Merge tag 'vfs-6.13.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "Features:

   - Fixup and improve NLM and kNFSD file lock callbacks

     Last year both GFS2 and OCFS2 had some work done to make their
     locking more robust when exported over NFS. Unfortunately, part of
     that work caused both NLM (for NFS v3 exports) and kNFSD (for
     NFSv4.1+ exports) to no longer send lock notifications to clients

     This in itself is not a huge problem because most NFS clients will
     still poll the server in order to acquire a conflicted lock

     It's important for NLM and kNFSD that they do not block their
     kernel threads inside filesystem's file_lock implementations
     because that can produce deadlocks. We used to make sure of this by
     only trusting that posix_lock_file() can correctly handle blocking
     lock calls asynchronously, so the lock managers would only setup
     their file_lock requests for async callbacks if the filesystem did
     not define its own lock() file operation

     However, when GFS2 and OCFS2 grew the capability to correctly
     handle blocking lock requests asynchronously, they started
     signalling this behavior with EXPORT_OP_ASYNC_LOCK, and the check
     for also trusting posix_lock_file() was inadvertently dropped, so
     now most filesystems no longer produce lock notifications when
     exported over NFS

     Fix this by using an fop_flag which greatly simplifies the problem
     and grooms the way for future uses by both filesystems and lock
     managers alike

   - Add a sysctl to delete the dentry when a file is removed instead of
     making it a negative dentry

     Commit 681ce8623567 ("vfs: Delete the associated dentry when
     deleting a file") introduced an unconditional deletion of the
     associated dentry when a file is removed. However, this led to
     performance regressions in specific benchmarks, such as
     ilebench.sum_operations/s, prompting a revert in commit
     4a4be1ad3a6e ("Revert "vfs: Delete the associated dentry when
     deleting a file""). This reintroduces the concept conditionally
     through a sysctl

   - Expand the statmount() system call:

       * Report the filesystem subtype in a new fs_subtype field to
         e.g., report fuse filesystem subtypes

       * Report the superblock source in a new sb_source field

       * Add a new way to return filesystem specific mount options in an
         option array that returns filesystem specific mount options
         separated by zero bytes and unescaped. This allows caller's to
         retrieve filesystem specific mount options and immediately pass
         them to e.g., fsconfig() without having to unescape or split
         them

       * Report security (LSM) specific mount options in a separate
         security option array. We don't lump them together with
         filesystem specific mount options as security mount options are
         generic and most users aren't interested in them

         The format is the same as for the filesystem specific mount
         option array

   - Support relative paths in fsconfig()'s FSCONFIG_SET_STRING command

   - Optimize acl_permission_check() to avoid costly {g,u}id ownership
     checks if possible

   - Use smp_mb__after_spinlock() to avoid full smp_mb() in evict()

   - Add synchronous wakeup support for ep_poll_callback.

     Currently, epoll only uses wake_up() to wake up task. But sometimes
     there are epoll users which want to use the synchronous wakeup flag
     to give a hint to the scheduler, e.g., the Android binder driver.
     So add a wake_up_sync() define, and use wake_up_sync() when sync is
     true in ep_poll_callback()

  Fixes:

   - Fix kernel documentation for inode_insert5() and iget5_locked()

   - Annotate racy epoll check on file->f_ep

   - Make F_DUPFD_QUERY associative

   - Avoid filename buffer overrun in initramfs

   - Don't let statmount() return empty strings

   - Add a cond_resched() to dump_user_range() to avoid hogging the CPU

   - Don't query the device logical blocksize multiple times for hfsplus

   - Make filemap_read() check that the offset is positive or zero

  Cleanups:

   - Various typo fixes

   - Cleanup wbc_attach_fdatawrite_inode()

   - Add __releases annotation to wbc_attach_and_unlock_inode()

   - Add hugetlbfs tracepoints

   - Fix various vfs kernel doc parameters

   - Remove obsolete TODO comment from io_cancel()

   - Convert wbc_account_cgroup_owner() to take a folio

   - Fix comments for BANDWITH_INTERVAL and wb_domain_writeout_add()

   - Reorder struct posix_acl to save 8 bytes

   - Annotate struct posix_acl with __counted_by()

   - Replace one-element array with flexible array member in freevxfs

   - Use idiomatic atomic64_inc_return() in alloc_mnt_ns()"

* tag 'vfs-6.13.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
  statmount: retrieve security mount options
  vfs: make evict() use smp_mb__after_spinlock instead of smp_mb
  statmount: add flag to retrieve unescaped options
  fs: add the ability for statmount() to report the sb_source
  writeback: wbc_attach_fdatawrite_inode out of line
  writeback: add a __releases annoation to wbc_attach_and_unlock_inode
  fs: add the ability for statmount() to report the fs_subtype
  fs: don't let statmount return empty strings
  fs:aio: Remove TODO comment suggesting hash or array usage in io_cancel()
  hfsplus: don't query the device logical block size multiple times
  freevxfs: Replace one-element array with flexible array member
  fs: optimize acl_permission_check()
  initramfs: avoid filename buffer overrun
  fs/writeback: convert wbc_account_cgroup_owner to take a folio
  acl: Annotate struct posix_acl with __counted_by()
  acl: Realign struct posix_acl to save 8 bytes
  epoll: Add synchronous wakeup support for ep_poll_callback
  coredump: add cond_resched() to dump_user_range
  mm/page-writeback.c: Fix comment of wb_domain_writeout_add()
  mm/page-writeback.c: Update comment for BANDWIDTH_INTERVAL
  ...

1 files changed, 154 insertions, 7 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index d26f5e6d2ca3..206fc54feeba 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3901,7 +3901,7 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a
 	}
 	new_ns->ns.ops = &mntns_operations;
 	if (!anon)
-		new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
+		new_ns->seq = atomic64_inc_return(&mnt_ns_seq);
 	refcount_set(&new_ns->ns.count, 1);
 	refcount_set(&new_ns->passive, 1);
 	new_ns->mounts = RB_ROOT;
@@ -5006,6 +5006,40 @@ static int statmount_fs_type(struct kstatmount *s, struct seq_file *seq)
 	return 0;
 }
 
+static void statmount_fs_subtype(struct kstatmount *s, struct seq_file *seq)
+{
+	struct super_block *sb = s->mnt->mnt_sb;
+
+	if (sb->s_subtype)
+		seq_puts(seq, sb->s_subtype);
+}
+
+static int statmount_sb_source(struct kstatmount *s, struct seq_file *seq)
+{
+	struct super_block *sb = s->mnt->mnt_sb;
+	struct mount *r = real_mount(s->mnt);
+
+	if (sb->s_op->show_devname) {
+		size_t start = seq->count;
+		int ret;
+
+		ret = sb->s_op->show_devname(seq, s->mnt->mnt_root);
+		if (ret)
+			return ret;
+
+		if (unlikely(seq_has_overflowed(seq)))
+			return -EAGAIN;
+
+		/* Unescape the result */
+		seq->buf[seq->count] = '\0';
+		seq->count = start;
+		seq_commit(seq, string_unescape_inplace(seq->buf + start, UNESCAPE_OCTAL));
+	} else if (r->mnt_devname) {
+		seq_puts(seq, r->mnt_devname);
+	}
+	return 0;
+}
+
 static void statmount_mnt_ns_id(struct kstatmount *s, struct mnt_namespace *ns)
 {
 	s->sm.mask |= STATMOUNT_MNT_NS_ID;
@@ -5040,35 +5074,134 @@ static int statmount_mnt_opts(struct kstatmount *s, struct seq_file *seq)
 	return 0;
 }
 
+static inline int statmount_opt_unescape(struct seq_file *seq, char *buf_start)
+{
+	char *buf_end, *opt_start, *opt_end;
+	int count = 0;
+
+	buf_end = seq->buf + seq->count;
+	*buf_end = '\0';
+	for (opt_start = buf_start + 1; opt_start < buf_end; opt_start = opt_end + 1) {
+		opt_end = strchrnul(opt_start, ',');
+		*opt_end = '\0';
+		buf_start += string_unescape(opt_start, buf_start, 0, UNESCAPE_OCTAL) + 1;
+		if (WARN_ON_ONCE(++count == INT_MAX))
+			return -EOVERFLOW;
+	}
+	seq->count = buf_start - 1 - seq->buf;
+	return count;
+}
+
+static int statmount_opt_array(struct kstatmount *s, struct seq_file *seq)
+{
+	struct vfsmount *mnt = s->mnt;
+	struct super_block *sb = mnt->mnt_sb;
+	size_t start = seq->count;
+	char *buf_start;
+	int err;
+
+	if (!sb->s_op->show_options)
+		return 0;
+
+	buf_start = seq->buf + start;
+	err = sb->s_op->show_options(seq, mnt->mnt_root);
+	if (err)
+		return err;
+
+	if (unlikely(seq_has_overflowed(seq)))
+		return -EAGAIN;
+
+	if (seq->count == start)
+		return 0;
+
+	err = statmount_opt_unescape(seq, buf_start);
+	if (err < 0)
+		return err;
+
+	s->sm.opt_num = err;
+	return 0;
+}
+
+static int statmount_opt_sec_array(struct kstatmount *s, struct seq_file *seq)
+{
+	struct vfsmount *mnt = s->mnt;
+	struct super_block *sb = mnt->mnt_sb;
+	size_t start = seq->count;
+	char *buf_start;
+	int err;
+
+	buf_start = seq->buf + start;
+
+	err = security_sb_show_options(seq, sb);
+	if (!err)
+		return err;
+
+	if (unlikely(seq_has_overflowed(seq)))
+		return -EAGAIN;
+
+	if (seq->count == start)
+		return 0;
+
+	err = statmount_opt_unescape(seq, buf_start);
+	if (err < 0)
+		return err;
+
+	s->sm.opt_sec_num = err;
+	return 0;
+}
+
 static int statmount_string(struct kstatmount *s, u64 flag)
 {
-	int ret;
+	int ret = 0;
 	size_t kbufsize;
 	struct seq_file *seq = &s->seq;
 	struct statmount *sm = &s->sm;
+	u32 start = seq->count;
 
 	switch (flag) {
 	case STATMOUNT_FS_TYPE:
-		sm->fs_type = seq->count;
+		sm->fs_type = start;
 		ret = statmount_fs_type(s, seq);
 		break;
 	case STATMOUNT_MNT_ROOT:
-		sm->mnt_root = seq->count;
+		sm->mnt_root = start;
 		ret = statmount_mnt_root(s, seq);
 		break;
 	case STATMOUNT_MNT_POINT:
-		sm->mnt_point = seq->count;
+		sm->mnt_point = start;
 		ret = statmount_mnt_point(s, seq);
 		break;
 	case STATMOUNT_MNT_OPTS:
-		sm->mnt_opts = seq->count;
+		sm->mnt_opts = start;
 		ret = statmount_mnt_opts(s, seq);
 		break;
+	case STATMOUNT_OPT_ARRAY:
+		sm->opt_array = start;
+		ret = statmount_opt_array(s, seq);
+		break;
+	case STATMOUNT_OPT_SEC_ARRAY:
+		sm->opt_sec_array = start;
+		ret = statmount_opt_sec_array(s, seq);
+		break;
+	case STATMOUNT_FS_SUBTYPE:
+		sm->fs_subtype = start;
+		statmount_fs_subtype(s, seq);
+		break;
+	case STATMOUNT_SB_SOURCE:
+		sm->sb_source = start;
+		ret = statmount_sb_source(s, seq);
+		break;
 	default:
 		WARN_ON_ONCE(true);
 		return -EINVAL;
 	}
 
+	/*
+	 * If nothing was emitted, return to avoid setting the flag
+	 * and terminating the buffer.
+	 */
+	if (seq->count == start)
+		return ret;
 	if (unlikely(check_add_overflow(sizeof(*sm), seq->count, &kbufsize)))
 		return -EOVERFLOW;
 	if (kbufsize >= s->bufsize)
@@ -5203,6 +5336,18 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
 	if (!err && s->mask & STATMOUNT_MNT_OPTS)
 		err = statmount_string(s, STATMOUNT_MNT_OPTS);
 
+	if (!err && s->mask & STATMOUNT_OPT_ARRAY)
+		err = statmount_string(s, STATMOUNT_OPT_ARRAY);
+
+	if (!err && s->mask & STATMOUNT_OPT_SEC_ARRAY)
+		err = statmount_string(s, STATMOUNT_OPT_SEC_ARRAY);
+
+	if (!err && s->mask & STATMOUNT_FS_SUBTYPE)
+		err = statmount_string(s, STATMOUNT_FS_SUBTYPE);
+
+	if (!err && s->mask & STATMOUNT_SB_SOURCE)
+		err = statmount_string(s, STATMOUNT_SB_SOURCE);
+
 	if (!err && s->mask & STATMOUNT_MNT_NS_ID)
 		statmount_mnt_ns_id(s, ns);
 
@@ -5224,7 +5369,9 @@ static inline bool retry_statmount(const long ret, size_t *seq_size)
 }
 
 #define STATMOUNT_STRING_REQ (STATMOUNT_MNT_ROOT | STATMOUNT_MNT_POINT | \
-			      STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS)
+			      STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS | \
+			      STATMOUNT_FS_SUBTYPE | STATMOUNT_SB_SOURCE | \
+			      STATMOUNT_OPT_ARRAY | STATMOUNT_OPT_SEC_ARRAY)
 
 static int prepare_kstatmount(struct kstatmount *ks, struct mnt_id_req *kreq,
 			      struct statmount __user *buf, size_t bufsize,