Merge tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fanotify fsid updates from Christian Brauner:
 "This work is part of the plan to enable fanotify to serve as a drop-in
  replacement for inotify. While inotify is availabe on all filesystems,
  fanotify currently isn't.

  In order to support fanotify on all filesystems two things are needed:

   (1) all filesystems need to support AT_HANDLE_FID

   (2) all filesystems need to report a non-zero f_fsid

  This contains (1) and allows filesystems to encode non-decodable file
  handlers for fanotify without implementing any exportfs operations by
  encoding a file id of type FILEID_INO64_GEN from i_ino and
  i_generation.

  Filesystems that want to opt out of encoding non-decodable file ids
  for fanotify that don't support NFS export can do so by providing an
  empty export_operations struct.

  This also partially addresses (2) by generating f_fsid for simple
  filesystems as well as freevxfs. Remaining filesystems will be dealt
  with by separate patches.

  Finally, this contains the patch from the current exportfs maintainers
  which moves exportfs under vfs with Chuck, Jeff, and Amir as
  maintainers and vfs.git as tree"

* tag 'vfs-6.7.fsid' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  MAINTAINERS: create an entry for exportfs
  fs: fix build error with CONFIG_EXPORTFS=m or not defined
  freevxfs: derive f_fsid from bdev->bd_dev
  fs: report f_fsid from s_dev for "simple" filesystems
  exportfs: support encoding non-decodeable file handles by default
  exportfs: define FILEID_INO64_GEN* file handle types
  exportfs: make ->encode_fh() a mandatory method for NFS export
  exportfs: add helpers to check if filesystem can encode/decode file handles

1 files changed, 47 insertions, 3 deletions

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 0388e8c20f52..bb37ad5cc954 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -99,6 +99,17 @@ enum fid_type {
 	FILEID_FAT_WITH_PARENT = 0x72,
 
 	/*
+	 * 64 bit inode number, 32 bit generation number.
+	 */
+	FILEID_INO64_GEN = 0x81,
+
+	/*
+	 * 64 bit inode number, 32 bit generation number,
+	 * 64 bit parent inode number, 32 bit parent generation.
+	 */
+	FILEID_INO64_GEN_PARENT = 0x82,
+
+	/*
 	 * 128 bit child FID (struct lu_fid)
 	 * 128 bit parent FID (struct lu_fid)
 	 */
@@ -129,7 +140,11 @@ struct fid {
 			u32 parent_ino;
 			u32 parent_gen;
 		} i32;
- 		struct {
+		struct {
+			u64 ino;
+			u32 gen;
+		} __packed i64;
+		struct {
  			u32 block;
  			u16 partref;
  			u16 parent_partref;
@@ -253,6 +268,33 @@ extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
 			      int *max_len, int flags);
 
+static inline bool exportfs_can_encode_fid(const struct export_operations *nop)
+{
+	return !nop || nop->encode_fh;
+}
+
+static inline bool exportfs_can_decode_fh(const struct export_operations *nop)
+{
+	return nop && nop->fh_to_dentry;
+}
+
+static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
+					  int fh_flags)
+{
+	/*
+	 * If a non-decodeable file handle was requested, we only need to make
+	 * sure that filesystem did not opt-out of encoding fid.
+	 */
+	if (fh_flags & EXPORT_FH_FID)
+		return exportfs_can_encode_fid(nop);
+
+	/*
+	 * If a decodeable file handle was requested, we need to make sure that
+	 * filesystem can also decode file handles.
+	 */
+	return exportfs_can_decode_fh(nop);
+}
+
 static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid,
 				      int *max_len)
 {
@@ -272,10 +314,12 @@ extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 /*
  * Generic helpers for filesystems.
  */
-extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
+int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len,
+			    struct inode *parent);
+struct dentry *generic_fh_to_dentry(struct super_block *sb,
 	struct fid *fid, int fh_len, int fh_type,
 	struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
-extern struct dentry *generic_fh_to_parent(struct super_block *sb,
+struct dentry *generic_fh_to_parent(struct super_block *sb,
 	struct fid *fid, int fh_len, int fh_type,
 	struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));