[patch 09/12] fuse: add list of writable files to fuse_inode

Miklos Szeredi
2007-10-02T15:55:46Z

[-- Attachment #1: fuse_write_files.patch --]
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From: Miklos Szeredi <mszeredi@suse.cz>

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>
---

Index: linux/fs/fuse/file.c
===================================================================
--- linux.orig/fs/fuse/file.c 2007-10-01 22:42:26.000000000 +0200
+++ linux/fs/fuse/file.c 2007-10-01 22:42:27.000000000 +0200
@@ -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 *in
{
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
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h 2007-10-01 22:42:24.000000000 +0200
+++ linux/fs/fuse/fuse_i.h 2007-10-01 22:43:15.000000000 +0200
@@ -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 */
Index: linux/fs/fuse/inode.c
===================================================================
--- linux.orig/fs/fuse/inode.c 2007-10-01 22:42:24.000000000 +0200
+++ linux/fs/fuse/inode.c 2007-10-01 22:42:27.000000000 +0200
@@ -56,6 +56,7 @@ static struct inode *fuse_alloc_inode(st
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(st
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);

--