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: Richard Weinberger <richard@nod.at>

1 files changed, 7 insertions, 6 deletions

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index fd62cae0fdcb..104d58d2c78c 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -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 @@ retry:
         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 @@ retry:
                 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;
 }