From 9d008240e684ea13b35b107589f354a266aca850 Mon Sep 17 00:00:00 2001

From: Peter Georg <peter.georg@physik.uni-regensburg.de>

Date: Wed, 22 Sep 2021 22:32:42 +0200

Subject: [PATCH 9005/9005] Compat: Add fiemap_prep function

---

 src/compat.h | 43 +++++++++++++++++++++++++++++++++++++++++++

 src/file.c   |  2 ++

 2 files changed, 45 insertions(+)

 create mode 100644 src/compat.h

diff --git a/src/compat.h b/src/compat.h

new file mode 100644

index 0000000..9862d76

--- /dev/null

+++ b/src/compat.h

@@ -0,0 +1,43 @@

+ /**

+ * fiemap_prep - check validity of requested flags for fiemap

+ * @inode:	Inode to operate on

+ * @fieinfo:	Fiemap context passed into ->fiemap

+ * @start:	Start of the mapped range

+ * @len:	Length of the mapped range, can be truncated by this function.

+ * @supported_flags:	Set of fiemap flags that the file system understands

+ *

+ * This function must be called from each ->fiemap instance to validate the

+ * fiemap request against the file system parameters.

+ *

+ * Returns 0 on success, or a negative error on failure.

+ */

+static int fiemap_prep(struct inode *inode, struct fiemap_extent_info *fieinfo,

+		u64 start, u64 *len, u32 supported_flags)

+{

+	u64 maxbytes = inode->i_sb->s_maxbytes;

+	u32 incompat_flags;

+	int ret = 0;

+

+	if (*len == 0)

+		return -EINVAL;

+	if (start > maxbytes)

+		return -EFBIG;

+

+	/*

+	 * Shrink request scope to what the fs can actually handle.

+	 */

+	if (*len > maxbytes || (maxbytes - *len) < start)

+		*len = maxbytes - start;

+

+	supported_flags |= FIEMAP_FLAG_SYNC;

+	supported_flags &= FIEMAP_FLAGS_COMPAT;

+	incompat_flags = fieinfo->fi_flags & ~supported_flags;

+	if (incompat_flags) {

+		fieinfo->fi_flags = incompat_flags;

+		return -EBADR;

+	}

+

+	if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)

+		ret = filemap_write_and_wait(inode->i_mapping);

+	return ret;

+}

diff --git a/src/file.c b/src/file.c

index d89afcd..d72800c 100644

--- a/src/file.c

+++ b/src/file.c

@@ -17,6 +17,8 @@

 #include "ntfs.h"

 #include "ntfs_fs.h"

+#include "compat.h"

+

 static int ntfs_ioctl_fitrim(struct ntfs_sb_info *sbi, unsigned long arg)

 {

 	struct fstrim_range __user *user_range;

-- 

2.31.1