Merge tag 'vfs-6.19-rc1.directory.delegations' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull directory delegations update from Christian Brauner:
 "This contains the work for recall-only directory delegations for
  knfsd.

  Add support for simple, recallable-only directory delegations. This
  was decided at the fall NFS Bakeathon where the NFS client and server
  maintainers discussed how to merge directory delegation support.

  The approach starts with recallable-only delegations for several reasons:

   1. RFC8881 has gaps that are being addressed in RFC8881bis. In
      particular, it requires directory position information for
      CB_NOTIFY callbacks, which is difficult to implement properly
      under Linux. The spec is being extended to allow that information
      to be omitted.

   2. Client-side support for CB_NOTIFY still lags. The client side
      involves heuristics about when to request a delegation.

   3. Early indication shows simple, recallable-only delegations can
      help performance. Anna Schumaker mentioned seeing a multi-minute
      speedup in xfstests runs with them enabled.

  With these changes, userspace can also request a read lease on a
  directory that will be recalled on conflicting accesses. This may be
  useful for applications like Samba. Users can disable leases
  altogether via the fs.leases-enable sysctl if needed.

  VFS changes:

   - Dedicated Type for Delegations

     Introduce struct delegated_inode to track inodes that may have
     delegations that need to be broken. This replaces the previous
     approach of passing raw inode pointers through the delegation
     breaking code paths, providing better type safety and clearer
     semantics for the delegation machinery.

   - Break parent directory delegations in open(..., O_CREAT) codepath

   - Allow mkdir to wait for delegation break on parent

   - Allow rmdir to wait for delegation break on parent

   - Add try_break_deleg calls for parents to vfs_link(), vfs_rename(),
     and vfs_unlink()

   - Make vfs_create(), vfs_mknod(), and vfs_symlink() break delegations
     on parent directory

   - Clean up argument list for vfs_create()

   - Expose delegation support to userland

  Filelock changes:

   - Make lease_alloc() take a flags argument

   - Rework the __break_lease API to use flags

   - Add struct delegated_inode

   - Push the S_ISREG check down to ->setlease handlers

   - Lift the ban on directory leases in generic_setlease

  NFSD changes:

   - Allow filecache to hold S_IFDIR files

   - Allow DELEGRETURN on directories

   - Wire up GET_DIR_DELEGATION handling

  Fixes:

   - Fix kernel-doc warnings in __fcntl_getlease

   - Add needed headers for new struct delegation definition"

* tag 'vfs-6.19-rc1.directory.delegations' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  vfs: add needed headers for new struct delegation definition
  filelock: __fcntl_getlease: fix kernel-doc warnings
  vfs: expose delegation support to userland
  nfsd: wire up GET_DIR_DELEGATION handling
  nfsd: allow DELEGRETURN on directories
  nfsd: allow filecache to hold S_IFDIR files
  filelock: lift the ban on directory leases in generic_setlease
  vfs: make vfs_symlink break delegations on parent dir
  vfs: make vfs_mknod break delegations on parent directory
  vfs: make vfs_create break delegations on parent directory
  vfs: clean up argument list for vfs_create()
  vfs: break parent dir delegations in open(..., O_CREAT) codepath
  vfs: allow rmdir to wait for delegation break on parent
  vfs: allow mkdir to wait for delegation break on parent
  vfs: add try_break_deleg calls for parents to vfs_{link,rename,unlink}
  filelock: push the S_ISREG check down to ->setlease handlers
  filelock: add struct delegated_inode
  filelock: rework the __break_lease API to use flags
  filelock: make lease_alloc() take a flags argument

1 files changed, 77 insertions, 26 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 04a3f0e20724..9f565802a88c 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -585,7 +585,7 @@ static const struct lease_manager_operations lease_manager_ops = {
 /*
  * Initialize a lease, use the default lock manager operations
  */
-static int lease_init(struct file *filp, int type, struct file_lease *fl)
+static int lease_init(struct file *filp, unsigned int flags, int type, struct file_lease *fl)
 {
 	if (assign_type(&fl->c, type) != 0)
 		return -EINVAL;
@@ -594,13 +594,13 @@ static int lease_init(struct file *filp, int type, struct file_lease *fl)
 	fl->c.flc_pid = current->tgid;
 
 	fl->c.flc_file = filp;
-	fl->c.flc_flags = FL_LEASE;
+	fl->c.flc_flags = flags;
 	fl->fl_lmops = &lease_manager_ops;
 	return 0;
 }
 
 /* Allocate a file_lock initialised to this type of lease */
-static struct file_lease *lease_alloc(struct file *filp, int type)
+static struct file_lease *lease_alloc(struct file *filp, unsigned int flags, int type)
 {
 	struct file_lease *fl = locks_alloc_lease();
 	int error = -ENOMEM;
@@ -608,7 +608,7 @@ static struct file_lease *lease_alloc(struct file *filp, int type)
 	if (fl == NULL)
 		return ERR_PTR(error);
 
-	error = lease_init(filp, type, fl);
+	error = lease_init(filp, flags, type, fl);
 	if (error) {
 		locks_free_lease(fl);
 		return ERR_PTR(error);
@@ -1529,29 +1529,35 @@ any_leases_conflict(struct inode *inode, struct file_lease *breaker)
 /**
  *	__break_lease	-	revoke all outstanding leases on file
  *	@inode: the inode of the file to return
- *	@mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
- *	    break all leases
- *	@type: FL_LEASE: break leases and delegations; FL_DELEG: break
- *	    only delegations
+ *	@flags: LEASE_BREAK_* flags
  *
  *	break_lease (inlined for speed) has checked there already is at least
  *	some kind of lock (maybe a lease) on this file.  Leases are broken on
- *	a call to open() or truncate().  This function can sleep unless you
- *	specified %O_NONBLOCK to your open().
+ *	a call to open() or truncate().  This function can block waiting for the
+ *	lease break unless you specify LEASE_BREAK_NONBLOCK.
  */
-int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
+int __break_lease(struct inode *inode, unsigned int flags)
 {
-	int error = 0;
-	struct file_lock_context *ctx;
 	struct file_lease *new_fl, *fl, *tmp;
+	struct file_lock_context *ctx;
 	unsigned long break_time;
-	int want_write = (mode & O_ACCMODE) != O_RDONLY;
+	unsigned int type;
 	LIST_HEAD(dispose);
+	bool want_write = !(flags & LEASE_BREAK_OPEN_RDONLY);
+	int error = 0;
 
-	new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
+	if (flags & LEASE_BREAK_LEASE)
+		type = FL_LEASE;
+	else if (flags & LEASE_BREAK_DELEG)
+		type = FL_DELEG;
+	else if (flags & LEASE_BREAK_LAYOUT)
+		type = FL_LAYOUT;
+	else
+		return -EINVAL;
+
+	new_fl = lease_alloc(NULL, type, want_write ? F_WRLCK : F_RDLCK);
 	if (IS_ERR(new_fl))
 		return PTR_ERR(new_fl);
-	new_fl->c.flc_flags = type;
 
 	/* typically we will check that ctx is non-NULL before calling */
 	ctx = locks_inode_context(inode);
@@ -1596,7 +1602,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 	if (list_empty(&ctx->flc_lease))
 		goto out;
 
-	if (mode & O_NONBLOCK) {
+	if (flags & LEASE_BREAK_NONBLOCK) {
 		trace_break_lease_noblock(inode, new_fl);
 		error = -EWOULDBLOCK;
 		goto out;
@@ -1675,8 +1681,9 @@ void lease_get_mtime(struct inode *inode, struct timespec64 *time)
 EXPORT_SYMBOL(lease_get_mtime);
 
 /**
- *	fcntl_getlease - Enquire what lease is currently active
+ *	__fcntl_getlease - Enquire what lease is currently active
  *	@filp: the file
+ *	@flavor: type of lease flags to check
  *
  *	The value returned by this function will be one of
  *	(if no lease break is pending):
@@ -1697,7 +1704,7 @@ EXPORT_SYMBOL(lease_get_mtime);
  *	XXX: sfr & willy disagree over whether F_INPROGRESS
  *	should be returned to userspace.
  */
-int fcntl_getlease(struct file *filp)
+static int __fcntl_getlease(struct file *filp, unsigned int flavor)
 {
 	struct file_lease *fl;
 	struct inode *inode = file_inode(filp);
@@ -1713,7 +1720,8 @@ int fcntl_getlease(struct file *filp)
 		list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) {
 			if (fl->c.flc_file != filp)
 				continue;
-			type = target_leasetype(fl);
+			if (fl->c.flc_flags & flavor)
+				type = target_leasetype(fl);
 			break;
 		}
 		spin_unlock(&ctx->flc_lock);
@@ -1724,6 +1732,19 @@ int fcntl_getlease(struct file *filp)
 	return type;
 }
 
+int fcntl_getlease(struct file *filp)
+{
+	return __fcntl_getlease(filp, FL_LEASE);
+}
+
+int fcntl_getdeleg(struct file *filp, struct delegation *deleg)
+{
+	if (deleg->d_flags != 0 || deleg->__pad != 0)
+		return -EINVAL;
+	deleg->d_type = __fcntl_getlease(filp, FL_DELEG);
+	return 0;
+}
+
 /**
  * check_conflicting_open - see if the given file points to an inode that has
  *			    an existing open that would conflict with the
@@ -1929,11 +1950,19 @@ static int generic_delete_lease(struct file *filp, void *owner)
 int generic_setlease(struct file *filp, int arg, struct file_lease **flp,
 			void **priv)
 {
+	struct inode *inode = file_inode(filp);
+
+	if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
+		return -EINVAL;
+
 	switch (arg) {
 	case F_UNLCK:
 		return generic_delete_lease(filp, *priv);
-	case F_RDLCK:
 	case F_WRLCK:
+		if (S_ISDIR(inode->i_mode))
+			return -EINVAL;
+		fallthrough;
+	case F_RDLCK:
 		if (!(*flp)->fl_lmops->lm_break) {
 			WARN_ON_ONCE(1);
 			return -ENOLCK;
@@ -2018,8 +2047,6 @@ vfs_setlease(struct file *filp, int arg, struct file_lease **lease, void **priv)
 
 	if ((!vfsuid_eq_kuid(vfsuid, current_fsuid())) && !capable(CAP_LEASE))
 		return -EACCES;
-	if (!S_ISREG(inode->i_mode))
-		return -EINVAL;
 	error = security_file_lock(filp, arg);
 	if (error)
 		return error;
@@ -2027,13 +2054,13 @@ vfs_setlease(struct file *filp, int arg, struct file_lease **lease, void **priv)
 }
 EXPORT_SYMBOL_GPL(vfs_setlease);
 
-static int do_fcntl_add_lease(unsigned int fd, struct file *filp, int arg)
+static int do_fcntl_add_lease(unsigned int fd, struct file *filp, unsigned int flavor, int arg)
 {
 	struct file_lease *fl;
 	struct fasync_struct *new;
 	int error;
 
-	fl = lease_alloc(filp, arg);
+	fl = lease_alloc(filp, flavor, arg);
 	if (IS_ERR(fl))
 		return PTR_ERR(fl);
 
@@ -2064,9 +2091,33 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, int arg)
  */
 int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
 {
+	if (S_ISDIR(file_inode(filp)->i_mode))
+		return -EINVAL;
+
 	if (arg == F_UNLCK)
 		return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
-	return do_fcntl_add_lease(fd, filp, arg);
+	return do_fcntl_add_lease(fd, filp, FL_LEASE, arg);
+}
+
+/**
+ *	fcntl_setdeleg	-	sets a delegation on an open file
+ *	@fd: open file descriptor
+ *	@filp: file pointer
+ *	@deleg: delegation request from userland
+ *
+ *	Call this fcntl to establish a delegation on the file.
+ *	Note that you also need to call %F_SETSIG to
+ *	receive a signal when the lease is broken.
+ */
+int fcntl_setdeleg(unsigned int fd, struct file *filp, struct delegation *deleg)
+{
+	/* For now, no flags are supported */
+	if (deleg->d_flags != 0 || deleg->__pad != 0)
+		return -EINVAL;
+
+	if (deleg->d_type == F_UNLCK)
+		return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
+	return do_fcntl_add_lease(fd, filp, FL_DELEG, deleg->d_type);
 }
 
 /**