fuse: add list of writable files to fuse_inode

Each WRITE request must carry a valid file descriptor.  When a page is written
back from a memory mapping, the file through which the page was dirtied is not
available, so a new mechananism is needed to find a suitable file in
->writepage(s).

A list of fuse_files is added to fuse_inode.  The file is removed from the
list in fuse_release().

This patch is in preparation for writable mmap support.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 471ea70be48d..c4c59c7d0038 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -56,6 +56,7 @@ struct fuse_file *fuse_file_alloc(void)
                         kfree(ff);
                         ff = NULL;
                 }
+                INIT_LIST_HEAD(&ff->write_entry);
                 atomic_set(&ff->count, 0);
         }
         return ff;
@@ -150,12 +151,18 @@ int fuse_release_common(struct inode *inode, struct file *file, int isdir)
 {
         struct fuse_file *ff = file->private_data;
         if (ff) {
+                struct fuse_conn *fc = get_fuse_conn(inode);
+
                 fuse_release_fill(ff, get_node_id(inode), file->f_flags,
                                   isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
 
                 /* Hold vfsmount and dentry until release is finished */
                 ff->reserved_req->vfsmount = mntget(file->f_path.mnt);
                 ff->reserved_req->dentry = dget(file->f_path.dentry);
+
+                spin_lock(&fc->lock);
+                list_del(&ff->write_entry);
+                spin_unlock(&fc->lock);
                 /*
                  * Normally this will send the RELEASE request,
                  * however if some asynchronous READ or WRITE requests