1 files changed, 49 insertions, 54 deletions

diff --git a/fs/fsopen.c b/fs/fsopen.c
index 6593ae518115..f645c99204eb 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -18,50 +18,56 @@
 #include "internal.h"
 #include "mount.h"
 
+static inline const char *fetch_message_locked(struct fc_log *log, size_t len,
+					       bool *need_free)
+{
+	const char *p;
+	int index;
+
+	if (unlikely(log->head == log->tail))
+		return ERR_PTR(-ENODATA);
+
+	index = log->tail & (ARRAY_SIZE(log->buffer) - 1);
+	p = log->buffer[index];
+	if (unlikely(strlen(p) > len))
+		return ERR_PTR(-EMSGSIZE);
+
+	log->buffer[index] = NULL;
+	*need_free = log->need_free & (1 << index);
+	log->need_free &= ~(1 << index);
+	log->tail++;
+
+	return p;
+}
+
 /*
  * Allow the user to read back any error, warning or informational messages.
+ * Only one message is returned for each read(2) call.
  */
 static ssize_t fscontext_read(struct file *file,
 			      char __user *_buf, size_t len, loff_t *pos)
 {
 	struct fs_context *fc = file->private_data;
-	struct fc_log *log = fc->log.log;
-	unsigned int logsize = ARRAY_SIZE(log->buffer);
-	ssize_t ret;
-	char *p;
+	ssize_t err;
+	const char *p __free(kfree) = NULL, *message;
 	bool need_free;
-	int index, n;
-
-	ret = mutex_lock_interruptible(&fc->uapi_mutex);
-	if (ret < 0)
-		return ret;
+	int n;
 
-	if (log->head == log->tail) {
-		mutex_unlock(&fc->uapi_mutex);
-		return -ENODATA;
-	}
-
-	index = log->tail & (logsize - 1);
-	p = log->buffer[index];
-	need_free = log->need_free & (1 << index);
-	log->buffer[index] = NULL;
-	log->need_free &= ~(1 << index);
-	log->tail++;
+	err = mutex_lock_interruptible(&fc->uapi_mutex);
+	if (err < 0)
+		return err;
+	message = fetch_message_locked(fc->log.log, len, &need_free);
 	mutex_unlock(&fc->uapi_mutex);
+	if (IS_ERR(message))
+		return PTR_ERR(message);
 
-	ret = -EMSGSIZE;
-	n = strlen(p);
-	if (n > len)
-		goto err_free;
-	ret = -EFAULT;
-	if (copy_to_user(_buf, p, n) != 0)
-		goto err_free;
-	ret = n;
-
-err_free:
 	if (need_free)
-		kfree(p);
-	return ret;
+		p = message;
+
+	n = strlen(message);
+	if (copy_to_user(_buf, message, n))
+		return -EFAULT;
+	return n;
 }
 
 static int fscontext_release(struct inode *inode, struct file *file)
@@ -78,7 +84,6 @@ static int fscontext_release(struct inode *inode, struct file *file)
 const struct file_operations fscontext_fops = {
 	.read		= fscontext_read,
 	.release	= fscontext_release,
-	.llseek		= no_llseek,
 };
 
 /*
@@ -220,10 +225,6 @@ static int vfs_cmd_create(struct fs_context *fc, bool exclusive)
 	if (!mount_capable(fc))
 		return -EPERM;
 
-	/* require the new mount api */
-	if (exclusive && fc->ops == &legacy_fs_context_ops)
-		return -EOPNOTSUPP;
-
 	fc->phase = FS_CONTEXT_CREATING;
 	fc->exclusive = exclusive;
 
@@ -354,7 +355,6 @@ SYSCALL_DEFINE5(fsconfig,
 		int, aux)
 {
 	struct fs_context *fc;
-	struct fd f;
 	int ret;
 	int lookup_flags = 0;
 
@@ -397,31 +397,28 @@ SYSCALL_DEFINE5(fsconfig,
 		return -EOPNOTSUPP;
 	}
 
-	f = fdget(fd);
-	if (!f.file)
+	CLASS(fd, f)(fd);
+	if (fd_empty(f))
 		return -EBADF;
-	ret = -EINVAL;
-	if (f.file->f_op != &fscontext_fops)
-		goto out_f;
+	if (fd_file(f)->f_op != &fscontext_fops)
+		return -EINVAL;
 
-	fc = f.file->private_data;
+	fc = fd_file(f)->private_data;
 	if (fc->ops == &legacy_fs_context_ops) {
 		switch (cmd) {
 		case FSCONFIG_SET_BINARY:
 		case FSCONFIG_SET_PATH:
 		case FSCONFIG_SET_PATH_EMPTY:
 		case FSCONFIG_SET_FD:
-			ret = -EOPNOTSUPP;
-			goto out_f;
+		case FSCONFIG_CMD_CREATE_EXCL:
+			return -EOPNOTSUPP;
 		}
 	}
 
 	if (_key) {
 		param.key = strndup_user(_key, 256);
-		if (IS_ERR(param.key)) {
-			ret = PTR_ERR(param.key);
-			goto out_f;
-		}
+		if (IS_ERR(param.key))
+			return PTR_ERR(param.key);
 	}
 
 	switch (cmd) {
@@ -451,7 +448,7 @@ SYSCALL_DEFINE5(fsconfig,
 		fallthrough;
 	case FSCONFIG_SET_PATH:
 		param.type = fs_value_is_filename;
-		param.name = getname_flags(_value, lookup_flags, NULL);
+		param.name = getname_flags(_value, lookup_flags);
 		if (IS_ERR(param.name)) {
 			ret = PTR_ERR(param.name);
 			goto out_key;
@@ -462,7 +459,7 @@ SYSCALL_DEFINE5(fsconfig,
 	case FSCONFIG_SET_FD:
 		param.type = fs_value_is_file;
 		ret = -EBADF;
-		param.file = fget(aux);
+		param.file = fget_raw(aux);
 		if (!param.file)
 			goto out_key;
 		param.dirfd = aux;
@@ -500,7 +497,5 @@ SYSCALL_DEFINE5(fsconfig,
 	}
 out_key:
 	kfree(param.key);
-out_f:
-	fdput(f);
 	return ret;
 }