linux-kernel - [PATCH v2 5/5] fs: Add inode_assert_locked() and inode_assert_locked

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Message-Id: <20231007203543.1377452-6-willy@infradead.org>
Date:   Sat,  7 Oct 2023 21:35:43 +0100
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Chandan Babu R <chandan.babu@...cle.com>,
        "Darrick J . Wong" <djwong@...nel.org>, linux-xfs@...r.kernel.org,
        Mateusz Guzik <mjguzik@...il.com>
Subject: [PATCH v2 5/5] fs: Add inode_assert_locked() and inode_assert_locked_excl()

Use the new rwsem_assert_held functions to implement these new
assertions.  Convert the inode_is_locked() callers in the VFS to
use them.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 fs/attr.c          |  2 +-
 fs/namei.c         |  6 +++---
 include/linux/fs.h | 10 ++++++++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index a8ae5f6d9b16..5e32b0a4f8c2 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -387,7 +387,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
 	struct timespec64 now;
 	unsigned int ia_valid = attr->ia_valid;
 
-	WARN_ON_ONCE(!inode_is_locked(inode));
+	inode_assert_locked_excl(inode);
 
 	error = may_setattr(idmap, inode, ia_valid);
 	if (error)
diff --git a/fs/namei.c b/fs/namei.c
index 567ee547492b..6b595ad4318d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2708,7 +2708,7 @@ struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len
 	struct qstr this;
 	int err;
 
-	WARN_ON_ONCE(!inode_is_locked(base->d_inode));
+	inode_assert_locked(base->d_inode);
 
 	err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this);
 	if (err)
@@ -2735,7 +2735,7 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 	struct qstr this;
 	int err;
 
-	WARN_ON_ONCE(!inode_is_locked(base->d_inode));
+	inode_assert_locked(base->d_inode);
 
 	err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this);
 	if (err)
@@ -2765,7 +2765,7 @@ struct dentry *lookup_one(struct mnt_idmap *idmap, const char *name,
 	struct qstr this;
 	int err;
 
-	WARN_ON_ONCE(!inode_is_locked(base->d_inode));
+	inode_assert_locked(base->d_inode);
 
 	err = lookup_one_common(idmap, name, base, len, &this);
 	if (err)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b528f063e8ff..e01e041c102b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -832,6 +832,16 @@ static inline int inode_is_locked(struct inode *inode)
 	return rwsem_is_locked(&inode->i_rwsem);
 }
 
+static inline void inode_assert_locked(const struct inode *inode)
+{
+	rwsem_assert_held(&inode->i_rwsem);
+}
+
+static inline void inode_assert_locked_excl(const struct inode *inode)
+{
+	rwsem_assert_held_write(&inode->i_rwsem);
+}
+
 static inline void inode_lock_nested(struct inode *inode, unsigned subclass)
 {
 	down_write_nested(&inode->i_rwsem, subclass);
-- 
2.40.1