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-rw-r--r--fs/overlayfs/overlayfs.h34
1 files changed, 28 insertions, 6 deletions
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 6934bcf030f0..f283b1d69a9e 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -71,20 +71,36 @@ enum ovl_entry_flag {
#error Endianness not defined
#endif
-/* The type returned by overlay exportfs ops when encoding an ovl_fh handle */
-#define OVL_FILEID 0xfb
+/* The type used to be returned by overlay exportfs for misaligned fid */
+#define OVL_FILEID_V0 0xfb
+/* The type returned by overlay exportfs for 32bit aligned fid */
+#define OVL_FILEID_V1 0xf8
-/* On-disk and in-memeory format for redirect by file handle */
-struct ovl_fh {
+/* On-disk format for "origin" file handle */
+struct ovl_fb {
u8 version; /* 0 */
u8 magic; /* 0xfb */
u8 len; /* size of this header + size of fid */
u8 flags; /* OVL_FH_FLAG_* */
u8 type; /* fid_type of fid */
uuid_t uuid; /* uuid of filesystem */
- u8 fid[0]; /* file identifier */
+ u32 fid[0]; /* file identifier should be 32bit aligned in-memory */
} __packed;
+/* In-memory and on-wire format for overlay file handle */
+struct ovl_fh {
+ u8 padding[3]; /* make sure fb.fid is 32bit aligned */
+ union {
+ struct ovl_fb fb;
+ u8 buf[0];
+ };
+} __packed;
+
+#define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
+#define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
+#define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
+ offsetof(struct ovl_fb, fid))
+
static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
{
int err = vfs_rmdir(dir, dentry);
@@ -302,7 +318,13 @@ static inline void ovl_inode_unlock(struct inode *inode)
/* namei.c */
-int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
+int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
+
+static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
+{
+ return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
+}
+
struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
bool connected);
int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,