[PATCH 6.12 0734/1276] afs: Fix afs_atcell_get_link() to handle RCU pathwalk

[PATCH 6.12 0734/1276] afs: Fix afs_atcell_get_link() to handle RCU pathwalk

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 823869e1e61607ab0d433de3c8abed221dc80a5e ]

The ->get_link() method may be entered under RCU pathwalk conditions (in
which case, the dentry pointer is NULL).  This is not taken account of by
afs_atcell_get_link() and lockdep will complain when it tries to lock an
rwsem.

Fix this by marking net->ws_cell as __rcu and using RCU access macros on it
and by making afs_atcell_get_link() just return a pointer to the name in
RCU pathwalk without taking net->cells_lock or a ref on the cell as RCU
will protect the name storage (the cell is already freed via call_rcu()).

Fixes: 30bca65bbbae ("afs: Make /afs/@cell and /afs/.@cell symlinks")
Reported-by: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20250310094206.801057-2-dhowells@redhat.com/ # v4
Stable-dep-of: c9c3b615a462 ("afs: Fix misplaced inc of net->cells_outstanding")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/afs/cell.c     | 11 ++++++-----
 fs/afs/dynroot.c  | 15 +++++++++++++--
 fs/afs/internal.h |  2 +-
 fs/afs/proc.c     |  4 ++--
 4 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index cee42646736c86..96a6781f365303 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -64,7 +64,8 @@ static struct afs_cell *afs_find_cell_locked(struct afs_net *net,
 		return ERR_PTR(-ENAMETOOLONG);
 
 	if (!name) {
-		cell = net->ws_cell;
+		cell = rcu_dereference_protected(net->ws_cell,
+						 lockdep_is_held(&net->cells_lock));
 		if (!cell)
 			return ERR_PTR(-EDESTADDRREQ);
 		goto found;
@@ -388,8 +389,8 @@ int afs_cell_init(struct afs_net *net, const char *rootcell)
 	/* install the new cell */
 	down_write(&net->cells_lock);
 	afs_see_cell(new_root, afs_cell_trace_see_ws);
-	old_root = net->ws_cell;
-	net->ws_cell = new_root;
+	old_root = rcu_replace_pointer(net->ws_cell, new_root,
+				       lockdep_is_held(&net->cells_lock));
 	up_write(&net->cells_lock);
 
 	afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);
@@ -945,8 +946,8 @@ void afs_cell_purge(struct afs_net *net)
 	_enter("");
 
 	down_write(&net->cells_lock);
-	ws = net->ws_cell;
-	net->ws_cell = NULL;
+	ws = rcu_replace_pointer(net->ws_cell, NULL,
+				 lockdep_is_held(&net->cells_lock));
 	up_write(&net->cells_lock);
 	afs_unuse_cell(net, ws, afs_cell_trace_unuse_ws);
 
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index d8bf52f77d9302..008698d706caa4 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -314,12 +314,23 @@ static const char *afs_atcell_get_link(struct dentry *dentry, struct inode *inod
 	const char *name;
 	bool dotted = vnode->fid.vnode == 3;
 
-	if (!net->ws_cell)
+	if (!dentry) {
+		/* We're in RCU-pathwalk. */
+		cell = rcu_dereference(net->ws_cell);
+		if (dotted)
+			name = cell->name - 1;
+		else
+			name = cell->name;
+		/* Shouldn't need to set a delayed call. */
+		return name;
+	}
+
+	if (!rcu_access_pointer(net->ws_cell))
 		return ERR_PTR(-ENOENT);
 
 	down_read(&net->cells_lock);
 
-	cell = net->ws_cell;
+	cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));
 	if (dotted)
 		name = cell->name - 1;
 	else
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index d9760b2a8d8de4..18f410559fe87b 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -302,7 +302,7 @@ struct afs_net {
 
 	/* Cell database */
 	struct rb_root		cells;
-	struct afs_cell		*ws_cell;
+	struct afs_cell __rcu	*ws_cell;
 	struct work_struct	cells_manager;
 	struct timer_list	cells_timer;
 	atomic_t		cells_outstanding;
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index e7614f4f30c21e..12c88d8be3fe8b 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -206,7 +206,7 @@ static int afs_proc_rootcell_show(struct seq_file *m, void *v)
 
 	net = afs_seq2net_single(m);
 	down_read(&net->cells_lock);
-	cell = net->ws_cell;
+	cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));
 	if (cell)
 		seq_printf(m, "%s\n", cell->name);
 	up_read(&net->cells_lock);
@@ -242,7 +242,7 @@ static int afs_proc_rootcell_write(struct file *file, char *buf, size_t size)
 
 	ret = -EEXIST;
 	inode_lock(file_inode(file));
-	if (!net->ws_cell)
+	if (!rcu_access_pointer(net->ws_cell))
 		ret = afs_cell_init(net, buf);
 	else
 		printk("busy\n");
-- 
2.53.0

[PATCH 6.12 0735/1276] afs: Remove the "autocell" mount option

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 4c5ad63f85ef984cc809538b2dcbc113aed82330 ]

Remove the "autocell" mount option.  It was an attempt to do automounting
of arbitrary cells based on what the user looked up but within the root
directory of a mounted volume.  This isn't really the right thing to do,
and using the "dyn" mount option to get the dynamic root is the right way
to do it.  The kafs-client package uses "-o dyn" when mounting /afs, so it
should be safe to drop "-o autocell".

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20250224234154.2014840-7-dhowells@redhat.com/ # v1
Link: https://lore.kernel.org/r/20250310094206.801057-3-dhowells@redhat.com/ # v4
Stable-dep-of: c9c3b615a462 ("afs: Fix misplaced inc of net->cells_outstanding")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/afs/dir.c      | 5 ++---
 fs/afs/dynroot.c  | 5 +----
 fs/afs/internal.h | 2 --
 fs/afs/super.c    | 5 -----
 4 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 50edd1cae28ace..037c89e05f4cf0 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1031,9 +1031,8 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 	inode = afs_do_lookup(dir, dentry, key);
 	key_put(key);
 	if (inode == ERR_PTR(-ENOENT))
-		inode = afs_try_auto_mntpt(dentry, dir);
-
-	if (!IS_ERR_OR_NULL(inode))
+		inode = NULL;
+	else if (!IS_ERR_OR_NULL(inode))
 		fid = AFS_FS_I(inode)->fid;
 
 	_debug("splice %p", dentry->d_inode);
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index 008698d706caa4..0b4cc291c65e2d 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -155,7 +155,7 @@ static int afs_probe_cell_name(struct dentry *dentry)
  * Try to auto mount the mountpoint with pseudo directory, if the autocell
  * operation is setted.
  */
-struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
+static struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
 {
 	struct afs_vnode *vnode = AFS_FS_I(dir);
 	struct inode *inode;
@@ -164,9 +164,6 @@ struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
 	_enter("%p{%pd}, {%llx:%llu}",
 	       dentry, dentry, vnode->fid.vid, vnode->fid.vnode);
 
-	if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
-		goto out;
-
 	ret = afs_probe_cell_name(dentry);
 	if (ret < 0)
 		goto out;
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 18f410559fe87b..aa66d8010f8942 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -714,7 +714,6 @@ struct afs_vnode {
 #define AFS_VNODE_ZAP_DATA	3		/* set if vnode's data should be invalidated */
 #define AFS_VNODE_DELETED	4		/* set if vnode deleted on server */
 #define AFS_VNODE_MOUNTPOINT	5		/* set if vnode is a mountpoint symlink */
-#define AFS_VNODE_AUTOCELL	6		/* set if Vnode is an auto mount point */
 #define AFS_VNODE_PSEUDODIR	7 		/* set if Vnode is a pseudo directory */
 #define AFS_VNODE_NEW_CONTENT	8		/* Set if file has new content (create/trunc-0) */
 #define AFS_VNODE_SILLY_DELETED	9		/* Set if file has been silly-deleted */
@@ -1089,7 +1088,6 @@ extern int afs_silly_iput(struct dentry *, struct inode *);
 extern const struct inode_operations afs_dynroot_inode_operations;
 extern const struct dentry_operations afs_dynroot_dentry_operations;
 
-extern struct inode *afs_try_auto_mntpt(struct dentry *, struct inode *);
 extern int afs_dynroot_mkdir(struct afs_net *, struct afs_cell *);
 extern void afs_dynroot_rmdir(struct afs_net *, struct afs_cell *);
 extern int afs_dynroot_populate(struct super_block *);
diff --git a/fs/afs/super.c b/fs/afs/super.c
index f3ba1c3e72f5b8..259c48e37537eb 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -194,8 +194,6 @@ static int afs_show_options(struct seq_file *m, struct dentry *root)
 
 	if (as->dyn_root)
 		seq_puts(m, ",dyn");
-	if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
-		seq_puts(m, ",autocell");
 	switch (as->flock_mode) {
 	case afs_flock_mode_unset:	break;
 	case afs_flock_mode_local:	p = "local";	break;
@@ -478,9 +476,6 @@ static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
-	if (ctx->autocell || as->dyn_root)
-		set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
-
 	ret = -ENOMEM;
 	sb->s_root = d_make_root(inode);
 	if (!sb->s_root)
-- 
2.53.0

[PATCH 6.12 0736/1276] afs: Change dynroot to create contents on demand

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 1d0b929fc070b4115403a0a6206a0c6a62dd61f5 ]

Change the AFS dynamic root to do things differently:

 (1) Rather than having the creation of cell records create inodes and
     dentries for cell mountpoints, create them on demand during lookup.

     This simplifies cell management and locking as we no longer have to
     create these objects in advance *and* on speculative lookup by the
     user for a cell that isn't precreated.

 (2) Rather than using the libfs dentry-based readdir (the dentries now no
     longer exist until accessed from (1)), have readdir generate the
     contents by reading the list of cells.  The @cell symlinks get pushed
     in positions 2 and 3 if rootcell has been configured.

 (3) Make the @cell symlink dentries persist for the life of the superblock
     or until reclaimed, but make cell mountpoints disappear immediately if
     unused.

     It's not perfect as someone doing an "ls -l /afs" may create a whole
     bunch of dentries which will be garbage collected immediately.  But
     any dentry that gets automounted will be pinned by the mount, so it
     shouldn't be too bad.

 (4) Allocate the inode numbers for the cell mountpoints from an IDR to
     prevent duplicates appearing in the event it cycles round.  The number
     allocated from the IDR is doubled to provide two inode numbers - one
     for the normal cell name (RO) and one for the dotted cell name (RW).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20250224234154.2014840-8-dhowells@redhat.com/ # v1
Link: https://lore.kernel.org/r/20250310094206.801057-4-dhowells@redhat.com/ # v4
Stable-dep-of: c9c3b615a462 ("afs: Fix misplaced inc of net->cells_outstanding")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/afs/cell.c              |   9 +-
 fs/afs/dynroot.c           | 482 +++++++++++++++----------------------
 fs/afs/internal.h          |   8 +-
 fs/afs/main.c              |   3 +
 fs/afs/super.c             |   8 +-
 include/trace/events/afs.h |   2 +
 6 files changed, 213 insertions(+), 299 deletions(-)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index 96a6781f365303..c2e44cd2eb96cb 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -204,7 +204,13 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
 	cell->dns_status = vllist->status;
 	smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */
 	atomic_inc(&net->cells_outstanding);
+	ret = idr_alloc_cyclic(&net->cells_dyn_ino, cell,
+			       2, INT_MAX / 2, GFP_KERNEL);
+	if (ret < 0)
+		goto error;
+	cell->dynroot_ino = ret;
 	cell->debug_id = atomic_inc_return(&cell_debug_id);
+
 	trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);
 
 	_leave(" = %p", cell);
@@ -513,6 +519,7 @@ static void afs_cell_destroy(struct rcu_head *rcu)
 	afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
 	afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);
 	key_put(cell->anonymous_key);
+	idr_remove(&net->cells_dyn_ino, cell->dynroot_ino);
 	kfree(cell->name - 1);
 	kfree(cell);
 
@@ -706,7 +713,6 @@ static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
 	if (cell->proc_link.next)
 		cell->proc_link.next->pprev = &cell->proc_link.next;
 
-	afs_dynroot_mkdir(net, cell);
 	mutex_unlock(&net->proc_cells_lock);
 	return 0;
 }
@@ -723,7 +729,6 @@ static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
 	mutex_lock(&net->proc_cells_lock);
 	if (!hlist_unhashed(&cell->proc_link))
 		hlist_del_rcu(&cell->proc_link);
-	afs_dynroot_rmdir(net, cell);
 	mutex_unlock(&net->proc_cells_lock);
 
 	_leave("");
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index 0b4cc291c65e2d..eb20e231d7ac20 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -10,16 +10,19 @@
 #include <linux/dns_resolver.h>
 #include "internal.h"
 
-static atomic_t afs_autocell_ino;
+#define AFS_MIN_DYNROOT_CELL_INO 4 /* Allow for ., .., @cell, .@cell */
+#define AFS_MAX_DYNROOT_CELL_INO ((unsigned int)INT_MAX)
+
+static struct dentry *afs_lookup_atcell(struct inode *dir, struct dentry *dentry, ino_t ino);
 
 /*
  * iget5() comparator for inode created by autocell operations
- *
- * These pseudo inodes don't match anything.
  */
 static int afs_iget5_pseudo_test(struct inode *inode, void *opaque)
 {
-	return 0;
+	struct afs_fid *fid = opaque;
+
+	return inode->i_ino == fid->vnode;
 }
 
 /*
@@ -39,28 +42,16 @@ static int afs_iget5_pseudo_set(struct inode *inode, void *opaque)
 }
 
 /*
- * Create an inode for a dynamic root directory or an autocell dynamic
- * automount dir.
+ * Create an inode for an autocell dynamic automount dir.
  */
-struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
+static struct inode *afs_iget_pseudo_dir(struct super_block *sb, ino_t ino)
 {
-	struct afs_super_info *as = AFS_FS_S(sb);
 	struct afs_vnode *vnode;
 	struct inode *inode;
-	struct afs_fid fid = {};
+	struct afs_fid fid = { .vnode = ino, .unique = 1, };
 
 	_enter("");
 
-	if (as->volume)
-		fid.vid = as->volume->vid;
-	if (root) {
-		fid.vnode = 1;
-		fid.unique = 1;
-	} else {
-		fid.vnode = atomic_inc_return(&afs_autocell_ino);
-		fid.unique = 0;
-	}
-
 	inode = iget5_locked(sb, fid.vnode,
 			     afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
 	if (!inode) {
@@ -73,112 +64,70 @@ struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root)
 
 	vnode = AFS_FS_I(inode);
 
-	/* there shouldn't be an existing inode */
-	BUG_ON(!(inode->i_state & I_NEW));
-
-	netfs_inode_init(&vnode->netfs, NULL, false);
-	inode->i_size		= 0;
-	inode->i_mode		= S_IFDIR | S_IRUGO | S_IXUGO;
-	if (root) {
-		inode->i_op	= &afs_dynroot_inode_operations;
-		inode->i_fop	= &simple_dir_operations;
-	} else {
-		inode->i_op	= &afs_autocell_inode_operations;
-	}
-	set_nlink(inode, 2);
-	inode->i_uid		= GLOBAL_ROOT_UID;
-	inode->i_gid		= GLOBAL_ROOT_GID;
-	simple_inode_init_ts(inode);
-	inode->i_blocks		= 0;
-	inode->i_generation	= 0;
-
-	set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
-	if (!root) {
+	if (inode->i_state & I_NEW) {
+		netfs_inode_init(&vnode->netfs, NULL, false);
+		simple_inode_init_ts(inode);
+		set_nlink(inode, 2);
+		inode->i_size		= 0;
+		inode->i_mode		= S_IFDIR | 0555;
+		inode->i_op		= &afs_autocell_inode_operations;
+		inode->i_uid		= GLOBAL_ROOT_UID;
+		inode->i_gid		= GLOBAL_ROOT_GID;
+		inode->i_blocks		= 0;
+		inode->i_generation	= 0;
+		inode->i_flags		|= S_AUTOMOUNT | S_NOATIME;
+
+		set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
 		set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
-		inode->i_flags |= S_AUTOMOUNT;
-	}
 
-	inode->i_flags |= S_NOATIME;
-	unlock_new_inode(inode);
+		unlock_new_inode(inode);
+	}
 	_leave(" = %p", inode);
 	return inode;
 }
 
 /*
- * Probe to see if a cell may exist.  This prevents positive dentries from
- * being created unnecessarily.
+ * Try to automount the mountpoint with pseudo directory, if the autocell
+ * option is set.
  */
-static int afs_probe_cell_name(struct dentry *dentry)
+static struct dentry *afs_dynroot_lookup_cell(struct inode *dir, struct dentry *dentry,
+					      unsigned int flags)
 {
-	struct afs_cell *cell;
+	struct afs_cell *cell = NULL;
 	struct afs_net *net = afs_d2net(dentry);
+	struct inode *inode = NULL;
 	const char *name = dentry->d_name.name;
 	size_t len = dentry->d_name.len;
-	char *result = NULL;
-	int ret;
+	bool dotted = false;
+	int ret = -ENOENT;
 
 	/* Names prefixed with a dot are R/W mounts. */
 	if (name[0] == '.') {
-		if (len == 1)
-			return -EINVAL;
 		name++;
 		len--;
+		dotted = true;
 	}
 
-	cell = afs_find_cell(net, name, len, afs_cell_trace_use_probe);
-	if (!IS_ERR(cell)) {
-		afs_unuse_cell(net, cell, afs_cell_trace_unuse_probe);
-		return 0;
-	}
-
-	ret = dns_query(net->net, "afsdb", name, len, "srv=1",
-			&result, NULL, false);
-	if (ret == -ENODATA || ret == -ENOKEY || ret == 0)
-		ret = -ENOENT;
-	if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) {
-		struct dns_server_list_v1_header *v1 = (void *)result;
-
-		if (v1->hdr.zero == 0 &&
-		    v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST &&
-		    v1->hdr.version == 1 &&
-		    (v1->status != DNS_LOOKUP_GOOD &&
-		     v1->status != DNS_LOOKUP_GOOD_WITH_BAD))
-			return -ENOENT;
-
+	cell = afs_lookup_cell(net, name, len, NULL, false);
+	if (IS_ERR(cell)) {
+		ret = PTR_ERR(cell);
+		goto out_no_cell;
 	}
 
-	kfree(result);
-	return ret;
-}
-
-/*
- * Try to auto mount the mountpoint with pseudo directory, if the autocell
- * operation is setted.
- */
-static struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
-{
-	struct afs_vnode *vnode = AFS_FS_I(dir);
-	struct inode *inode;
-	int ret = -ENOENT;
-
-	_enter("%p{%pd}, {%llx:%llu}",
-	       dentry, dentry, vnode->fid.vid, vnode->fid.vnode);
-
-	ret = afs_probe_cell_name(dentry);
-	if (ret < 0)
-		goto out;
-
-	inode = afs_iget_pseudo_dir(dir->i_sb, false);
+	inode = afs_iget_pseudo_dir(dir->i_sb, cell->dynroot_ino * 2 + dotted);
 	if (IS_ERR(inode)) {
 		ret = PTR_ERR(inode);
 		goto out;
 	}
 
-	_leave("= %p", inode);
-	return inode;
+	dentry->d_fsdata = cell;
+	return d_splice_alias(inode, dentry);
 
 out:
-	_leave("= %d", ret);
+	afs_unuse_cell(cell->net, cell, afs_cell_trace_unuse_lookup_dynroot);
+out_no_cell:
+	if (!inode)
+		return d_splice_alias(inode, dentry);
 	return ret == -ENOENT ? NULL : ERR_PTR(ret);
 }
 
@@ -190,8 +139,6 @@ static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentr
 {
 	_enter("%pd", dentry);
 
-	ASSERTCMP(d_inode(dentry), ==, NULL);
-
 	if (flags & LOOKUP_CREATE)
 		return ERR_PTR(-EOPNOTSUPP);
 
@@ -200,98 +147,49 @@ static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentr
 		return ERR_PTR(-ENAMETOOLONG);
 	}
 
-	return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
+	if (dentry->d_name.len == 5 &&
+	    memcmp(dentry->d_name.name, "@cell", 5) == 0)
+		return afs_lookup_atcell(dir, dentry, 2);
+
+	if (dentry->d_name.len == 6 &&
+	    memcmp(dentry->d_name.name, ".@cell", 6) == 0)
+		return afs_lookup_atcell(dir, dentry, 3);
+
+	return afs_dynroot_lookup_cell(dir, dentry, flags);
 }
 
 const struct inode_operations afs_dynroot_inode_operations = {
 	.lookup		= afs_dynroot_lookup,
 };
 
-const struct dentry_operations afs_dynroot_dentry_operations = {
-	.d_delete	= always_delete_dentry,
-	.d_release	= afs_d_release,
-	.d_automount	= afs_d_automount,
-};
-
-/*
- * Create a manually added cell mount directory.
- * - The caller must hold net->proc_cells_lock
- */
-int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
-{
-	struct super_block *sb = net->dynroot_sb;
-	struct dentry *root, *subdir, *dsubdir;
-	char *dotname = cell->name - 1;
-	int ret;
-
-	if (!sb || atomic_read(&sb->s_active) == 0)
-		return 0;
-
-	/* Let the ->lookup op do the creation */
-	root = sb->s_root;
-	inode_lock(root->d_inode);
-	subdir = lookup_one_len(cell->name, root, cell->name_len);
-	if (IS_ERR(subdir)) {
-		ret = PTR_ERR(subdir);
-		goto unlock;
-	}
-
-	dsubdir = lookup_one_len(dotname, root, cell->name_len + 1);
-	if (IS_ERR(dsubdir)) {
-		ret = PTR_ERR(dsubdir);
-		dput(subdir);
-		goto unlock;
-	}
-
-	/* Note that we're retaining extra refs on the dentries. */
-	subdir->d_fsdata = (void *)1UL;
-	dsubdir->d_fsdata = (void *)1UL;
-	ret = 0;
-unlock:
-	inode_unlock(root->d_inode);
-	return ret;
-}
-
-static void afs_dynroot_rm_one_dir(struct dentry *root, const char *name, size_t name_len)
+static void afs_dynroot_d_release(struct dentry *dentry)
 {
-	struct dentry *subdir;
-
-	/* Don't want to trigger a lookup call, which will re-add the cell */
-	subdir = try_lookup_one_len(name, root, name_len);
-	if (IS_ERR_OR_NULL(subdir)) {
-		_debug("lookup %ld", PTR_ERR(subdir));
-		return;
-	}
-
-	_debug("rmdir %pd %u", subdir, d_count(subdir));
+	struct afs_cell *cell = dentry->d_fsdata;
 
-	if (subdir->d_fsdata) {
-		_debug("unpin %u", d_count(subdir));
-		subdir->d_fsdata = NULL;
-		dput(subdir);
-	}
-	dput(subdir);
+	afs_unuse_cell(cell->net, cell, afs_cell_trace_unuse_dynroot_mntpt);
 }
 
 /*
- * Remove a manually added cell mount directory.
- * - The caller must hold net->proc_cells_lock
+ * Keep @cell symlink dentries around, but only keep cell autodirs when they're
+ * being used.
  */
-void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
+static int afs_dynroot_delete_dentry(const struct dentry *dentry)
 {
-	struct super_block *sb = net->dynroot_sb;
-	char *dotname = cell->name - 1;
-
-	if (!sb || atomic_read(&sb->s_active) == 0)
-		return;
+	const struct qstr *name = &dentry->d_name;
 
-	inode_lock(sb->s_root->d_inode);
-	afs_dynroot_rm_one_dir(sb->s_root, cell->name, cell->name_len);
-	afs_dynroot_rm_one_dir(sb->s_root, dotname, cell->name_len + 1);
-	inode_unlock(sb->s_root->d_inode);
-	_leave("");
+	if (name->len == 5 && memcmp(name->name, "@cell", 5) == 0)
+		return 0;
+	if (name->len == 6 && memcmp(name->name, ".@cell", 6) == 0)
+		return 0;
+	return 1;
 }
 
+const struct dentry_operations afs_dynroot_dentry_operations = {
+	.d_delete	= afs_dynroot_delete_dentry,
+	.d_release	= afs_dynroot_d_release,
+	.d_automount	= afs_d_automount,
+};
+
 static void afs_atcell_delayed_put_cell(void *arg)
 {
 	struct afs_cell *cell = arg;
@@ -344,149 +242,163 @@ static const struct inode_operations afs_atcell_inode_operations = {
 };
 
 /*
- * Look up @cell or .@cell in a dynroot directory.  This is a substitution for
- * the local cell name for the net namespace.
+ * Create an inode for the @cell or .@cell symlinks.
  */
-static struct dentry *afs_dynroot_create_symlink(struct dentry *root, const char *name)
+static struct dentry *afs_lookup_atcell(struct inode *dir, struct dentry *dentry, ino_t ino)
 {
 	struct afs_vnode *vnode;
-	struct afs_fid fid = { .vnode = 2, .unique = 1, };
-	struct dentry *dentry;
 	struct inode *inode;
+	struct afs_fid fid = { .vnode = ino, .unique = 1, };
 
-	if (name[0] == '.')
-		fid.vnode = 3;
-
-	dentry = d_alloc_name(root, name);
-	if (!dentry)
-		return ERR_PTR(-ENOMEM);
-
-	inode = iget5_locked(dentry->d_sb, fid.vnode,
+	inode = iget5_locked(dir->i_sb, fid.vnode,
 			     afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
-	if (!inode) {
-		dput(dentry);
+	if (!inode)
 		return ERR_PTR(-ENOMEM);
-	}
 
 	vnode = AFS_FS_I(inode);
 
-	/* there shouldn't be an existing inode */
-	if (WARN_ON_ONCE(!(inode->i_state & I_NEW))) {
-		iput(inode);
-		dput(dentry);
-		return ERR_PTR(-EIO);
+	if (inode->i_state & I_NEW) {
+		netfs_inode_init(&vnode->netfs, NULL, false);
+		simple_inode_init_ts(inode);
+		set_nlink(inode, 1);
+		inode->i_size		= 0;
+		inode->i_mode		= S_IFLNK | 0555;
+		inode->i_op		= &afs_atcell_inode_operations;
+		inode->i_uid		= GLOBAL_ROOT_UID;
+		inode->i_gid		= GLOBAL_ROOT_GID;
+		inode->i_blocks		= 0;
+		inode->i_generation	= 0;
+		inode->i_flags		|= S_NOATIME;
+
+		unlock_new_inode(inode);
 	}
-
-	netfs_inode_init(&vnode->netfs, NULL, false);
-	simple_inode_init_ts(inode);
-	set_nlink(inode, 1);
-	inode->i_size		= 0;
-	inode->i_mode		= S_IFLNK | 0555;
-	inode->i_op		= &afs_atcell_inode_operations;
-	inode->i_uid		= GLOBAL_ROOT_UID;
-	inode->i_gid		= GLOBAL_ROOT_GID;
-	inode->i_blocks		= 0;
-	inode->i_generation	= 0;
-	inode->i_flags		|= S_NOATIME;
-
-	unlock_new_inode(inode);
-	d_splice_alias(inode, dentry);
-	return dentry;
+	return d_splice_alias(inode, dentry);
 }
 
 /*
- * Create @cell and .@cell symlinks.
+ * Transcribe the cell database into readdir content under the RCU read lock.
+ * Each cell produces two entries, one prefixed with a dot and one not.
  */
-static int afs_dynroot_symlink(struct afs_net *net)
+static int afs_dynroot_readdir_cells(struct afs_net *net, struct dir_context *ctx)
 {
-	struct super_block *sb = net->dynroot_sb;
-	struct dentry *root, *symlink, *dsymlink;
-	int ret;
-
-	/* Let the ->lookup op do the creation */
-	root = sb->s_root;
-	inode_lock(root->d_inode);
-	symlink = afs_dynroot_create_symlink(root, "@cell");
-	if (IS_ERR(symlink)) {
-		ret = PTR_ERR(symlink);
-		goto unlock;
-	}
+	const struct afs_cell *cell;
+	loff_t newpos;
+
+	_enter("%llu", ctx->pos);
+
+	for (;;) {
+		unsigned int ix = ctx->pos >> 1;
+
+		cell = idr_get_next(&net->cells_dyn_ino, &ix);
+		if (!cell)
+			return 0;
+		if (READ_ONCE(cell->state) == AFS_CELL_FAILED ||
+		    READ_ONCE(cell->state) == AFS_CELL_REMOVED) {
+			ctx->pos += 2;
+			ctx->pos &= ~1;
+			continue;
+		}
 
-	dsymlink = afs_dynroot_create_symlink(root, ".@cell");
-	if (IS_ERR(dsymlink)) {
-		ret = PTR_ERR(dsymlink);
-		dput(symlink);
-		goto unlock;
-	}
+		newpos = ix << 1;
+		if (newpos > ctx->pos)
+			ctx->pos = newpos;
 
-	/* Note that we're retaining extra refs on the dentries. */
-	symlink->d_fsdata = (void *)1UL;
-	dsymlink->d_fsdata = (void *)1UL;
-	ret = 0;
-unlock:
-	inode_unlock(root->d_inode);
-	return ret;
+		_debug("pos %llu -> cell %u", ctx->pos, cell->dynroot_ino);
+
+		if ((ctx->pos & 1) == 0) {
+			if (!dir_emit(ctx, cell->name, cell->name_len,
+				      cell->dynroot_ino, DT_DIR))
+				return 0;
+			ctx->pos++;
+		}
+		if ((ctx->pos & 1) == 1) {
+			if (!dir_emit(ctx, cell->name - 1, cell->name_len + 1,
+				      cell->dynroot_ino + 1, DT_DIR))
+				return 0;
+			ctx->pos++;
+		}
+	}
+	return 0;
 }
 
 /*
- * Populate a newly created dynamic root with cell names.
+ * Read the AFS dynamic root directory.  This produces a list of cellnames,
+ * dotted and undotted, along with @cell and .@cell links if configured.
  */
-int afs_dynroot_populate(struct super_block *sb)
+static int afs_dynroot_readdir(struct file *file, struct dir_context *ctx)
 {
-	struct afs_cell *cell;
-	struct afs_net *net = afs_sb2net(sb);
-	int ret;
+	struct afs_net *net = afs_d2net(file->f_path.dentry);
+	int ret = 0;
 
-	mutex_lock(&net->proc_cells_lock);
-
-	net->dynroot_sb = sb;
-	ret = afs_dynroot_symlink(net);
-	if (ret < 0)
-		goto error;
+	if (!dir_emit_dots(file, ctx))
+		return 0;
 
-	hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
-		ret = afs_dynroot_mkdir(net, cell);
-		if (ret < 0)
-			goto error;
+	if (ctx->pos == 2) {
+		if (rcu_access_pointer(net->ws_cell) &&
+		    !dir_emit(ctx, "@cell", 5, 2, DT_LNK))
+			return 0;
+		ctx->pos = 3;
+	}
+	if (ctx->pos == 3) {
+		if (rcu_access_pointer(net->ws_cell) &&
+		    !dir_emit(ctx, ".@cell", 6, 3, DT_LNK))
+			return 0;
+		ctx->pos = 4;
 	}
 
-	ret = 0;
-out:
-	mutex_unlock(&net->proc_cells_lock);
+	if ((unsigned long long)ctx->pos <= AFS_MAX_DYNROOT_CELL_INO) {
+		rcu_read_lock();
+		ret = afs_dynroot_readdir_cells(net, ctx);
+		rcu_read_unlock();
+	}
 	return ret;
-
-error:
-	net->dynroot_sb = NULL;
-	goto out;
 }
 
+static const struct file_operations afs_dynroot_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= afs_dynroot_readdir,
+	.fsync		= noop_fsync,
+};
+
 /*
- * When a dynamic root that's in the process of being destroyed, depopulate it
- * of pinned directories.
+ * Create an inode for a dynamic root directory.
  */
-void afs_dynroot_depopulate(struct super_block *sb)
+struct inode *afs_dynroot_iget_root(struct super_block *sb)
 {
-	struct afs_net *net = afs_sb2net(sb);
-	struct dentry *root = sb->s_root, *subdir;
-
-	/* Prevent more subdirs from being created */
-	mutex_lock(&net->proc_cells_lock);
-	if (net->dynroot_sb == sb)
-		net->dynroot_sb = NULL;
-	mutex_unlock(&net->proc_cells_lock);
-
-	if (root) {
-		struct hlist_node *n;
-		inode_lock(root->d_inode);
-
-		/* Remove all the pins for dirs created for manually added cells */
-		hlist_for_each_entry_safe(subdir, n, &root->d_children, d_sib) {
-			if (subdir->d_fsdata) {
-				subdir->d_fsdata = NULL;
-				dput(subdir);
-			}
-		}
+	struct afs_super_info *as = AFS_FS_S(sb);
+	struct afs_vnode *vnode;
+	struct inode *inode;
+	struct afs_fid fid = { .vid = 0, .vnode = 1, .unique = 1,};
+
+	if (as->volume)
+		fid.vid = as->volume->vid;
 
-		inode_unlock(root->d_inode);
+	inode = iget5_locked(sb, fid.vnode,
+			     afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	vnode = AFS_FS_I(inode);
+
+	/* there shouldn't be an existing inode */
+	if (inode->i_state & I_NEW) {
+		netfs_inode_init(&vnode->netfs, NULL, false);
+		simple_inode_init_ts(inode);
+		set_nlink(inode, 2);
+		inode->i_size		= 0;
+		inode->i_mode		= S_IFDIR | 0555;
+		inode->i_op		= &afs_dynroot_inode_operations;
+		inode->i_fop		= &afs_dynroot_file_operations;
+		inode->i_uid		= GLOBAL_ROOT_UID;
+		inode->i_gid		= GLOBAL_ROOT_GID;
+		inode->i_blocks		= 0;
+		inode->i_generation	= 0;
+		inode->i_flags		|= S_NOATIME;
+
+		set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
+		unlock_new_inode(inode);
 	}
+	_leave(" = %p", inode);
+	return inode;
 }
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index aa66d8010f8942..f9b90e59659317 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -302,6 +302,7 @@ struct afs_net {
 
 	/* Cell database */
 	struct rb_root		cells;
+	struct idr		cells_dyn_ino;	/* cell->dynroot_ino mapping */
 	struct afs_cell __rcu	*ws_cell;
 	struct work_struct	cells_manager;
 	struct timer_list	cells_timer;
@@ -413,6 +414,7 @@ struct afs_cell {
 	enum dns_lookup_status	dns_status:8;	/* Latest status of data from lookup */
 	unsigned int		dns_lookup_count; /* Counter of DNS lookups */
 	unsigned int		debug_id;
+	unsigned int		dynroot_ino;	/* Inode numbers for dynroot (a pair) */
 
 	/* The volumes belonging to this cell */
 	struct rw_semaphore	vs_lock;	/* Lock for server->volumes */
@@ -1088,10 +1090,7 @@ extern int afs_silly_iput(struct dentry *, struct inode *);
 extern const struct inode_operations afs_dynroot_inode_operations;
 extern const struct dentry_operations afs_dynroot_dentry_operations;
 
-extern int afs_dynroot_mkdir(struct afs_net *, struct afs_cell *);
-extern void afs_dynroot_rmdir(struct afs_net *, struct afs_cell *);
-extern int afs_dynroot_populate(struct super_block *);
-extern void afs_dynroot_depopulate(struct super_block *);
+struct inode *afs_dynroot_iget_root(struct super_block *sb);
 
 /*
  * file.c
@@ -1206,7 +1205,6 @@ extern const struct afs_operation_ops afs_fetch_status_operation;
 extern void afs_vnode_commit_status(struct afs_operation *, struct afs_vnode_param *);
 extern int afs_fetch_status(struct afs_vnode *, struct key *, bool, afs_access_t *);
 extern int afs_ilookup5_test_by_fid(struct inode *, void *);
-extern struct inode *afs_iget_pseudo_dir(struct super_block *, bool);
 extern struct inode *afs_iget(struct afs_operation *, struct afs_vnode_param *);
 extern struct inode *afs_root_iget(struct super_block *, struct key *);
 extern int afs_getattr(struct mnt_idmap *idmap, const struct path *,
diff --git a/fs/afs/main.c b/fs/afs/main.c
index a14f6013e316d9..5fffbc4d47aff5 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -76,6 +76,7 @@ static int __net_init afs_net_init(struct net *net_ns)
 	mutex_init(&net->socket_mutex);
 
 	net->cells = RB_ROOT;
+	idr_init(&net->cells_dyn_ino);
 	init_rwsem(&net->cells_lock);
 	INIT_WORK(&net->cells_manager, afs_manage_cells);
 	timer_setup(&net->cells_timer, afs_cells_timer, 0);
@@ -137,6 +138,7 @@ static int __net_init afs_net_init(struct net *net_ns)
 error_proc:
 	afs_put_sysnames(net->sysnames);
 error_sysnames:
+	idr_destroy(&net->cells_dyn_ino);
 	net->live = false;
 	return ret;
 }
@@ -155,6 +157,7 @@ static void __net_exit afs_net_exit(struct net *net_ns)
 	afs_close_socket(net);
 	afs_proc_cleanup(net);
 	afs_put_sysnames(net->sysnames);
+	idr_destroy(&net->cells_dyn_ino);
 	kfree_rcu(rcu_access_pointer(net->address_prefs), rcu);
 }
 
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 259c48e37537eb..e03540dbd62b07 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -466,7 +466,7 @@ static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
 
 	/* allocate the root inode and dentry */
 	if (as->dyn_root) {
-		inode = afs_iget_pseudo_dir(sb, true);
+		inode = afs_dynroot_iget_root(sb);
 	} else {
 		sprintf(sb->s_id, "%llu", as->volume->vid);
 		afs_activate_volume(as->volume);
@@ -483,9 +483,6 @@ static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
 
 	if (as->dyn_root) {
 		sb->s_d_op = &afs_dynroot_dentry_operations;
-		ret = afs_dynroot_populate(sb);
-		if (ret < 0)
-			goto error;
 	} else {
 		sb->s_d_op = &afs_fs_dentry_operations;
 		rcu_assign_pointer(as->volume->sb, sb);
@@ -534,9 +531,6 @@ static void afs_kill_super(struct super_block *sb)
 {
 	struct afs_super_info *as = AFS_FS_S(sb);
 
-	if (as->dyn_root)
-		afs_dynroot_depopulate(sb);
-
 	/* Clear the callback interests (which will do ilookup5) before
 	 * deactivating the superblock.
 	 */
diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index 27bac4d5ac906e..4fcfb2411f9df2 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -190,8 +190,10 @@ enum yfs_cm_operation {
 	EM(afs_cell_trace_unuse_alias,		"UNU alias ") \
 	EM(afs_cell_trace_unuse_check_alias,	"UNU chk-al") \
 	EM(afs_cell_trace_unuse_delete,		"UNU delete") \
+	EM(afs_cell_trace_unuse_dynroot_mntpt,	"UNU dyn-mp") \
 	EM(afs_cell_trace_unuse_fc,		"UNU fc    ") \
 	EM(afs_cell_trace_unuse_lookup,		"UNU lookup") \
+	EM(afs_cell_trace_unuse_lookup_dynroot,	"UNU lu-dyn") \
 	EM(afs_cell_trace_unuse_mntpt,		"UNU mntpt ") \
 	EM(afs_cell_trace_unuse_no_pin,		"UNU no-pin") \
 	EM(afs_cell_trace_unuse_parse,		"UNU parse ") \
-- 
2.53.0

[PATCH 6.12 0745/1276] netfs: Fix writeback error handling

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit ac5f95ac5d6d0f4c567b8b642825705a2bf0d79e ]

Fix the error handling in writeback_iter() loop.  If an error occurs,
writeback_iter() needs to be called again with *error set to the error so
that it can clean up iteration state.  Further, the current folio needs
unlocking and redirtying.

Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Link: https://sashiko.dev/#/patchset/20260619140646.2633762-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260625140640.3116900-14-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/write_issue.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 2789ac4c80272b..7431c0a4252c4c 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -574,8 +574,6 @@ int netfs_writepages(struct address_space *mapping,
 		}
 
 		error = netfs_write_folio(wreq, wbc, folio);
-		if (error < 0)
-			break;
 	} while ((folio = writeback_iter(mapping, wbc, folio, &error)));
 
 	netfs_end_issue_write(wreq);
@@ -587,7 +585,14 @@ int netfs_writepages(struct address_space *mapping,
 	return error;
 
 couldnt_start:
-	netfs_kill_dirty_pages(mapping, wbc, folio);
+	if (error == -ENOMEM) {
+		folio_redirty_for_writepage(wbc, folio);
+		folio_unlock(folio);
+		folio = writeback_iter(mapping, wbc, folio, &error);
+		WARN_ON_ONCE(folio != NULL);
+	} else {
+		netfs_kill_dirty_pages(mapping, wbc, folio);
+	}
 out:
 	mutex_unlock(&ictx->wb_lock);
 	_leave(" = %d", error);
-- 
2.53.0

[PATCH 6.12 0749/1276] netfs: Drop the error arg from netfs_read_subreq_terminated()

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 360157829ee3dba848ffa817792d9a07969e0a95 ]

Drop the error argument from netfs_read_subreq_terminated() in favour of
passing the value in subreq->error.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-9-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: c16b8c4cfb4f ("cifs: Fix missing credit release on failure in cifs_issue_read()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/9p/vfs_addr.c         |  3 ++-
 fs/afs/file.c            | 15 ++++++++-----
 fs/ceph/addr.c           | 13 +++++++----
 fs/netfs/buffered_read.c | 16 +++++++-------
 fs/netfs/objects.c       | 15 ++++++++++++-
 fs/netfs/read_collect.c  | 47 +++++++++++++++++++++++++---------------
 fs/nfs/fscache.c         |  6 +++--
 fs/nfs/fscache.h         |  3 ++-
 fs/smb/client/cifssmb.c  | 10 +--------
 fs/smb/client/file.c     |  3 ++-
 fs/smb/client/smb2pdu.c  | 10 +--------
 include/linux/netfs.h    |  7 +++---
 12 files changed, 86 insertions(+), 62 deletions(-)

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index db78c06ba0cc6f..d6107ac50e8821 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -83,7 +83,8 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
 	if (!err)
 		subreq->transferred += total;
 
-	netfs_read_subreq_terminated(subreq, err, false);
+	subreq->error = err;
+	netfs_read_subreq_terminated(subreq, false);
 }
 
 /**
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 6762eff9751722..56248a078bcaa6 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -246,7 +246,8 @@ static void afs_fetch_data_notify(struct afs_operation *op)
 		subreq->rreq->i_size = req->file_size;
 		if (req->pos + req->actual_len >= req->file_size)
 			__set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags);
-		netfs_read_subreq_terminated(subreq, error, false);
+		subreq->error = error;
+		netfs_read_subreq_terminated(subreq, false);
 		req->subreq = NULL;
 	} else if (req->done) {
 		req->done(req);
@@ -301,8 +302,10 @@ int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
 
 	op = afs_alloc_operation(req->key, vnode->volume);
 	if (IS_ERR(op)) {
-		if (req->subreq)
-			netfs_read_subreq_terminated(req->subreq, PTR_ERR(op), false);
+		if (req->subreq) {
+			req->subreq->error = PTR_ERR(op);
+			netfs_read_subreq_terminated(req->subreq, false);
+		}
 		return PTR_ERR(op);
 	}
 
@@ -320,8 +323,10 @@ static void afs_read_worker(struct work_struct *work)
 	struct afs_read *fsreq;
 
 	fsreq = afs_alloc_read(GFP_NOFS);
-	if (!fsreq)
-		return netfs_read_subreq_terminated(subreq, -ENOMEM, false);
+	if (!fsreq) {
+		subreq->error = -ENOMEM;
+		return netfs_read_subreq_terminated(subreq, false);
+	}
 
 	fsreq->subreq	= subreq;
 	fsreq->pos	= subreq->start + subreq->transferred;
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 5addf09cb6e6ee..8d1a646e229a56 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -253,8 +253,9 @@ static void finish_netfs_read(struct ceph_osd_request *req)
 		subreq->transferred = err;
 		err = 0;
 	}
+	subreq->error = err;
 	trace_netfs_sreq(subreq, netfs_sreq_trace_io_progress);
-	netfs_read_subreq_terminated(subreq, err, false);
+	netfs_read_subreq_terminated(subreq, false);
 	iput(req->r_inode);
 	ceph_dec_osd_stopping_blocker(fsc->mdsc);
 }
@@ -314,7 +315,9 @@ static bool ceph_netfs_issue_op_inline(struct netfs_io_subrequest *subreq)
 
 	ceph_mdsc_put_request(req);
 out:
-	netfs_read_subreq_terminated(subreq, err, false);
+	subreq->error = err;
+	trace_netfs_sreq(subreq, netfs_sreq_trace_io_progress);
+	netfs_read_subreq_terminated(subreq, false);
 	return true;
 }
 
@@ -435,8 +438,10 @@ static void ceph_netfs_issue_read(struct netfs_io_subrequest *subreq)
 	ceph_osdc_start_request(req->r_osdc, req);
 out:
 	ceph_osdc_put_request(req);
-	if (err)
-		netfs_read_subreq_terminated(subreq, err, false);
+	if (err) {
+		subreq->error = err;
+		netfs_read_subreq_terminated(subreq, false);
+	}
 	doutc(cl, "%llx.%llx result %d\n", ceph_vinop(inode), err);
 }
 
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 3b418fed46027c..5f3073ad42085a 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -190,14 +190,13 @@ static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error
 {
 	struct netfs_io_subrequest *subreq = priv;
 
-	if (transferred_or_error < 0) {
-		netfs_read_subreq_terminated(subreq, transferred_or_error, was_async);
-		return;
-	}
-
-	if (transferred_or_error > 0)
+	if (transferred_or_error > 0) {
 		subreq->transferred += transferred_or_error;
-	netfs_read_subreq_terminated(subreq, 0, was_async);
+		subreq->error = 0;
+	} else {
+		subreq->error = transferred_or_error;
+	}
+	netfs_read_subreq_terminated(subreq, was_async);
 }
 
 /*
@@ -297,7 +296,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)
 			if (slice < 0)
 				goto prep_iter_failed;
 			__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
-			netfs_read_subreq_terminated(subreq, 0, false);
+			subreq->error = 0;
+			netfs_read_subreq_terminated(subreq, false);
 			goto done;
 		}
 
diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c
index 31e388ec6e4875..eb8411bd0a7431 100644
--- a/fs/netfs/objects.c
+++ b/fs/netfs/objects.c
@@ -191,7 +191,20 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq
 	}
 
 	memset(subreq, 0, kmem_cache_size(cache));
-	INIT_WORK(&subreq->work, NULL);
+
+	switch (rreq->origin) {
+	case NETFS_READAHEAD:
+	case NETFS_READPAGE:
+	case NETFS_READ_GAPS:
+	case NETFS_READ_FOR_WRITE:
+	case NETFS_DIO_READ:
+		INIT_WORK(&subreq->work, netfs_read_subreq_termination_worker);
+		break;
+	default:
+		INIT_WORK(&subreq->work, NULL);
+		break;
+	}
+
 	INIT_LIST_HEAD(&subreq->rreq_link);
 	refcount_set(&subreq->ref, 2);
 	subreq->rreq = rreq;
diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c
index eae415efae24a0..2955dc31d3c771 100644
--- a/fs/netfs/read_collect.c
+++ b/fs/netfs/read_collect.c
@@ -449,28 +449,26 @@ EXPORT_SYMBOL(netfs_read_subreq_progress);
 /**
  * netfs_read_subreq_terminated - Note the termination of an I/O operation.
  * @subreq: The I/O request that has terminated.
- * @error: Error code indicating type of completion.
- * @was_async: The termination was asynchronous
+ * @was_async: True if we're in an asynchronous context.
  *
  * This tells the read helper that a contributory I/O operation has terminated,
  * one way or another, and that it should integrate the results.
  *
- * The caller indicates the outcome of the operation through @error, supplying
- * 0 to indicate a successful or retryable transfer (if NETFS_SREQ_NEED_RETRY
- * is set) or a negative error code.  The helper will look after reissuing I/O
- * operations as appropriate and writing downloaded data to the cache.
+ * The caller indicates the outcome of the operation through @subreq->error,
+ * supplying 0 to indicate a successful or retryable transfer (if
+ * NETFS_SREQ_NEED_RETRY is set) or a negative error code.  The helper will
+ * look after reissuing I/O operations as appropriate and writing downloaded
+ * data to the cache.
  *
  * Before calling, the filesystem should update subreq->transferred to track
  * the amount of data copied into the output buffer.
- *
- * If @was_async is true, the caller might be running in softirq or interrupt
- * context and we can't sleep.
  */
-void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq,
-				  int error, bool was_async)
+void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq, bool was_async)
 {
 	struct netfs_io_request *rreq = subreq->rreq;
 
+	might_sleep();
+
 	switch (subreq->source) {
 	case NETFS_READ_FROM_CACHE:
 		netfs_stat(&netfs_n_rh_read_done);
@@ -488,7 +486,7 @@ void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq,
 		 * If the read completed validly short, then we can clear the
 		 * tail before going on to unlock the folios.
 		 */
-		if (error == 0 && subreq->transferred < subreq->len &&
+		if (subreq->error == 0 && subreq->transferred < subreq->len &&
 		    (test_bit(NETFS_SREQ_HIT_EOF, &subreq->flags) ||
 		     test_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags))) {
 			netfs_clear_unread(subreq);
@@ -508,7 +506,7 @@ void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq,
 	/* Deal with retry requests, short reads and errors.  If we retry
 	 * but don't make progress, we abandon the attempt.
 	 */
-	if (!error && subreq->transferred < subreq->len) {
+	if (!subreq->error && subreq->transferred < subreq->len) {
 		if (test_bit(NETFS_SREQ_HIT_EOF, &subreq->flags)) {
 			trace_netfs_sreq(subreq, netfs_sreq_trace_hit_eof);
 		} else {
@@ -522,16 +520,15 @@ void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq,
 				set_bit(NETFS_RREQ_NEED_RETRY, &rreq->flags);
 			} else {
 				__set_bit(NETFS_SREQ_FAILED, &subreq->flags);
-				error = -ENODATA;
+				subreq->error = -ENODATA;
 			}
 		}
 	}
 
-	subreq->error = error;
 	trace_netfs_sreq(subreq, netfs_sreq_trace_terminated);
 
-	if (unlikely(error < 0)) {
-		trace_netfs_failure(rreq, subreq, error, netfs_fail_read);
+	if (unlikely(subreq->error < 0)) {
+		trace_netfs_failure(rreq, subreq, subreq->error, netfs_fail_read);
 		if (subreq->source == NETFS_READ_FROM_CACHE) {
 			netfs_stat(&netfs_n_rh_read_failed);
 		} else {
@@ -547,3 +544,19 @@ void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq,
 	netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated);
 }
 EXPORT_SYMBOL(netfs_read_subreq_terminated);
+
+/**
+ * netfs_read_subreq_termination_worker - Workqueue helper for read termination
+ * @work: The subreq->work in the I/O request that has been terminated.
+ *
+ * Helper function to jump to netfs_read_subreq_terminated() from the
+ * subrequest work item.
+ */
+void netfs_read_subreq_termination_worker(struct work_struct *work)
+{
+	struct netfs_io_subrequest *subreq =
+		container_of(work, struct netfs_io_subrequest, work);
+
+	netfs_read_subreq_terminated(subreq, false);
+}
+EXPORT_SYMBOL(netfs_read_subreq_termination_worker);
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index d49e4ce279994f..be14d30608f6d5 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -314,8 +314,10 @@ static void nfs_netfs_issue_read(struct netfs_io_subrequest *sreq)
 			     &nfs_async_read_completion_ops);
 
 	netfs = nfs_netfs_alloc(sreq);
-	if (!netfs)
-		return netfs_read_subreq_terminated(sreq, -ENOMEM, false);
+	if (!netfs) {
+		sreq->error = -ENOMEM;
+		return netfs_read_subreq_terminated(sreq, false);
+	}
 
 	pgio.pg_netfs = netfs; /* used in completion */
 
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index 772d485e96d35a..1d86f7cc719507 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -74,7 +74,8 @@ static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs)
 	 */
 	netfs->sreq->transferred = min_t(s64, netfs->sreq->len,
 					 atomic64_read(&netfs->transferred));
-	netfs_read_subreq_terminated(netfs->sreq, netfs->error, false);
+	netfs->sreq->error = netfs->error;
+	netfs_read_subreq_terminated(netfs->sreq, false);
 	kfree(netfs);
 }
 static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi)
diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index 8a257cb29c955e..81a1c116e90317 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -1262,14 +1262,6 @@ CIFS_open(const unsigned int xid, struct cifs_open_parms *oparms, int *oplock,
 	return rc;
 }
 
-static void cifs_readv_worker(struct work_struct *work)
-{
-	struct cifs_io_subrequest *rdata =
-		container_of(work, struct cifs_io_subrequest, subreq.work);
-
-	netfs_read_subreq_terminated(&rdata->subreq, rdata->result, false);
-}
-
 static void
 cifs_readv_callback(struct mid_q_entry *mid)
 {
@@ -1336,8 +1328,8 @@ cifs_readv_callback(struct mid_q_entry *mid)
 	}
 
 	rdata->credits.value = 0;
+	rdata->subreq.error = rdata->result;
 	rdata->subreq.transferred += rdata->got_bytes;
-	INIT_WORK(&rdata->subreq.work, cifs_readv_worker);
 	queue_work(cifsiod_wq, &rdata->subreq.work);
 	release_mid(mid);
 	add_credits(server, &credits, 0);
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 53349f2118cda6..898fb7e293ddc7 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -229,7 +229,8 @@ static void cifs_issue_read(struct netfs_io_subrequest *subreq)
 	return;
 
 failed:
-	netfs_read_subreq_terminated(subreq, rc, false);
+	subreq->error = rc;
+	netfs_read_subreq_terminated(subreq, false);
 }
 
 /*
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 7fc588eabb2234..5a8a9e4ba36db9 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4536,14 +4536,6 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
 	return rc;
 }
 
-static void smb2_readv_worker(struct work_struct *work)
-{
-	struct cifs_io_subrequest *rdata =
-		container_of(work, struct cifs_io_subrequest, subreq.work);
-
-	netfs_read_subreq_terminated(&rdata->subreq, rdata->result, false);
-}
-
 static void
 smb2_readv_callback(struct mid_q_entry *mid)
 {
@@ -4656,9 +4648,9 @@ smb2_readv_callback(struct mid_q_entry *mid)
 			      server->credits, server->in_flight,
 			      0, cifs_trace_rw_credits_read_response_clear);
 	rdata->credits.value = 0;
+	rdata->subreq.error = rdata->result;
 	rdata->subreq.transferred += rdata->got_bytes;
 	trace_netfs_sreq(&rdata->subreq, netfs_sreq_trace_io_progress);
-	INIT_WORK(&rdata->subreq.work, smb2_readv_worker);
 	queue_work(cifsiod_wq, &rdata->subreq.work);
 	release_mid(mid);
 	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, 0,
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 83d313718cd509..6bd0dbfe8f0c9d 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -429,10 +429,9 @@ bool netfs_release_folio(struct folio *folio, gfp_t gfp);
 vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group);
 
 /* (Sub)request management API. */
-void netfs_read_subreq_progress(struct netfs_io_subrequest *subreq,
-				bool was_async);
-void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq,
-				  int error, bool was_async);
+void netfs_read_subreq_progress(struct netfs_io_subrequest *subreq, bool was_async);
+void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq, bool was_async);
+void netfs_read_subreq_termination_worker(struct work_struct *work);
 void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
 			  enum netfs_sreq_ref_trace what);
 void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
-- 
2.53.0

[PATCH 6.12 0750/1276] cifs: Fix missing credit release on failure in cifs_issue_read()

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit c16b8c4cfb4fe2244cc33e469a93c1ab8684146b ]

Fix missing release of credits in the failure path in cifs_issue_read()
lest retrying the subreq just overwrites the credits value.

Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks")
Link: https://sashiko.dev/#/patchset/20260608145432.681865-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 898fb7e293ddc7..70b64df9fb2ebf 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -229,6 +229,7 @@ static void cifs_issue_read(struct netfs_io_subrequest *subreq)
 	return;
 
 failed:
+	add_credits_and_wake_if(rdata->server, &rdata->credits, 0);
 	subreq->error = rc;
 	netfs_read_subreq_terminated(subreq, false);
 }
-- 
2.53.0

[PATCH 6.12 1200/1276] hfs/hfsplus: prevent getting negative values of offset/length

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Viacheslav Dubeyko <slava@dubeyko.com>

[ Upstream commit 00c14a09a70e10ae18eb3707d0059291425c04bd ]

The syzbot reported KASAN out-of-bounds issue in
hfs_bnode_move():

[   45.588165][ T9821] hfs: dst 14, src 65536, len -65536
[   45.588895][ T9821] ==================================================================
[   45.590114][ T9821] BUG: KASAN: out-of-bounds in hfs_bnode_move+0xfd/0x140
[   45.591127][ T9821] Read of size 18446744073709486080 at addr ffff888035935400 by task repro/9821
[   45.592207][ T9821]
[   45.592420][ T9821] CPU: 0 UID: 0 PID: 9821 Comm: repro Not tainted 6.16.0-rc7-dirty #42 PREEMPT(full)
[   45.592428][ T9821] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   45.592431][ T9821] Call Trace:
[   45.592434][ T9821]  <TASK>
[   45.592437][ T9821]  dump_stack_lvl+0x1c1/0x2a0
[   45.592446][ T9821]  ? __virt_addr_valid+0x1c8/0x5c0
[   45.592454][ T9821]  ? __pfx_dump_stack_lvl+0x10/0x10
[   45.592461][ T9821]  ? rcu_is_watching+0x15/0xb0
[   45.592469][ T9821]  ? lock_release+0x4b/0x3e0
[   45.592476][ T9821]  ? __virt_addr_valid+0x1c8/0x5c0
[   45.592483][ T9821]  ? __virt_addr_valid+0x4a5/0x5c0
[   45.592491][ T9821]  print_report+0x17e/0x7c0
[   45.592497][ T9821]  ? __virt_addr_valid+0x1c8/0x5c0
[   45.592504][ T9821]  ? __virt_addr_valid+0x4a5/0x5c0
[   45.592511][ T9821]  ? __phys_addr+0xd3/0x180
[   45.592519][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592526][ T9821]  kasan_report+0x147/0x180
[   45.592531][ T9821]  ? _printk+0xcf/0x120
[   45.592537][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592544][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592552][ T9821]  kasan_check_range+0x2b0/0x2c0
[   45.592557][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592565][ T9821]  __asan_memmove+0x29/0x70
[   45.592572][ T9821]  hfs_bnode_move+0xfd/0x140
[   45.592580][ T9821]  hfs_brec_remove+0x473/0x560
[   45.592589][ T9821]  hfs_cat_move+0x6fb/0x960
[   45.592598][ T9821]  ? __pfx_hfs_cat_move+0x10/0x10
[   45.592607][ T9821]  ? seqcount_lockdep_reader_access+0x122/0x1c0
[   45.592614][ T9821]  ? lockdep_hardirqs_on+0x9c/0x150
[   45.592631][ T9821]  ? __lock_acquire+0xaec/0xd80
[   45.592641][ T9821]  hfs_rename+0x1dc/0x2d0
[   45.592649][ T9821]  ? __pfx_hfs_rename+0x10/0x10
[   45.592657][ T9821]  vfs_rename+0xac6/0xed0
[   45.592664][ T9821]  ? __pfx_vfs_rename+0x10/0x10
[   45.592670][ T9821]  ? d_alloc+0x144/0x190
[   45.592677][ T9821]  ? bpf_lsm_path_rename+0x9/0x20
[   45.592683][ T9821]  ? security_path_rename+0x17d/0x490
[   45.592691][ T9821]  do_renameat2+0x890/0xc50
[   45.592699][ T9821]  ? __pfx_do_renameat2+0x10/0x10
[   45.592707][ T9821]  ? getname_flags+0x1e5/0x540
[   45.592714][ T9821]  __x64_sys_rename+0x82/0x90
[   45.592720][ T9821]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   45.592725][ T9821]  do_syscall_64+0xf3/0x3a0
[   45.592741][ T9821]  ? exc_page_fault+0x9f/0xf0
[   45.592748][ T9821]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   45.592754][ T9821] RIP: 0033:0x7f7f73fe3fc9
[   45.592760][ T9821] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 48
[   45.592765][ T9821] RSP: 002b:00007ffc7e116cf8 EFLAGS: 00000283 ORIG_RAX: 0000000000000052
[   45.592772][ T9821] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7f73fe3fc9
[   45.592776][ T9821] RDX: 0000200000000871 RSI: 0000200000000780 RDI: 00002000000003c0
[   45.592781][ T9821] RBP: 00007ffc7e116d00 R08: 0000000000000000 R09: 00007ffc7e116d30
[   45.592784][ T9821] R10: fffffffffffffff0 R11: 0000000000000283 R12: 00005557e81f8250
[   45.592788][ T9821] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   45.592795][ T9821]  </TASK>
[   45.592797][ T9821]
[   45.619721][ T9821] The buggy address belongs to the physical page:
[   45.620300][ T9821] page: refcount:1 mapcount:1 mapping:0000000000000000 index:0x559a88174 pfn:0x35935
[   45.621150][ T9821] memcg:ffff88810a1d5b00
[   45.621531][ T9821] anon flags: 0xfff60000020838(uptodate|dirty|lru|owner_2|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
[   45.622496][ T9821] raw: 00fff60000020838 ffffea0000d64d88 ffff888021753e10 ffff888029da0771
[   45.623260][ T9821] raw: 0000000559a88174 0000000000000000 0000000100000000 ffff88810a1d5b00
[   45.624030][ T9821] page dumped because: kasan: bad access detected
[   45.624602][ T9821] page_owner tracks the page as allocated
[   45.625115][ T9821] page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO0
[   45.626685][ T9821]  post_alloc_hook+0x240/0x2a0
[   45.627127][ T9821]  get_page_from_freelist+0x2101/0x21e0
[   45.627628][ T9821]  __alloc_frozen_pages_noprof+0x274/0x380
[   45.628154][ T9821]  alloc_pages_mpol+0x241/0x4b0
[   45.628593][ T9821]  vma_alloc_folio_noprof+0xe4/0x210
[   45.629066][ T9821]  folio_prealloc+0x30/0x180
[   45.629487][ T9821]  __handle_mm_fault+0x34bd/0x5640
[   45.629957][ T9821]  handle_mm_fault+0x40e/0x8e0
[   45.630392][ T9821]  do_user_addr_fault+0xa81/0x1390
[   45.630862][ T9821]  exc_page_fault+0x76/0xf0
[   45.631273][ T9821]  asm_exc_page_fault+0x26/0x30
[   45.631712][ T9821] page last free pid 5269 tgid 5269 stack trace:
[   45.632281][ T9821]  free_unref_folios+0xc73/0x14c0
[   45.632740][ T9821]  folios_put_refs+0x55b/0x640
[   45.633177][ T9821]  free_pages_and_swap_cache+0x26d/0x510
[   45.633685][ T9821]  tlb_flush_mmu+0x3a0/0x680
[   45.634105][ T9821]  tlb_finish_mmu+0xd4/0x200
[   45.634525][ T9821]  exit_mmap+0x44c/0xb70
[   45.634914][ T9821]  __mmput+0x118/0x420
[   45.635286][ T9821]  exit_mm+0x1da/0x2c0
[   45.635659][ T9821]  do_exit+0x652/0x2330
[   45.636039][ T9821]  do_group_exit+0x21c/0x2d0
[   45.636457][ T9821]  __x64_sys_exit_group+0x3f/0x40
[   45.636915][ T9821]  x64_sys_call+0x21ba/0x21c0
[   45.637342][ T9821]  do_syscall_64+0xf3/0x3a0
[   45.637756][ T9821]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   45.638290][ T9821] page has been migrated, last migrate reason: numa_misplaced
[   45.638956][ T9821]
[   45.639173][ T9821] Memory state around the buggy address:
[   45.639677][ T9821]  ffff888035935300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.640397][ T9821]  ffff888035935380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.641117][ T9821] >ffff888035935400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.641837][ T9821]                    ^
[   45.642207][ T9821]  ffff888035935480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.642929][ T9821]  ffff888035935500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.643650][ T9821] ==================================================================

This commit [1] fixes the issue if an offset inside of b-tree node
or length of the request is bigger than b-tree node. However,
this fix is still not ready for negative values
of the offset or length. Moreover, negative values of
the offset or length doesn't make sense for b-tree's
operations. Because we could try to access the memory address
outside of the beginning of memory page's addresses range.
Also, using of negative values make logic very complicated,
unpredictable, and we could access the wrong item(s)
in the b-tree node.

This patch changes b-tree interface by means of converting
signed integer arguments of offset and length on u32 type.
Such conversion has goal to prevent of using negative values
unintentionally or by mistake in b-tree operations.

[1] 'commit a431930c9bac ("hfs: fix slab-out-of-bounds in hfs_bnode_read()")'

Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20251002200020.2578311-1-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Stable-dep-of: 966cb76fb285 ("hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/hfs/bfind.c          |    2 -
 fs/hfs/bnode.c          |   52 ++++++++++++++--------------
 fs/hfs/brec.c           |    2 -
 fs/hfs/btree.c          |    2 -
 fs/hfs/btree.h          |   71 +++++++++++++++++++-------------------
 fs/hfs/hfs_fs.h         |   88 ++++++++++++++++++++++++++++--------------------
 fs/hfs/inode.c          |    3 +
 fs/hfsplus/bfind.c      |    2 -
 fs/hfsplus/bnode.c      |   60 ++++++++++++++++----------------
 fs/hfsplus/brec.c       |    2 -
 fs/hfsplus/btree.c      |    2 -
 fs/hfsplus/hfsplus_fs.h |   38 ++++++++++----------
 12 files changed, 171 insertions(+), 153 deletions(-)

--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -167,7 +167,7 @@ release:
 	return res;
 }
 
-int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
+int hfs_brec_read(struct hfs_find_data *fd, void *rec, u32 rec_len)
 {
 	int res;
 
--- a/fs/hfs/bnode.c
+++ b/fs/hfs/bnode.c
@@ -16,14 +16,14 @@
 #include "btree.h"
 
 static inline
-bool is_bnode_offset_valid(struct hfs_bnode *node, int off)
+bool is_bnode_offset_valid(struct hfs_bnode *node, u32 off)
 {
 	bool is_valid = off < node->tree->node_size;
 
 	if (!is_valid) {
 		pr_err("requested invalid offset: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d\n",
+		       "node_size %u, offset %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off);
 	}
@@ -32,7 +32,7 @@ bool is_bnode_offset_valid(struct hfs_bn
 }
 
 static inline
-int check_and_correct_requested_length(struct hfs_bnode *node, int off, int len)
+u32 check_and_correct_requested_length(struct hfs_bnode *node, u32 off, u32 len)
 {
 	unsigned int node_size;
 
@@ -42,12 +42,12 @@ int check_and_correct_requested_length(s
 	node_size = node->tree->node_size;
 
 	if ((off + len) > node_size) {
-		int new_len = (int)node_size - off;
+		u32 new_len = node_size - off;
 
 		pr_err("requested length has been corrected: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, "
-		       "requested_len %d, corrected_len %d\n",
+		       "node_size %u, offset %u, "
+		       "requested_len %u, corrected_len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len, new_len);
 
@@ -57,12 +57,12 @@ int check_and_correct_requested_length(s
 	return len;
 }
 
-void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
+void hfs_bnode_read(struct hfs_bnode *node, void *buf, u32 off, u32 len)
 {
 	struct page *page;
-	int pagenum;
-	int bytes_read;
-	int bytes_to_read;
+	u32 pagenum;
+	u32 bytes_read;
+	u32 bytes_to_read;
 
 	memset(buf, 0, len);
 
@@ -72,7 +72,7 @@ void hfs_bnode_read(struct hfs_bnode *no
 	if (len == 0) {
 		pr_err("requested zero length: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, len %d\n",
+		       "node_size %u, offset %u, len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len);
 		return;
@@ -88,7 +88,7 @@ void hfs_bnode_read(struct hfs_bnode *no
 		if (pagenum >= node->tree->pages_per_bnode)
 			break;
 		page = node->page[pagenum];
-		bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off);
+		bytes_to_read = min_t(u32, len - bytes_read, PAGE_SIZE - off);
 
 		memcpy_from_page(buf + bytes_read, page, off, bytes_to_read);
 
@@ -97,7 +97,7 @@ void hfs_bnode_read(struct hfs_bnode *no
 	}
 }
 
-u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
+u16 hfs_bnode_read_u16(struct hfs_bnode *node, u32 off)
 {
 	__be16 data;
 	// optimize later...
@@ -105,7 +105,7 @@ u16 hfs_bnode_read_u16(struct hfs_bnode
 	return be16_to_cpu(data);
 }
 
-u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
+u8 hfs_bnode_read_u8(struct hfs_bnode *node, u32 off)
 {
 	u8 data;
 	// optimize later...
@@ -113,10 +113,10 @@ u8 hfs_bnode_read_u8(struct hfs_bnode *n
 	return data;
 }
 
-void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
+void hfs_bnode_read_key(struct hfs_bnode *node, void *key, u32 off)
 {
 	struct hfs_btree *tree;
-	int key_len;
+	u32 key_len;
 
 	tree = node->tree;
 	if (node->type == HFS_NODE_LEAF ||
@@ -127,14 +127,14 @@ void hfs_bnode_read_key(struct hfs_bnode
 
 	if (key_len > sizeof(hfs_btree_key) || key_len < 1) {
 		memset(key, 0, sizeof(hfs_btree_key));
-		pr_err("hfs: Invalid key length: %d\n", key_len);
+		pr_err("hfs: Invalid key length: %u\n", key_len);
 		return;
 	}
 
 	hfs_bnode_read(node, key, off, key_len);
 }
 
-void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
+void hfs_bnode_write(struct hfs_bnode *node, void *buf, u32 off, u32 len)
 {
 	struct page *page;
 
@@ -144,7 +144,7 @@ void hfs_bnode_write(struct hfs_bnode *n
 	if (len == 0) {
 		pr_err("requested zero length: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, len %d\n",
+		       "node_size %u, offset %u, len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len);
 		return;
@@ -159,20 +159,20 @@ void hfs_bnode_write(struct hfs_bnode *n
 	set_page_dirty(page);
 }
 
-void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
+void hfs_bnode_write_u16(struct hfs_bnode *node, u32 off, u16 data)
 {
 	__be16 v = cpu_to_be16(data);
 	// optimize later...
 	hfs_bnode_write(node, &v, off, 2);
 }
 
-void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data)
+void hfs_bnode_write_u8(struct hfs_bnode *node, u32 off, u8 data)
 {
 	// optimize later...
 	hfs_bnode_write(node, &data, off, 1);
 }
 
-void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
+void hfs_bnode_clear(struct hfs_bnode *node, u32 off, u32 len)
 {
 	struct page *page;
 
@@ -182,7 +182,7 @@ void hfs_bnode_clear(struct hfs_bnode *n
 	if (len == 0) {
 		pr_err("requested zero length: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, len %d\n",
+		       "node_size %u, offset %u, len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len);
 		return;
@@ -197,8 +197,8 @@ void hfs_bnode_clear(struct hfs_bnode *n
 	set_page_dirty(page);
 }
 
-void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
-		struct hfs_bnode *src_node, int src, int len)
+void hfs_bnode_copy(struct hfs_bnode *dst_node, u32 dst,
+		    struct hfs_bnode *src_node, u32 src, u32 len)
 {
 	struct page *src_page, *dst_page;
 
@@ -218,7 +218,7 @@ void hfs_bnode_copy(struct hfs_bnode *ds
 	set_page_dirty(dst_page);
 }
 
-void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
+void hfs_bnode_move(struct hfs_bnode *node, u32 dst, u32 src, u32 len)
 {
 	struct page *page;
 	void *ptr;
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -62,7 +62,7 @@ u16 hfs_brec_keylen(struct hfs_bnode *no
 	return retval;
 }
 
-int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
+int hfs_brec_insert(struct hfs_find_data *fd, void *entry, u32 entry_len)
 {
 	struct hfs_btree *tree;
 	struct hfs_bnode *node, *new_node;
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -259,7 +259,7 @@ static struct hfs_bnode *hfs_bmap_new_bm
 }
 
 /* Make sure @tree has enough space for the @rsvd_nodes */
-int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
+int hfs_bmap_reserve(struct hfs_btree *tree, u32 rsvd_nodes)
 {
 	struct inode *inode = tree->inode;
 	u32 count;
--- a/fs/hfs/btree.h
+++ b/fs/hfs/btree.h
@@ -86,48 +86,49 @@ struct hfs_find_data {
 
 
 /* btree.c */
-extern struct hfs_btree *hfs_btree_open(struct super_block *, u32, btree_keycmp);
-extern void hfs_btree_close(struct hfs_btree *);
-extern void hfs_btree_write(struct hfs_btree *);
-extern int hfs_bmap_reserve(struct hfs_btree *, int);
-extern struct hfs_bnode * hfs_bmap_alloc(struct hfs_btree *);
+extern struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id,
+					btree_keycmp keycmp);
+extern void hfs_btree_close(struct hfs_btree *tree);
+extern void hfs_btree_write(struct hfs_btree *tree);
+extern int hfs_bmap_reserve(struct hfs_btree *tree, u32 rsvd_nodes);
+extern struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree);
 extern void hfs_bmap_free(struct hfs_bnode *node);
 
 /* bnode.c */
-extern void hfs_bnode_read(struct hfs_bnode *, void *, int, int);
-extern u16 hfs_bnode_read_u16(struct hfs_bnode *, int);
-extern u8 hfs_bnode_read_u8(struct hfs_bnode *, int);
-extern void hfs_bnode_read_key(struct hfs_bnode *, void *, int);
-extern void hfs_bnode_write(struct hfs_bnode *, void *, int, int);
-extern void hfs_bnode_write_u16(struct hfs_bnode *, int, u16);
-extern void hfs_bnode_write_u8(struct hfs_bnode *, int, u8);
-extern void hfs_bnode_clear(struct hfs_bnode *, int, int);
-extern void hfs_bnode_copy(struct hfs_bnode *, int,
-			   struct hfs_bnode *, int, int);
-extern void hfs_bnode_move(struct hfs_bnode *, int, int, int);
-extern void hfs_bnode_dump(struct hfs_bnode *);
-extern void hfs_bnode_unlink(struct hfs_bnode *);
-extern struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *, u32);
-extern struct hfs_bnode *hfs_bnode_find(struct hfs_btree *, u32);
-extern void hfs_bnode_unhash(struct hfs_bnode *);
-extern void hfs_bnode_free(struct hfs_bnode *);
-extern struct hfs_bnode *hfs_bnode_create(struct hfs_btree *, u32);
-extern void hfs_bnode_get(struct hfs_bnode *);
-extern void hfs_bnode_put(struct hfs_bnode *);
+extern void hfs_bnode_read(struct hfs_bnode *node, void *buf, u32 off, u32 len);
+extern u16 hfs_bnode_read_u16(struct hfs_bnode *node, u32 off);
+extern u8 hfs_bnode_read_u8(struct hfs_bnode *node, u32 off);
+extern void hfs_bnode_read_key(struct hfs_bnode *node, void *key, u32 off);
+extern void hfs_bnode_write(struct hfs_bnode *node, void *buf, u32 off, u32 len);
+extern void hfs_bnode_write_u16(struct hfs_bnode *node, u32 off, u16 data);
+extern void hfs_bnode_write_u8(struct hfs_bnode *node, u32 off, u8 data);
+extern void hfs_bnode_clear(struct hfs_bnode *node, u32 off, u32 len);
+extern void hfs_bnode_copy(struct hfs_bnode *dst_node, u32 dst,
+			   struct hfs_bnode *src_node, u32 src, u32 len);
+extern void hfs_bnode_move(struct hfs_bnode *node, u32 dst, u32 src, u32 len);
+extern void hfs_bnode_dump(struct hfs_bnode *node);
+extern void hfs_bnode_unlink(struct hfs_bnode *node);
+extern struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid);
+extern struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num);
+extern void hfs_bnode_unhash(struct hfs_bnode *node);
+extern void hfs_bnode_free(struct hfs_bnode *node);
+extern struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num);
+extern void hfs_bnode_get(struct hfs_bnode *node);
+extern void hfs_bnode_put(struct hfs_bnode *node);
 
 /* brec.c */
-extern u16 hfs_brec_lenoff(struct hfs_bnode *, u16, u16 *);
-extern u16 hfs_brec_keylen(struct hfs_bnode *, u16);
-extern int hfs_brec_insert(struct hfs_find_data *, void *, int);
-extern int hfs_brec_remove(struct hfs_find_data *);
+extern u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off);
+extern u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec);
+extern int hfs_brec_insert(struct hfs_find_data *fd, void *entry, u32 entry_len);
+extern int hfs_brec_remove(struct hfs_find_data *fd);
 
 /* bfind.c */
-extern int hfs_find_init(struct hfs_btree *, struct hfs_find_data *);
-extern void hfs_find_exit(struct hfs_find_data *);
-extern int __hfs_brec_find(struct hfs_bnode *, struct hfs_find_data *);
-extern int hfs_brec_find(struct hfs_find_data *);
-extern int hfs_brec_read(struct hfs_find_data *, void *, int);
-extern int hfs_brec_goto(struct hfs_find_data *, int);
+extern int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd);
+extern void hfs_find_exit(struct hfs_find_data *fd);
+extern int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd);
+extern int hfs_brec_find(struct hfs_find_data *fd);
+extern int hfs_brec_read(struct hfs_find_data *fd, void *rec, u32 rec_len);
+extern int hfs_brec_goto(struct hfs_find_data *fd, int cnt);
 
 
 struct hfs_bnode_desc {
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -171,74 +171,90 @@ struct hfs_sb_info {
 #define HFS_FLG_ALT_MDB_DIRTY	2
 
 /* bitmap.c */
-extern u32 hfs_vbm_search_free(struct super_block *, u32, u32 *);
-extern int hfs_clear_vbm_bits(struct super_block *, u16, u16);
+extern u32 hfs_vbm_search_free(struct super_block *sb, u32 goal, u32 *num_bits);
+extern int hfs_clear_vbm_bits(struct super_block *sb, u16 start, u16 count);
 
 /* catalog.c */
-extern int hfs_cat_keycmp(const btree_key *, const btree_key *);
+extern int hfs_cat_keycmp(const btree_key *key1, const btree_key *key2);
 struct hfs_find_data;
-extern int hfs_cat_find_brec(struct super_block *, u32, struct hfs_find_data *);
-extern int hfs_cat_create(u32, struct inode *, const struct qstr *, struct inode *);
-extern int hfs_cat_delete(u32, struct inode *, const struct qstr *);
-extern int hfs_cat_move(u32, struct inode *, const struct qstr *,
-			struct inode *, const struct qstr *);
-extern void hfs_cat_build_key(struct super_block *, btree_key *, u32, const struct qstr *);
+extern int hfs_cat_find_brec(struct super_block *sb, u32 cnid,
+			     struct hfs_find_data *fd);
+extern int hfs_cat_create(u32 cnid, struct inode *dir,
+			  const struct qstr *str, struct inode *inode);
+extern int hfs_cat_delete(u32 cnid, struct inode *dir, const struct qstr *str);
+extern int hfs_cat_move(u32 cnid, struct inode *src_dir,
+			const struct qstr *src_name,
+			struct inode *dst_dir,
+			const struct qstr *dst_name);
+extern void hfs_cat_build_key(struct super_block *sb, btree_key *key,
+			      u32 parent, const struct qstr *name);
 
 /* dir.c */
 extern const struct file_operations hfs_dir_operations;
 extern const struct inode_operations hfs_dir_inode_operations;
 
 /* extent.c */
-extern int hfs_ext_keycmp(const btree_key *, const btree_key *);
+extern int hfs_ext_keycmp(const btree_key *key1, const btree_key *key2);
 extern u16 hfs_ext_find_block(struct hfs_extent *ext, u16 off);
-extern int hfs_free_fork(struct super_block *, struct hfs_cat_file *, int);
-extern int hfs_ext_write_extent(struct inode *);
-extern int hfs_extend_file(struct inode *);
-extern void hfs_file_truncate(struct inode *);
+extern int hfs_free_fork(struct super_block *sb,
+			 struct hfs_cat_file *file, int type);
+extern int hfs_ext_write_extent(struct inode *inode);
+extern int hfs_extend_file(struct inode *inode);
+extern void hfs_file_truncate(struct inode *inode);
 
-extern int hfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
+extern int hfs_get_block(struct inode *inode, sector_t block,
+			 struct buffer_head *bh_result, int create);
 
 /* inode.c */
 extern const struct address_space_operations hfs_aops;
 extern const struct address_space_operations hfs_btree_aops;
 
 int hfs_write_begin(struct file *file, struct address_space *mapping,
-		loff_t pos, unsigned len, struct folio **foliop, void **fsdata);
-extern struct inode *hfs_new_inode(struct inode *, const struct qstr *, umode_t);
-extern void hfs_inode_write_fork(struct inode *, struct hfs_extent *, __be32 *, __be32 *);
-extern int hfs_write_inode(struct inode *, struct writeback_control *);
-extern int hfs_inode_setattr(struct mnt_idmap *, struct dentry *,
-			     struct iattr *);
+		    loff_t pos, unsigned int len, struct folio **foliop,
+		    void **fsdata);
+extern struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name,
+				   umode_t mode);
+extern void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
+				 __be32 *log_size, __be32 *phys_size);
+extern int hfs_write_inode(struct inode *inode, struct writeback_control *wbc);
+extern int hfs_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+			     struct iattr *attr);
 extern void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
-			__be32 log_size, __be32 phys_size, u32 clump_size);
-extern struct inode *hfs_iget(struct super_block *, struct hfs_cat_key *, hfs_cat_rec *);
-extern void hfs_evict_inode(struct inode *);
-extern void hfs_delete_inode(struct inode *);
+				__be32 __log_size, __be32 phys_size,
+				u32 clump_size);
+extern struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key,
+				hfs_cat_rec *rec);
+extern void hfs_evict_inode(struct inode *inode);
+extern void hfs_delete_inode(struct inode *inode);
 
 /* attr.c */
 extern const struct xattr_handler * const hfs_xattr_handlers[];
 
 /* mdb.c */
-extern int hfs_mdb_get(struct super_block *);
-extern void hfs_mdb_commit(struct super_block *);
-extern void hfs_mdb_close(struct super_block *);
-extern void hfs_mdb_put(struct super_block *);
+extern int hfs_mdb_get(struct super_block *sb);
+extern void hfs_mdb_commit(struct super_block *sb);
+extern void hfs_mdb_close(struct super_block *sb);
+extern void hfs_mdb_put(struct super_block *sb);
 
 /* part_tbl.c */
-extern int hfs_part_find(struct super_block *, sector_t *, sector_t *);
+extern int hfs_part_find(struct super_block *sb,
+			 sector_t *part_start, sector_t *part_size);
 
 /* string.c */
 extern const struct dentry_operations hfs_dentry_operations;
 
-extern int hfs_hash_dentry(const struct dentry *, struct qstr *);
-extern int hfs_strcmp(const unsigned char *, unsigned int,
-		      const unsigned char *, unsigned int);
+extern int hfs_hash_dentry(const struct dentry *dentry, struct qstr *this);
+extern int hfs_strcmp(const unsigned char *s1, unsigned int len1,
+		      const unsigned char *s2, unsigned int len2);
 extern int hfs_compare_dentry(const struct dentry *dentry,
-		unsigned int len, const char *str, const struct qstr *name);
+				unsigned int len, const char *str,
+				const struct qstr *name);
 
 /* trans.c */
-extern void hfs_asc2mac(struct super_block *, struct hfs_name *, const struct qstr *);
-extern int hfs_mac2asc(struct super_block *, char *, const struct hfs_name *);
+extern void hfs_asc2mac(struct super_block *sb,
+			struct hfs_name *out, const struct qstr *in);
+extern int hfs_mac2asc(struct super_block *sb,
+			char *out, const struct hfs_name *in);
 
 /* super.c */
 extern void hfs_mark_mdb_dirty(struct super_block *sb);
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -45,7 +45,8 @@ static void hfs_write_failed(struct addr
 }
 
 int hfs_write_begin(struct file *file, struct address_space *mapping,
-		loff_t pos, unsigned len, struct folio **foliop, void **fsdata)
+		    loff_t pos, unsigned int len, struct folio **foliop,
+		    void **fsdata)
 {
 	int ret;
 
--- a/fs/hfsplus/bfind.c
+++ b/fs/hfsplus/bfind.c
@@ -210,7 +210,7 @@ release:
 	return res;
 }
 
-int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
+int hfs_brec_read(struct hfs_find_data *fd, void *rec, u32 rec_len)
 {
 	int res;
 
--- a/fs/hfsplus/bnode.c
+++ b/fs/hfsplus/bnode.c
@@ -20,10 +20,10 @@
 
 
 /* Copy a specified range of bytes from the raw data of a node */
-void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
+void hfs_bnode_read(struct hfs_bnode *node, void *buf, u32 off, u32 len)
 {
 	struct page **pagep;
-	int l;
+	u32 l;
 
 	memset(buf, 0, len);
 
@@ -33,7 +33,7 @@ void hfs_bnode_read(struct hfs_bnode *no
 	if (len == 0) {
 		pr_err("requested zero length: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, len %d\n",
+		       "node_size %u, offset %u, len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len);
 		return;
@@ -45,17 +45,17 @@ void hfs_bnode_read(struct hfs_bnode *no
 	pagep = node->page + (off >> PAGE_SHIFT);
 	off &= ~PAGE_MASK;
 
-	l = min_t(int, len, PAGE_SIZE - off);
+	l = min_t(u32, len, PAGE_SIZE - off);
 	memcpy_from_page(buf, *pagep, off, l);
 
 	while ((len -= l) != 0) {
 		buf += l;
-		l = min_t(int, len, PAGE_SIZE);
+		l = min_t(u32, len, PAGE_SIZE);
 		memcpy_from_page(buf, *++pagep, 0, l);
 	}
 }
 
-u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
+u16 hfs_bnode_read_u16(struct hfs_bnode *node, u32 off)
 {
 	__be16 data;
 	/* TODO: optimize later... */
@@ -63,7 +63,7 @@ u16 hfs_bnode_read_u16(struct hfs_bnode
 	return be16_to_cpu(data);
 }
 
-u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
+u8 hfs_bnode_read_u8(struct hfs_bnode *node, u32 off)
 {
 	u8 data;
 	/* TODO: optimize later... */
@@ -71,10 +71,10 @@ u8 hfs_bnode_read_u8(struct hfs_bnode *n
 	return data;
 }
 
-void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
+void hfs_bnode_read_key(struct hfs_bnode *node, void *key, u32 off)
 {
 	struct hfs_btree *tree;
-	int key_len;
+	u32 key_len;
 
 	tree = node->tree;
 	if (node->type == HFS_NODE_LEAF ||
@@ -86,17 +86,17 @@ void hfs_bnode_read_key(struct hfs_bnode
 
 	if (key_len > sizeof(hfsplus_btree_key) || key_len < 1) {
 		memset(key, 0, sizeof(hfsplus_btree_key));
-		pr_err("hfsplus: Invalid key length: %d\n", key_len);
+		pr_err("hfsplus: Invalid key length: %u\n", key_len);
 		return;
 	}
 
 	hfs_bnode_read(node, key, off, key_len);
 }
 
-void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
+void hfs_bnode_write(struct hfs_bnode *node, void *buf, u32 off, u32 len)
 {
 	struct page **pagep;
-	int l;
+	u32 l;
 
 	if (!is_bnode_offset_valid(node, off))
 		return;
@@ -104,7 +104,7 @@ void hfs_bnode_write(struct hfs_bnode *n
 	if (len == 0) {
 		pr_err("requested zero length: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, len %d\n",
+		       "node_size %u, offset %u, len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len);
 		return;
@@ -116,29 +116,29 @@ void hfs_bnode_write(struct hfs_bnode *n
 	pagep = node->page + (off >> PAGE_SHIFT);
 	off &= ~PAGE_MASK;
 
-	l = min_t(int, len, PAGE_SIZE - off);
+	l = min_t(u32, len, PAGE_SIZE - off);
 	memcpy_to_page(*pagep, off, buf, l);
 	set_page_dirty(*pagep);
 
 	while ((len -= l) != 0) {
 		buf += l;
-		l = min_t(int, len, PAGE_SIZE);
+		l = min_t(u32, len, PAGE_SIZE);
 		memcpy_to_page(*++pagep, 0, buf, l);
 		set_page_dirty(*pagep);
 	}
 }
 
-void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
+void hfs_bnode_write_u16(struct hfs_bnode *node, u32 off, u16 data)
 {
 	__be16 v = cpu_to_be16(data);
 	/* TODO: optimize later... */
 	hfs_bnode_write(node, &v, off, 2);
 }
 
-void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
+void hfs_bnode_clear(struct hfs_bnode *node, u32 off, u32 len)
 {
 	struct page **pagep;
-	int l;
+	u32 l;
 
 	if (!is_bnode_offset_valid(node, off))
 		return;
@@ -146,7 +146,7 @@ void hfs_bnode_clear(struct hfs_bnode *n
 	if (len == 0) {
 		pr_err("requested zero length: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, len %d\n",
+		       "node_size %u, offset %u, len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len);
 		return;
@@ -158,22 +158,22 @@ void hfs_bnode_clear(struct hfs_bnode *n
 	pagep = node->page + (off >> PAGE_SHIFT);
 	off &= ~PAGE_MASK;
 
-	l = min_t(int, len, PAGE_SIZE - off);
+	l = min_t(u32, len, PAGE_SIZE - off);
 	memzero_page(*pagep, off, l);
 	set_page_dirty(*pagep);
 
 	while ((len -= l) != 0) {
-		l = min_t(int, len, PAGE_SIZE);
+		l = min_t(u32, len, PAGE_SIZE);
 		memzero_page(*++pagep, 0, l);
 		set_page_dirty(*pagep);
 	}
 }
 
-void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
-		    struct hfs_bnode *src_node, int src, int len)
+void hfs_bnode_copy(struct hfs_bnode *dst_node, u32 dst,
+		    struct hfs_bnode *src_node, u32 src, u32 len)
 {
 	struct page **src_page, **dst_page;
-	int l;
+	u32 l;
 
 	hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
 	if (!len)
@@ -190,12 +190,12 @@ void hfs_bnode_copy(struct hfs_bnode *ds
 	dst &= ~PAGE_MASK;
 
 	if (src == dst) {
-		l = min_t(int, len, PAGE_SIZE - src);
+		l = min_t(u32, len, PAGE_SIZE - src);
 		memcpy_page(*dst_page, src, *src_page, src, l);
 		set_page_dirty(*dst_page);
 
 		while ((len -= l) != 0) {
-			l = min_t(int, len, PAGE_SIZE);
+			l = min_t(u32, len, PAGE_SIZE);
 			memcpy_page(*++dst_page, 0, *++src_page, 0, l);
 			set_page_dirty(*dst_page);
 		}
@@ -227,11 +227,11 @@ void hfs_bnode_copy(struct hfs_bnode *ds
 	}
 }
 
-void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
+void hfs_bnode_move(struct hfs_bnode *node, u32 dst, u32 src, u32 len)
 {
 	struct page **src_page, **dst_page;
 	void *src_ptr, *dst_ptr;
-	int l;
+	u32 l;
 
 	hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
 	if (!len)
@@ -301,7 +301,7 @@ void hfs_bnode_move(struct hfs_bnode *no
 		dst &= ~PAGE_MASK;
 
 		if (src == dst) {
-			l = min_t(int, len, PAGE_SIZE - src);
+			l = min_t(u32, len, PAGE_SIZE - src);
 
 			dst_ptr = kmap_local_page(*dst_page) + src;
 			src_ptr = kmap_local_page(*src_page) + src;
@@ -311,7 +311,7 @@ void hfs_bnode_move(struct hfs_bnode *no
 			kunmap_local(dst_ptr);
 
 			while ((len -= l) != 0) {
-				l = min_t(int, len, PAGE_SIZE);
+				l = min_t(u32, len, PAGE_SIZE);
 				dst_ptr = kmap_local_page(*++dst_page);
 				src_ptr = kmap_local_page(*++src_page);
 				memmove(dst_ptr, src_ptr, l);
--- a/fs/hfsplus/brec.c
+++ b/fs/hfsplus/brec.c
@@ -60,7 +60,7 @@ u16 hfs_brec_keylen(struct hfs_bnode *no
 	return retval;
 }
 
-int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
+int hfs_brec_insert(struct hfs_find_data *fd, void *entry, u32 entry_len)
 {
 	struct hfs_btree *tree;
 	struct hfs_bnode *node, *new_node;
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -344,7 +344,7 @@ static struct hfs_bnode *hfs_bmap_new_bm
 }
 
 /* Make sure @tree has enough space for the @rsvd_nodes */
-int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
+int hfs_bmap_reserve(struct hfs_btree *tree, u32 rsvd_nodes)
 {
 	struct inode *inode = tree->inode;
 	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -389,21 +389,21 @@ u32 hfsplus_calc_btree_clump_size(u32 bl
 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id);
 void hfs_btree_close(struct hfs_btree *tree);
 int hfs_btree_write(struct hfs_btree *tree);
-int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes);
+int hfs_bmap_reserve(struct hfs_btree *tree, u32 rsvd_nodes);
 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree);
 void hfs_bmap_free(struct hfs_bnode *node);
 
 /* bnode.c */
-void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len);
-u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off);
-u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off);
-void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off);
-void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len);
-void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data);
-void hfs_bnode_clear(struct hfs_bnode *node, int off, int len);
-void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
-		    struct hfs_bnode *src_node, int src, int len);
-void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len);
+void hfs_bnode_read(struct hfs_bnode *node, void *buf, u32 off, u32 len);
+u16 hfs_bnode_read_u16(struct hfs_bnode *node, u32 off);
+u8 hfs_bnode_read_u8(struct hfs_bnode *node, u32 off);
+void hfs_bnode_read_key(struct hfs_bnode *node, void *key, u32 off);
+void hfs_bnode_write(struct hfs_bnode *node, void *buf, u32 off, u32 len);
+void hfs_bnode_write_u16(struct hfs_bnode *node, u32 off, u16 data);
+void hfs_bnode_clear(struct hfs_bnode *node, u32 off, u32 len);
+void hfs_bnode_copy(struct hfs_bnode *dst_node, u32 dst,
+		    struct hfs_bnode *src_node, u32 src, u32 len);
+void hfs_bnode_move(struct hfs_bnode *node, u32 dst, u32 src, u32 len);
 void hfs_bnode_dump(struct hfs_bnode *node);
 void hfs_bnode_unlink(struct hfs_bnode *node);
 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid);
@@ -418,7 +418,7 @@ bool hfs_bnode_need_zeroout(struct hfs_b
 /* brec.c */
 u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off);
 u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec);
-int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len);
+int hfs_brec_insert(struct hfs_find_data *fd, void *entry, u32 entry_len);
 int hfs_brec_remove(struct hfs_find_data *fd);
 
 /* bfind.c */
@@ -431,7 +431,7 @@ int hfs_find_rec_by_key(struct hfs_bnode
 int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd,
 		    search_strategy_t rec_found);
 int hfs_brec_find(struct hfs_find_data *fd, search_strategy_t do_key_compare);
-int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len);
+int hfs_brec_read(struct hfs_find_data *fd, void *rec, u32 rec_len);
 int hfs_brec_goto(struct hfs_find_data *fd, int cnt);
 
 /* catalog.c */
@@ -589,14 +589,14 @@ hfsplus_btree_lock_class(struct hfs_btre
 }
 
 static inline
-bool is_bnode_offset_valid(struct hfs_bnode *node, int off)
+bool is_bnode_offset_valid(struct hfs_bnode *node, u32 off)
 {
 	bool is_valid = off < node->tree->node_size;
 
 	if (!is_valid) {
 		pr_err("requested invalid offset: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d\n",
+		       "node_size %u, offset %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off);
 	}
@@ -605,7 +605,7 @@ bool is_bnode_offset_valid(struct hfs_bn
 }
 
 static inline
-int check_and_correct_requested_length(struct hfs_bnode *node, int off, int len)
+u32 check_and_correct_requested_length(struct hfs_bnode *node, u32 off, u32 len)
 {
 	unsigned int node_size;
 
@@ -615,12 +615,12 @@ int check_and_correct_requested_length(s
 	node_size = node->tree->node_size;
 
 	if ((off + len) > node_size) {
-		int new_len = (int)node_size - off;
+		u32 new_len = node_size - off;
 
 		pr_err("requested length has been corrected: "
 		       "NODE: id %u, type %#x, height %u, "
-		       "node_size %u, offset %d, "
-		       "requested_len %d, corrected_len %d\n",
+		       "node_size %u, offset %u, "
+		       "requested_len %u, corrected_len %u\n",
 		       node->this, node->type, node->height,
 		       node->tree->node_size, off, len, new_len);
 

[PATCH 6.12 1257/1276] afs: Fix afs_atcell_get_link() to check if ws_cell is unset first

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

commit 0307d16f3610eb29ad0b7529846de7d62fed60ca upstream.

Fix afs_atcell_get_link() to check if the workstation cell is unset before
doing the RCU pathwalk bit where we dereference that.

Fixes: 823869e1e616 ("afs: Fix afs_atcell_get_link() to handle RCU pathwalk")
Reported-by: syzbot+76a6f18e3af82e84f264@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/2481796.1742296819@warthog.procyon.org.uk
Tested-by: syzbot+76a6f18e3af82e84f264@syzkaller.appspotmail.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/afs/dynroot.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -209,6 +209,9 @@ static const char *afs_atcell_get_link(s
 	const char *name;
 	bool dotted = vnode->fid.vnode == 3;
 
+	if (!rcu_access_pointer(net->ws_cell))
+		return ERR_PTR(-ENOENT);
+
 	if (!dentry) {
 		/* We're in RCU-pathwalk. */
 		cell = rcu_dereference(net->ws_cell);
@@ -220,9 +223,6 @@ static const char *afs_atcell_get_link(s
 		return name;
 	}
 
-	if (!rcu_access_pointer(net->ws_cell))
-		return ERR_PTR(-ENOENT);
-
 	down_read(&net->cells_lock);
 
 	cell = rcu_dereference_protected(net->ws_cell, lockdep_is_held(&net->cells_lock));

[PATCH 6.12 1258/1276] afs: Fix afs_dynroot_readdir() to not use the RCU read lock

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

commit a64e4d48a0b77e4ada19ac26ca3a08cd492f6362 upstream.

afs_dynroot_readdir() uses the RCU read lock to walk the cell list whilst
emitting cell automount entries - but dir_emit() may write to a userspace
buffer, thereby causing a fault to occur and waits to happen.

Fix afs_dynroot_readdir() to get a shared lock on net->cells_lock instead.

This can be triggered by enabling lockdep, preconfiguring a number of
cells, doing "mount -t afs none /afs -o dyn" (or using the kafs-client
package with afs.mount systemd unit enabled) and then doing "ls /afs".

Fixes: 1d0b929fc070 ("afs: Change dynroot to create contents on demand")
Reported-by: syzbot+3b6c5c6a1d0119b687a1@syzkaller.appspotmail.com
Reported-by: syzbot+8245611446194a52150d@syzkaller.appspotmail.com
Reported-by: syzbot+1aa62e6852a6ad1c7944@syzkaller.appspotmail.com
Reported-by: syzbot+54e6c2176ba76c56217e@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/1638014.1744145189@warthog.procyon.org.uk
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/afs/dynroot.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -347,9 +347,9 @@ static int afs_dynroot_readdir(struct fi
 	}
 
 	if ((unsigned long long)ctx->pos <= AFS_MAX_DYNROOT_CELL_INO) {
-		rcu_read_lock();
+		down_read(&net->cells_lock);
 		ret = afs_dynroot_readdir_cells(net, ctx);
-		rcu_read_unlock();
+		up_read(&net->cells_lock);
 	}
 	return ret;
 }