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Commit 69886e67 authored by Richard Weinberger's avatar Richard Weinberger
Browse files

hostfs: hostfs_file_open: Switch to data locking model 



Instead of serializing hostfs_file_open() we can use
a per inode mutex to protect ->mode.

Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent bc465aa9

fs/hostfs/hostfs_kern.c

+7 −6
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ struct hostfs_inode_info { 
	int fd;

	fmode_t mode;

	struct inode vfs_inode;

	struct mutex open_mutex;

};



static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
@@ -225,6 +226,7 @@ static struct inode *hostfs_alloc_inode(struct super_block *sb) 
	hi->fd = -1;

	hi->mode = 0;

	inode_init_once(&hi->vfs_inode);

	mutex_init(&hi->open_mutex);

	return &hi->vfs_inode;

}
@@ -295,7 +297,6 @@ static int hostfs_readdir(struct file *file, struct dir_context *ctx) 


static int hostfs_file_open(struct inode *ino, struct file *file)

{

	static DEFINE_MUTEX(open_mutex);

	char *name;

	fmode_t mode = 0;

	int err;
@@ -324,15 +325,15 @@ static int hostfs_file_open(struct inode *ino, struct file *file) 
	if (fd < 0)

		return fd;



	mutex_lock(&open_mutex);

	mutex_lock(&HOSTFS_I(ino)->open_mutex);

	/* somebody else had handled it first? */

	if ((mode & HOSTFS_I(ino)->mode) == mode) {

		mutex_unlock(&open_mutex);

		mutex_unlock(&HOSTFS_I(ino)->open_mutex);

		return 0;

	}

	if ((mode | HOSTFS_I(ino)->mode) != mode) {

		mode |= HOSTFS_I(ino)->mode;

		mutex_unlock(&open_mutex);

		mutex_unlock(&HOSTFS_I(ino)->open_mutex);

		close_file(&fd);

		goto retry;

	}
@@ -342,12 +343,12 @@ static int hostfs_file_open(struct inode *ino, struct file *file) 
		err = replace_file(fd, HOSTFS_I(ino)->fd);

		close_file(&fd);

		if (err < 0) {

			mutex_unlock(&open_mutex);

			mutex_unlock(&HOSTFS_I(ino)->open_mutex);

			return err;

		}

	}

	HOSTFS_I(ino)->mode = mode;

	mutex_unlock(&open_mutex);

	mutex_unlock(&HOSTFS_I(ino)->open_mutex);



	return 0;

}