Now when everything is prepared, add support in ext4 to accept MAP_SYNC
as an mmap(2) flag.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext4/file.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 61a8788168f3..f013cda84b3d 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -364,6 +364,25 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
return 0;
}
+#define EXT4_SUPPORTED_MAP_FLAGS (LEGACY_MAP_MASK | MAP_SYNC)
+
+static int ext4_file_mmap_validate(struct file *file,
+ struct vm_area_struct *vma,
+ unsigned long map_flags)
+{
+ if (map_flags & ~EXT4_SUPPORTED_MAP_FLAGS)
+ return -EOPNOTSUPP;
+
+ /*
+ * We don't support synchronous mappings for non-DAX files. At least
+ * until someone comes with a sensible use case.
+ */
+ if (!IS_DAX(file_inode(file)) && (map_flags & MAP_SYNC))
+ return -EOPNOTSUPP;
+
+ return ext4_file_mmap(file, vma);
+}
+
static int ext4_file_open(struct inode * inode, struct file * filp)
{
struct super_block *sb = inode->i_sb;
@@ -723,6 +742,7 @@ const struct file_operations ext4_file_operations = {
.compat_ioctl = ext4_compat_ioctl,
#endif
.mmap = ext4_file_mmap,
+ .mmap_validate = ext4_file_mmap_validate,
.open = ext4_file_open,
.release = ext4_release_file,
.fsync = ext4_sync_file,
--
2.12.3
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