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, 6 insertions, 0 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index b24fc9b386f8..5657cca0d0cb 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -70,6 +70,9 @@ struct fuse_inode {
 
         /** Version of last attribute change */
         u64 attr_version;
+
+        /** Files usable in writepage.  Protected by fc->lock */
+        struct list_head write_files;
 };
 
 /** FUSE specific file data */
@@ -82,6 +85,9 @@ struct fuse_file {
 
         /** Refcount */
         atomic_t count;
+
+        /** Entry on inode's write_files list */
+        struct list_head write_entry;
 };
 
 /** One input argument of a request */