Merge tag 'gfs2-v6.7-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 updates from Andreas Gruenbacher:

 - Add support for non-blocking lookup (MAY_NOT_BLOCK / LOOKUP_RCU)

 - Various minor fixes and cleanups

* tag 'gfs2-v6.7-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix freeze consistency check in log_write_header
  gfs2: Refcounting fix in gfs2_thaw_super
  gfs2: Minor gfs2_{freeze,thaw}_super cleanup
  gfs2: Use wait_event_freezable_timeout() for freezable kthread
  gfs2: Add missing set_freezable() for freezable kthread
  gfs2: Remove use of error flag in journal reads
  gfs2: Lift withdraw check out of gfs2_ail1_empty
  gfs2: Rename gfs2_withdrawn to gfs2_withdrawing_or_withdrawn
  gfs2: Mark withdraws as unlikely
  gfs2: Minor gfs2_ail1_empty cleanup
  gfs2: use is_subdir()
  gfs2: d_obtain_alias(ERR_PTR(...)) will do the right thing
  gfs2: Use GL_NOBLOCK flag for non-blocking lookups
  gfs2: Add GL_NOBLOCK flag
  gfs2: rgrp: fix kernel-doc warnings
  gfs2: fix kernel BUG in gfs2_quota_cleanup
  gfs2: Fix inode_go_instantiate description
  gfs2: Fix kernel NULL pointer dereference in gfs2_rgrp_dump

Author: torvalds

fs/gfs2/aops.c

@@ -459,7 +459,7 @@ static int gfs2_read_folio(struct file *file, struct folio *folio)
 		error = mpage_read_folio(folio, gfs2_block_map);
 	}
 
-	if (unlikely(gfs2_withdrawn(sdp)))
+	if (gfs2_withdrawing_or_withdrawn(sdp))
 		return -EIO;
 
 	return error;

fs/gfs2/dentry.c

@@ -32,21 +32,25 @@
 
 static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
 {
-	struct dentry *parent;
+	struct dentry *parent = NULL;
 	struct gfs2_sbd *sdp;
 	struct gfs2_inode *dip;
-	struct inode *inode;
+	struct inode *dinode, *inode;
 	struct gfs2_holder d_gh;
 	struct gfs2_inode *ip = NULL;
 	int error, valid = 0;
 	int had_lock = 0;
 
-	if (flags & LOOKUP_RCU)
-		return -ECHILD;
-
-	parent = dget_parent(dentry);
-	sdp = GFS2_SB(d_inode(parent));
-	dip = GFS2_I(d_inode(parent));
+	if (flags & LOOKUP_RCU) {
+		dinode = d_inode_rcu(READ_ONCE(dentry->d_parent));
+		if (!dinode)
+			return -ECHILD;
+	} else {
+		parent = dget_parent(dentry);
+		dinode = d_inode(parent);
+	}
+	sdp = GFS2_SB(dinode);
+	dip = GFS2_I(dinode);
 	inode = d_inode(dentry);
 
 	if (inode) {
@@ -62,7 +66,8 @@ static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
 
 	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
 	if (!had_lock) {
-		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
+		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED,
+					   flags & LOOKUP_RCU ? GL_NOBLOCK : 0, &d_gh);
 		if (error)
 			goto out;
 	}

fs/gfs2/export.c

@@ -138,8 +138,6 @@ static struct dentry *gfs2_get_dentry(struct super_block *sb,
 		return ERR_PTR(-ESTALE);
 	inode = gfs2_lookup_by_inum(sdp, inum->no_addr, inum->no_formal_ino,
 				    GFS2_BLKST_DINODE);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
 	return d_obtain_alias(inode);
 }
 

fs/gfs2/file.c

@@ -1442,7 +1442,7 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
 
 	if (!(fl->fl_flags & FL_POSIX))
 		return -ENOLCK;
-	if (unlikely(gfs2_withdrawn(sdp))) {
+	if (gfs2_withdrawing_or_withdrawn(sdp)) {
 		if (fl->fl_type == F_UNLCK)
 			locks_lock_file_wait(file, fl);
 		return -EIO;

fs/gfs2/glock.c

@@ -156,7 +156,7 @@ static bool glock_blocked_by_withdraw(struct gfs2_glock *gl)
 {
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
-	if (likely(!gfs2_withdrawn(sdp)))
+	if (!gfs2_withdrawing_or_withdrawn(sdp))
 		return false;
 	if (gl->gl_ops->go_flags & GLOF_NONDISK)
 		return false;
@@ -278,7 +278,7 @@ static void __gfs2_glock_put(struct gfs2_glock *gl)
 	GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
 	if (mapping) {
 		truncate_inode_pages_final(mapping);
-		if (!gfs2_withdrawn(sdp))
+		if (!gfs2_withdrawing_or_withdrawn(sdp))
 			GLOCK_BUG_ON(gl, !mapping_empty(mapping));
 	}
 	trace_gfs2_glock_put(gl);
@@ -516,6 +516,23 @@ static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
 	return NULL;
 }
 
+/**
+ * find_last_waiter - find the last gh that's waiting for the glock
+ * @gl: the glock
+ *
+ * This also is a fast way of finding out if there are any waiters.
+ */
+
+static inline struct gfs2_holder *find_last_waiter(const struct gfs2_glock *gl)
+{
+	struct gfs2_holder *gh;
+
+	if (list_empty(&gl->gl_holders))
+		return NULL;
+	gh = list_last_entry(&gl->gl_holders, struct gfs2_holder, gh_list);
+	return test_bit(HIF_HOLDER, &gh->gh_iflags) ? NULL : gh;
+}
+
 /**
  * state_change - record that the glock is now in a different state
  * @gl: the glock
@@ -757,7 +774,7 @@ __acquires(&gl->gl_lockref.lock)
 	 * gfs2_gl_hash_clear calls clear_glock) and recovery is complete
 	 * then it's okay to tell dlm to unlock it.
 	 */
-	if (unlikely(sdp->sd_log_error && !gfs2_withdrawn(sdp)))
+	if (unlikely(sdp->sd_log_error) && !gfs2_withdrawing_or_withdrawn(sdp))
 		gfs2_withdraw_delayed(sdp);
 	if (glock_blocked_by_withdraw(gl) &&
 	    (target != LM_ST_UNLOCKED ||
@@ -794,7 +811,7 @@ __acquires(&gl->gl_lockref.lock)
 			gfs2_glock_queue_work(gl, 0);
 		} else if (ret) {
 			fs_err(sdp, "lm_lock ret %d\n", ret);
-			GLOCK_BUG_ON(gl, !gfs2_withdrawn(sdp));
+			GLOCK_BUG_ON(gl, !gfs2_withdrawing_or_withdrawn(sdp));
 		}
 	} else { /* lock_nolock */
 		finish_xmote(gl, target);
@@ -1555,11 +1572,30 @@ __acquires(&gl->gl_lockref.lock)
 int gfs2_glock_nq(struct gfs2_holder *gh)
 {
 	struct gfs2_glock *gl = gh->gh_gl;
-	int error = 0;
+	int error;
 
 	if (glock_blocked_by_withdraw(gl) && !(gh->gh_flags & LM_FLAG_NOEXP))
 		return -EIO;
 
+	if (gh->gh_flags & GL_NOBLOCK) {
+		struct gfs2_holder *current_gh;
+
+		error = -ECHILD;
+		spin_lock(&gl->gl_lockref.lock);
+		if (find_last_waiter(gl))
+			goto unlock;
+		current_gh = find_first_holder(gl);
+		if (!may_grant(gl, current_gh, gh))
+			goto unlock;
+		set_bit(HIF_HOLDER, &gh->gh_iflags);
+		list_add_tail(&gh->gh_list, &gl->gl_holders);
+		trace_gfs2_promote(gh);
+		error = 0;
+unlock:
+		spin_unlock(&gl->gl_lockref.lock);
+		return error;
+	}
+
 	if (test_bit(GLF_LRU, &gl->gl_flags))
 		gfs2_glock_remove_from_lru(gl);
 
@@ -1575,6 +1611,7 @@ int gfs2_glock_nq(struct gfs2_holder *gh)
 	run_queue(gl, 1);
 	spin_unlock(&gl->gl_lockref.lock);
 
+	error = 0;
 	if (!(gh->gh_flags & GL_ASYNC))
 		error = gfs2_glock_wait(gh);
 

fs/gfs2/glock.h

@@ -84,6 +84,7 @@ enum {
 #define GL_SKIP			0x0100
 #define GL_NOPID		0x0200
 #define GL_NOCACHE		0x0400
+#define GL_NOBLOCK		0x0800
 
 /*
  * lm_async_cb return flags

fs/gfs2/glops.c

@@ -174,7 +174,7 @@ static int gfs2_rgrp_metasync(struct gfs2_glock *gl)
 
 	filemap_fdatawrite_range(metamapping, start, end);
 	error = filemap_fdatawait_range(metamapping, start, end);
-	WARN_ON_ONCE(error && !gfs2_withdrawn(sdp));
+	WARN_ON_ONCE(error && !gfs2_withdrawing_or_withdrawn(sdp));
 	mapping_set_error(metamapping, error);
 	if (error)
 		gfs2_io_error(sdp);
@@ -494,7 +494,7 @@ int gfs2_inode_refresh(struct gfs2_inode *ip)
 
 /**
  * inode_go_instantiate - read in an inode if necessary
- * @gh: The glock holder
+ * @gl: The glock
  *
  * Returns: errno
  */

fs/gfs2/inode.c

@@ -1882,10 +1882,10 @@ int gfs2_permission(struct mnt_idmap *idmap, struct inode *inode,
 		WARN_ON_ONCE(!may_not_block);
 		return -ECHILD;
         }
-	if (gfs2_glock_is_locked_by_me(gl) == NULL) {
-		if (may_not_block)
-			return -ECHILD;
-		error = gfs2_glock_nq_init(gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
+	if (gfs2_glock_is_locked_by_me(ip->i_gl) == NULL) {
+		int noblock = may_not_block ? GL_NOBLOCK : 0;
+		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
+					   LM_FLAG_ANY | noblock, &i_gh);
 		if (error)
 			return error;
 	}

fs/gfs2/lock_dlm.c

@@ -1122,7 +1122,7 @@ static void gdlm_recover_prep(void *arg)
 	struct gfs2_sbd *sdp = arg;
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 
-	if (gfs2_withdrawn(sdp)) {
+	if (gfs2_withdrawing_or_withdrawn(sdp)) {
 		fs_err(sdp, "recover_prep ignored due to withdraw.\n");
 		return;
 	}
@@ -1148,7 +1148,7 @@ static void gdlm_recover_slot(void *arg, struct dlm_slot *slot)
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 	int jid = slot->slot - 1;
 
-	if (gfs2_withdrawn(sdp)) {
+	if (gfs2_withdrawing_or_withdrawn(sdp)) {
 		fs_err(sdp, "recover_slot jid %d ignored due to withdraw.\n",
 		       jid);
 		return;
@@ -1177,7 +1177,7 @@ static void gdlm_recover_done(void *arg, struct dlm_slot *slots, int num_slots,
 	struct gfs2_sbd *sdp = arg;
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 
-	if (gfs2_withdrawn(sdp)) {
+	if (gfs2_withdrawing_or_withdrawn(sdp)) {
 		fs_err(sdp, "recover_done ignored due to withdraw.\n");
 		return;
 	}
@@ -1208,7 +1208,7 @@ static void gdlm_recovery_result(struct gfs2_sbd *sdp, unsigned int jid,
 {
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 
-	if (gfs2_withdrawn(sdp)) {
+	if (gfs2_withdrawing_or_withdrawn(sdp)) {
 		fs_err(sdp, "recovery_result jid %d ignored due to withdraw.\n",
 		       jid);
 		return;