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, 2 insertions, 0 deletions

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 3c13981f48e2..49d716036ea7 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -56,6 +56,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb)
         fi->i_time = 0;
         fi->nodeid = 0;
         fi->nlookup = 0;
+        INIT_LIST_HEAD(&fi->write_files);
         fi->forget_req = fuse_request_alloc();
         if (!fi->forget_req) {
                 kmem_cache_free(fuse_inode_cachep, inode);
@@ -68,6 +69,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb)
 static void fuse_destroy_inode(struct inode *inode)
 {
         struct fuse_inode *fi = get_fuse_inode(inode);
+        BUG_ON(!list_empty(&fi->write_files));
         if (fi->forget_req)
                 fuse_request_free(fi->forget_req);
         kmem_cache_free(fuse_inode_cachep, inode);