[PATCH] fuse: no backgrounding on interrupt

Don't put requests into the background when a fatal interrupt occurs while the
request is in userspace.  This removes a major wart from the implementation.

Backgrounding of requests was introduced to allow breaking of deadlocks.
However now the same can be achieved by aborting the filesystem through the
'abort' sysfs attribute.

This is a change in the interface, but should not cause problems, since these
kinds of deadlocks never happen during normal operation.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 30 insertions, 26 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 8d7546e832e..72a74cde6de 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1,6 +1,6 @@
 /*
   FUSE: Filesystem in Userspace
-  Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>
+  Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>
 
   This program can be distributed under the terms of the GNU GPL.
   See the file COPYING.
@@ -79,7 +79,6 @@ static void fuse_lookup_init(struct fuse_req *req, struct inode *dir,
 {
 	req->in.h.opcode = FUSE_LOOKUP;
 	req->in.h.nodeid = get_node_id(dir);
-	req->inode = dir;
 	req->in.numargs = 1;
 	req->in.args[0].size = entry->d_name.len + 1;
 	req->in.args[0].value = entry->d_name.name;
@@ -225,6 +224,20 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 }
 
 /*
+ * Synchronous release for the case when something goes wrong in CREATE_OPEN
+ */
+static void fuse_sync_release(struct fuse_conn *fc, struct fuse_file *ff,
+			      u64 nodeid, int flags)
+{
+	struct fuse_req *req;
+
+	req = fuse_release_fill(ff, nodeid, flags, FUSE_RELEASE);
+	req->force = 1;
+	request_send(fc, req);
+	fuse_put_request(fc, req);
+}
+
+/*
  * Atomic create+open operation
  *
  * If the filesystem doesn't support this, then fall back to separate
@@ -237,6 +250,7 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, int mode,
 	struct inode *inode;
 	struct fuse_conn *fc = get_fuse_conn(dir);
 	struct fuse_req *req;
+	struct fuse_req *forget_req;
 	struct fuse_open_in inarg;
 	struct fuse_open_out outopen;
 	struct fuse_entry_out outentry;
@@ -247,9 +261,14 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, int mode,
 	if (fc->no_create)
 		return -ENOSYS;
 
+	forget_req = fuse_get_req(fc);
+	if (IS_ERR(forget_req))
+		return PTR_ERR(forget_req);
+
 	req = fuse_get_req(fc);
+	err = PTR_ERR(req);
 	if (IS_ERR(req))
-		return PTR_ERR(req);
+		goto out_put_forget_req;
 
 	err = -ENOMEM;
 	ff = fuse_file_alloc();
@@ -262,7 +281,6 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, int mode,
 	inarg.mode = mode;
 	req->in.h.opcode = FUSE_CREATE;
 	req->in.h.nodeid = get_node_id(dir);
-	req->inode = dir;
 	req->in.numargs = 2;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -285,25 +303,23 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, int mode,
 	if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
 		goto out_free_ff;
 
+	fuse_put_request(fc, req);
 	inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
 			  &outentry.attr);
-	err = -ENOMEM;
 	if (!inode) {
 		flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
 		ff->fh = outopen.fh;
-		/* Special release, with inode = NULL, this will
-		   trigger a 'forget' request when the release is
-		   complete */
-		fuse_send_release(fc, ff, outentry.nodeid, NULL, flags, 0);
-		goto out_put_request;
+		fuse_sync_release(fc, ff, outentry.nodeid, flags);
+		fuse_send_forget(fc, forget_req, outentry.nodeid, 1);
+		return -ENOMEM;
 	}
-	fuse_put_request(fc, req);
+	fuse_put_request(fc, forget_req);
 	d_instantiate(entry, inode);
 	fuse_change_timeout(entry, &outentry);
 	file = lookup_instantiate_filp(nd, entry, generic_file_open);
 	if (IS_ERR(file)) {
 		ff->fh = outopen.fh;
-		fuse_send_release(fc, ff, outentry.nodeid, inode, flags, 0);
+		fuse_sync_release(fc, ff, outentry.nodeid, flags);
 		return PTR_ERR(file);
 	}
 	fuse_finish_open(inode, file, ff, &outopen);
@@ -313,6 +329,8 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry, int mode,
 	fuse_file_free(ff);
  out_put_request:
 	fuse_put_request(fc, req);
+ out_put_forget_req:
+	fuse_put_request(fc, forget_req);
 	return err;
 }
 
@@ -328,7 +346,6 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
 	int err;
 
 	req->in.h.nodeid = get_node_id(dir);
-	req->inode = dir;
 	req->out.numargs = 1;
 	req->out.args[0].size = sizeof(outarg);
 	req->out.args[0].value = &outarg;
@@ -448,7 +465,6 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
 
 	req->in.h.opcode = FUSE_UNLINK;
 	req->in.h.nodeid = get_node_id(dir);
-	req->inode = dir;
 	req->in.numargs = 1;
 	req->in.args[0].size = entry->d_name.len + 1;
 	req->in.args[0].value = entry->d_name.name;
@@ -480,7 +496,6 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry)
 
 	req->in.h.opcode = FUSE_RMDIR;
 	req->in.h.nodeid = get_node_id(dir);
-	req->inode = dir;
 	req->in.numargs = 1;
 	req->in.args[0].size = entry->d_name.len + 1;
 	req->in.args[0].value = entry->d_name.name;
@@ -510,8 +525,6 @@ static int fuse_rename(struct inode *olddir, struct dentry *oldent,
 	inarg.newdir = get_node_id(newdir);
 	req->in.h.opcode = FUSE_RENAME;
 	req->in.h.nodeid = get_node_id(olddir);
-	req->inode = olddir;
-	req->inode2 = newdir;
 	req->in.numargs = 3;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -558,7 +571,6 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.oldnodeid = get_node_id(inode);
 	req->in.h.opcode = FUSE_LINK;
-	req->inode2 = inode;
 	req->in.numargs = 2;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -587,7 +599,6 @@ int fuse_do_getattr(struct inode *inode)
 
 	req->in.h.opcode = FUSE_GETATTR;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->out.numargs = 1;
 	req->out.args[0].size = sizeof(arg);
 	req->out.args[0].value = &arg;
@@ -679,7 +690,6 @@ static int fuse_access(struct inode *inode, int mask)
 	inarg.mask = mask;
 	req->in.h.opcode = FUSE_ACCESS;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->in.numargs = 1;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -820,7 +830,6 @@ static char *read_link(struct dentry *dentry)
 	}
 	req->in.h.opcode = FUSE_READLINK;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->out.argvar = 1;
 	req->out.numargs = 1;
 	req->out.args[0].size = PAGE_SIZE - 1;
@@ -939,7 +948,6 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
 	iattr_to_fattr(attr, &inarg);
 	req->in.h.opcode = FUSE_SETATTR;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->in.numargs = 1;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -1002,7 +1010,6 @@ static int fuse_setxattr(struct dentry *entry, const char *name,
 	inarg.flags = flags;
 	req->in.h.opcode = FUSE_SETXATTR;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->in.numargs = 3;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -1041,7 +1048,6 @@ static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
 	inarg.size = size;
 	req->in.h.opcode = FUSE_GETXATTR;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->in.numargs = 2;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -1091,7 +1097,6 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 	inarg.size = size;
 	req->in.h.opcode = FUSE_LISTXATTR;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->in.numargs = 1;
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
@@ -1135,7 +1140,6 @@ static int fuse_removexattr(struct dentry *entry, const char *name)
 
 	req->in.h.opcode = FUSE_REMOVEXATTR;
 	req->in.h.nodeid = get_node_id(inode);
-	req->inode = inode;
 	req->in.numargs = 1;
 	req->in.args[0].size = strlen(name) + 1;
 	req->in.args[0].value = name;