Linux: use filemap_range_has_page()

As of the 4.13 kernel filemap_range_has_page() can be used to
check if there is a page mapped in a given file range.  When
available this interface should be used which eliminates the
need for the zp->z_is_mapped boolean.

Reviewed-by: Brian Atkinson <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #14493 

4 files changed, 12 insertions, 5 deletions

diff --git a/module/os/linux/zfs/zfs_ctldir.c b/module/os/linux/zfs/zfs_ctldir.c
index cc4bc9702..dca48e1e4 100644
--- a/module/os/linux/zfs/zfs_ctldir.c
+++ b/module/os/linux/zfs/zfs_ctldir.c
@@ -498,7 +498,9 @@ zfsctl_inode_alloc(zfsvfs_t *zfsvfs, uint64_t id,
 	zp->z_atime_dirty = B_FALSE;
 	zp->z_zn_prefetch = B_FALSE;
 	zp->z_is_sa = B_FALSE;
+#if !defined(HAVE_FILEMAP_RANGE_HAS_PAGE)
 	zp->z_is_mapped = B_FALSE;
+#endif
 	zp->z_is_ctldir = B_TRUE;
 	zp->z_sa_hdl = NULL;
 	zp->z_blksz = 0;
diff --git a/module/os/linux/zfs/zfs_vnops_os.c b/module/os/linux/zfs/zfs_vnops_os.c
index 47f132a38..302a88c2d 100644
--- a/module/os/linux/zfs/zfs_vnops_os.c
+++ b/module/os/linux/zfs/zfs_vnops_os.c
@@ -987,7 +987,7 @@ top:
 
 	mutex_enter(&zp->z_lock);
 	may_delete_now = atomic_read(&ZTOI(zp)->i_count) == 1 &&
-	    !(zp->z_is_mapped);
+	    !zn_has_cached_data(zp, 0, LLONG_MAX);
 	mutex_exit(&zp->z_lock);
 
 	/*
@@ -1075,7 +1075,8 @@ top:
 		    &xattr_obj_unlinked, sizeof (xattr_obj_unlinked));
 		delete_now = may_delete_now && !toobig &&
 		    atomic_read(&ZTOI(zp)->i_count) == 1 &&
-		    !(zp->z_is_mapped) && xattr_obj == xattr_obj_unlinked &&
+		    !zn_has_cached_data(zp, 0, LLONG_MAX) &&
+		    xattr_obj == xattr_obj_unlinked &&
 		    zfs_external_acl(zp) == acl_obj;
 	}
 
diff --git a/module/os/linux/zfs/zfs_znode.c b/module/os/linux/zfs/zfs_znode.c
index 1faf25d93..7b802a9ba 100644
--- a/module/os/linux/zfs/zfs_znode.c
+++ b/module/os/linux/zfs/zfs_znode.c
@@ -551,7 +551,9 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
 	ASSERT3P(zp->z_xattr_cached, ==, NULL);
 	zp->z_unlinked = B_FALSE;
 	zp->z_atime_dirty = B_FALSE;
+#if !defined(HAVE_FILEMAP_RANGE_HAS_PAGE)
 	zp->z_is_mapped = B_FALSE;
+#endif
 	zp->z_is_ctldir = B_FALSE;
 	zp->z_suspended = B_FALSE;
 	zp->z_sa_hdl = NULL;
@@ -1641,7 +1643,7 @@ zfs_free_range(znode_t *zp, uint64_t off, uint64_t len)
 	 * Zero partial page cache entries.  This must be done under a
 	 * range lock in order to keep the ARC and page cache in sync.
 	 */
-	if (zp->z_is_mapped) {
+	if (zn_has_cached_data(zp, off, off + len - 1)) {
 		loff_t first_page, last_page, page_len;
 		loff_t first_page_offset, last_page_offset;
 
diff --git a/module/os/linux/zfs/zpl_file.c b/module/os/linux/zfs/zpl_file.c
index c56e3691e..e42b15042 100644
--- a/module/os/linux/zfs/zpl_file.c
+++ b/module/os/linux/zfs/zpl_file.c
@@ -625,7 +625,6 @@ static int
 zpl_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct inode *ip = filp->f_mapping->host;
-	znode_t *zp = ITOZ(ip);
 	int error;
 	fstrans_cookie_t cookie;
 
@@ -640,9 +639,12 @@ zpl_mmap(struct file *filp, struct vm_area_struct *vma)
 	if (error)
 		return (error);
 
+#if !defined(HAVE_FILEMAP_RANGE_HAS_PAGE)
+	znode_t *zp = ITOZ(ip);
 	mutex_enter(&zp->z_lock);
 	zp->z_is_mapped = B_TRUE;
 	mutex_exit(&zp->z_lock);
+#endif
 
 	return (error);
 }
@@ -937,7 +939,7 @@ zpl_fadvise(struct file *filp, loff_t offset, loff_t len, int advice)
 	case POSIX_FADV_SEQUENTIAL:
 	case POSIX_FADV_WILLNEED:
 #ifdef HAVE_GENERIC_FADVISE
-		if (zn_has_cached_data(zp))
+		if (zn_has_cached_data(zp, offset, offset + len - 1))
 			error = generic_fadvise(filp, offset, len, advice);
 #endif
 		/*