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From:   Christoph Hellwig <hch@lst.de>
To:     torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
        dhowells@redhat.com
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Amir Goldstein <amir73il@gmail.com>
Subject: [PATCH v2] fs: rename S_KERNEL_FILE
Date:   Fri, 28 Jan 2022 08:47:31 +0100
Message-Id: <20220128074731.1623738-1-hch@lst.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

S_KERNEL_FILE is grossly misnamed.  We have plenty of files hold open by
the kernel kernel using filp_open.  This flag OTOH signals the inode as
being a special snowflake that cachefiles holds onto that can't be
unlinked because of ..., erm, pixie dust.  So clearly mark it as such.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
---

Changes since v1:
 - fix commit message typos

 fs/cachefiles/namei.c | 12 ++++++------
 fs/namei.c            |  2 +-
 include/linux/fs.h    |  2 +-
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 9bd692870617c..599dc13a7d9ab 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -20,8 +20,8 @@ static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
 	struct inode *inode = d_backing_inode(dentry);
 	bool can_use = false;
 
-	if (!(inode->i_flags & S_KERNEL_FILE)) {
-		inode->i_flags |= S_KERNEL_FILE;
+	if (!(inode->i_flags & S_CACHEFILE)) {
+		inode->i_flags |= S_CACHEFILE;
 		trace_cachefiles_mark_active(object, inode);
 		can_use = true;
 	} else {
@@ -51,7 +51,7 @@ static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 {
 	struct inode *inode = d_backing_inode(dentry);
 
-	inode->i_flags &= ~S_KERNEL_FILE;
+	inode->i_flags &= ~S_CACHEFILE;
 	trace_cachefiles_mark_inactive(object, inode);
 }
 
@@ -742,7 +742,7 @@ static struct dentry *cachefiles_lookup_for_cull(struct cachefiles_cache *cache,
 		goto lookup_error;
 	if (d_is_negative(victim))
 		goto lookup_put;
-	if (d_inode(victim)->i_flags & S_KERNEL_FILE)
+	if (d_inode(victim)->i_flags & S_CACHEFILE)
 		goto lookup_busy;
 	return victim;
 
@@ -789,11 +789,11 @@ int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 	/* check to see if someone is using this object */
 	inode = d_inode(victim);
 	inode_lock(inode);
-	if (inode->i_flags & S_KERNEL_FILE) {
+	if (inode->i_flags & S_CACHEFILE) {
 		ret = -EBUSY;
 	} else {
 		/* Stop the cache from picking it back up */
-		inode->i_flags |= S_KERNEL_FILE;
+		inode->i_flags |= S_CACHEFILE;
 		ret = 0;
 	}
 	inode_unlock(inode);
diff --git a/fs/namei.c b/fs/namei.c
index d81f04f8d8188..7402277ecc1f5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3959,7 +3959,7 @@ int vfs_rmdir(struct user_namespace *mnt_userns, struct inode *dir,
 
 	error = -EBUSY;
 	if (is_local_mountpoint(dentry) ||
-	    (dentry->d_inode->i_flags & S_KERNEL_FILE))
+	    (dentry->d_inode->i_flags & S_CACHEFILE))
 		goto out;
 
 	error = security_inode_rmdir(dir, dentry);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c8510da6cc6dc..099d7e03d46e6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2173,7 +2173,7 @@ struct super_operations {
 #define S_ENCRYPTED	(1 << 14) /* Encrypted file (using fs/crypto/) */
 #define S_CASEFOLD	(1 << 15) /* Casefolded file */
 #define S_VERITY	(1 << 16) /* Verity file (using fs/verity/) */
-#define S_KERNEL_FILE	(1 << 17) /* File is in use by the kernel (eg. fs/cachefiles) */
+#define S_CACHEFILE	(1 << 17) /* In use as cachefile, can't be unlinked */
 
 /*
  * Note that nosuid etc flags are inode-specific: setting some file-system
-- 
2.30.2