex)
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 	int			error;
@@ -40,8 +41,12 @@ xfs_break_layouts(
 
 	while ((error = break_layout(inode, false) == -EWOULDBLOCK)) {
 		xfs_iunlock(ip, *iolock);
+		if (with_imutex && (*iolock & XFS_IOLOCK_EXCL))
+			mutex_unlock(&inode->i_mutex);
 		error = break_layout(inode, true);
 		*iolock = XFS_IOLOCK_EXCL;
+		if (with_imutex)
+			mutex_lock(&inode->i_mutex);
 		xfs_ilock(ip, *iolock);
 	}
 

fs/xfs/xfs_pnfs.h

@@ -8,9 +8,10 @@ int xfs_fs_map_blocks(struct inode *inode, loff_t offset, u64 length,
 int xfs_fs_commit_blocks(struct inode *inode, struct iomap *maps, int nr_maps,
 		struct iattr *iattr);
 
-int xfs_break_layouts(struct inode *inode, uint *iolock);
+int xfs_break_layouts(struct inode *inode, uint *iolock, bool with_imutex);
 #else
-static inline int xfs_break_layouts(struct inode *inode, uint *iolock)
+static inline int
+xfs_break_layouts(struct inode *inode, uint *iolock, bool with_imutex)
 {
 	return 0;
 }