[PATCH 6/10] fuse: use a per-mount spinlock

From: Miklos Szeredi
Date: Fri Mar 31 2006 - 12:54:04 EST

Remove the global spinlock in favor of a per-mount one.

This patch is basically find & replace. The difficult part has
already been done by the previous patch.

Signed-off-by: Miklos Szeredi <miklos@xxxxxxxxxx>

Index: linux/fs/fuse/dev.c
===================================================================
--- linux.orig/fs/fuse/dev.c 2006-03-31 18:55:31.000000000 +0200
+++ linux/fs/fuse/dev.c 2006-03-31 18:55:31.000000000 +0200
@@ -1,6 +1,6 @@
/*
FUSE: Filesystem in Userspace
- Copyright (C) 2001-2005 Miklos Szeredi <miklos@xxxxxxxxxx>
+ Copyright (C) 2001-2006 Miklos Szeredi <miklos@xxxxxxxxxx>

This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
@@ -94,11 +94,11 @@ static struct fuse_req *do_get_request(s
{
struct fuse_req *req;

- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
BUG_ON(list_empty(&fc->unused_list));
req = list_entry(fc->unused_list.next, struct fuse_req, list);
list_del_init(&req->list);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
fuse_request_init(req);
req->preallocated = 1;
req->in.h.uid = current->fsuid;
@@ -124,7 +124,7 @@ struct fuse_req *fuse_get_request(struct
return do_get_request(fc);
}

-/* Must be called with fuse_lock held */
+/* Must be called with fc->lock held */
static void fuse_putback_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (req->preallocated) {
@@ -143,9 +143,9 @@ static void fuse_putback_request(struct
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (atomic_dec_and_test(&req->count)) {
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
fuse_putback_request(fc, req);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}
}

@@ -155,15 +155,15 @@ static void fuse_put_request_locked(stru
fuse_putback_request(fc, req);
}

-void fuse_release_background(struct fuse_req *req)
+void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req)
{
iput(req->inode);
iput(req->inode2);
if (req->file)
fput(req->file);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
list_del(&req->bg_entry);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}

/*
@@ -182,7 +182,7 @@ void fuse_release_background(struct fuse
* interrupted and put in the background, it will return with an error
* and hence never be reset and reused.
*
- * Called with fuse_lock, unlocks it
+ * Called with fc->lock, unlocks it
*/
static void request_end(struct fuse_conn *fc, struct fuse_req *req)
{
@@ -191,14 +191,14 @@ static void request_end(struct fuse_conn
if (!req->background) {
wake_up(&req->waitq);
fuse_put_request_locked(fc, req);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
} else {
void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
req->end = NULL;
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
down_read(&fc->sbput_sem);
if (fc->mounted)
- fuse_release_background(req);
+ fuse_release_background(fc, req);
up_read(&fc->sbput_sem);
if (end)
end(fc, req);
@@ -248,16 +248,16 @@ static void background_request(struct fu
get_file(req->file);
}

-/* Called with fuse_lock held. Releases, and then reacquires it. */
+/* Called with fc->lock held. Releases, and then reacquires it. */
static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
{
sigset_t oldset;

- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
block_sigs(&oldset);
wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
restore_sigs(&oldset);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
if (req->state == FUSE_REQ_FINISHED && !req->interrupted)
return;

@@ -271,9 +271,9 @@ static void request_wait_answer(struct f
locked state, there mustn't be any filesystem
operation (e.g. page fault), since that could lead
to deadlock */
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
wait_event(req->waitq, !req->locked);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
}
if (req->state == FUSE_REQ_PENDING) {
list_del(&req->list);
@@ -324,7 +324,7 @@ static void queue_request(struct fuse_co
void request_send(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
if (!fc->connected)
req->out.h.error = -ENOTCONN;
else if (fc->conn_error)
@@ -337,15 +337,15 @@ void request_send(struct fuse_conn *fc,

request_wait_answer(fc, req);
}
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}

static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
{
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
if (fc->connected) {
queue_request(fc, req);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
} else {
req->out.h.error = -ENOTCONN;
request_end(fc, req);
@@ -361,9 +361,9 @@ void request_send_noreply(struct fuse_co
void request_send_background(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
background_request(fc, req);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
request_send_nowait(fc, req);
}

@@ -372,16 +372,16 @@ void request_send_background(struct fuse
* anything that could cause a page-fault. If the request was already
* interrupted bail out.
*/
-static int lock_request(struct fuse_req *req)
+static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
{
int err = 0;
if (req) {
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
if (req->interrupted)
err = -ENOENT;
else
req->locked = 1;
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}
return err;
}
@@ -391,18 +391,19 @@ static int lock_request(struct fuse_req
* requester thread is currently waiting for it to be unlocked, so
* wake it up.
*/
-static void unlock_request(struct fuse_req *req)
+static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (req) {
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
req->locked = 0;
if (req->interrupted)
wake_up(&req->waitq);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}
}

struct fuse_copy_state {
+ struct fuse_conn *fc;
int write;
struct fuse_req *req;
const struct iovec *iov;
@@ -415,11 +416,12 @@ struct fuse_copy_state {
unsigned len;
};

-static void fuse_copy_init(struct fuse_copy_state *cs, int write,
- struct fuse_req *req, const struct iovec *iov,
- unsigned long nr_segs)
+static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
+ int write, struct fuse_req *req,
+ const struct iovec *iov, unsigned long nr_segs)
{
memset(cs, 0, sizeof(*cs));
+ cs->fc = fc;
cs->write = write;
cs->req = req;
cs->iov = iov;
@@ -449,7 +451,7 @@ static int fuse_copy_fill(struct fuse_co
unsigned long offset;
int err;

- unlock_request(cs->req);
+ unlock_request(cs->fc, cs->req);
fuse_copy_finish(cs);
if (!cs->seglen) {
BUG_ON(!cs->nr_segs);
@@ -472,7 +474,7 @@ static int fuse_copy_fill(struct fuse_co
cs->seglen -= cs->len;
cs->addr += cs->len;

- return lock_request(cs->req);
+ return lock_request(cs->fc, cs->req);
}

/* Do as much copy to/from userspace buffer as we can */
@@ -584,9 +586,9 @@ static void request_wait(struct fuse_con
if (signal_pending(current))
break;

- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
schedule();
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&fc->waitq, &wait);
@@ -614,7 +616,7 @@ static ssize_t fuse_dev_readv(struct fil
return -EPERM;

restart:
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
err = -EAGAIN;
if((file->f_flags & O_NONBLOCK) && fc->connected &&
list_empty(&fc->pending))
@@ -643,14 +645,14 @@ static ssize_t fuse_dev_readv(struct fil
request_end(fc, req);
goto restart;
}
- spin_unlock(&fuse_lock);
- fuse_copy_init(&cs, 1, req, iov, nr_segs);
+ spin_unlock(&fc->lock);
+ fuse_copy_init(&cs, fc, 1, req, iov, nr_segs);
err = fuse_copy_one(&cs, &in->h, sizeof(in->h));
if (!err)
err = fuse_copy_args(&cs, in->numargs, in->argpages,
(struct fuse_arg *) in->args, 0);
fuse_copy_finish(&cs);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
req->locked = 0;
if (!err && req->interrupted)
err = -ENOENT;
@@ -665,12 +667,12 @@ static ssize_t fuse_dev_readv(struct fil
else {
req->state = FUSE_REQ_SENT;
list_move_tail(&req->list, &fc->processing);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}
return reqsize;

err_unlock:
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
return err;
}

@@ -739,7 +741,7 @@ static ssize_t fuse_dev_writev(struct fi
if (!fc)
return -ENODEV;

- fuse_copy_init(&cs, 0, NULL, iov, nr_segs);
+ fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs);
if (nbytes < sizeof(struct fuse_out_header))
return -EINVAL;

@@ -751,7 +753,7 @@ static ssize_t fuse_dev_writev(struct fi
oh.len != nbytes)
goto err_finish;

- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
err = -ENOENT;
if (!fc->connected)
goto err_unlock;
@@ -762,9 +764,9 @@ static ssize_t fuse_dev_writev(struct fi
goto err_unlock;

if (req->interrupted) {
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
fuse_copy_finish(&cs);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
request_end(fc, req);
return -ENOENT;
}
@@ -772,12 +774,12 @@ static ssize_t fuse_dev_writev(struct fi
req->out.h = oh;
req->locked = 1;
cs.req = req;
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);

err = copy_out_args(&cs, &req->out, nbytes);
fuse_copy_finish(&cs);

- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
req->locked = 0;
if (!err) {
if (req->interrupted)
@@ -789,7 +791,7 @@ static ssize_t fuse_dev_writev(struct fi
return err ? err : nbytes;

err_unlock:
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
err_finish:
fuse_copy_finish(&cs);
return err;
@@ -813,12 +815,12 @@ static unsigned fuse_dev_poll(struct fil

poll_wait(file, &fc->waitq, wait);

- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
if (!fc->connected)
mask = POLLERR;
else if (!list_empty(&fc->pending))
mask |= POLLIN | POLLRDNORM;
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);

return mask;
}
@@ -826,7 +828,7 @@ static unsigned fuse_dev_poll(struct fil
/*
* Abort all requests on the given list (pending or processing)
*
- * This function releases and reacquires fuse_lock
+ * This function releases and reacquires fc->lock
*/
static void end_requests(struct fuse_conn *fc, struct list_head *head)
{
@@ -835,7 +837,7 @@ static void end_requests(struct fuse_con
req = list_entry(head->next, struct fuse_req, list);
req->out.h.error = -ECONNABORTED;
request_end(fc, req);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
}
}

@@ -866,10 +868,10 @@ static void end_io_requests(struct fuse_
req->end = NULL;
/* The end function will consume this reference */
__fuse_get_request(req);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
wait_event(req->waitq, !req->locked);
end(fc, req);
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
}
}
}
@@ -896,7 +898,7 @@ static void end_io_requests(struct fuse_
*/
void fuse_abort_conn(struct fuse_conn *fc)
{
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
if (fc->connected) {
fc->connected = 0;
end_io_requests(fc);
@@ -905,18 +907,18 @@ void fuse_abort_conn(struct fuse_conn *f
wake_up_all(&fc->waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
}

static int fuse_dev_release(struct inode *inode, struct file *file)
{
struct fuse_conn *fc = fuse_get_conn(file);
if (fc) {
- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
fc->connected = 0;
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
fasync_helper(-1, file, 0, &fc->fasync);
kobject_put(&fc->kobj);
}
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h 2006-03-31 18:55:31.000000000 +0200
+++ linux/fs/fuse/fuse_i.h 2006-03-31 18:55:31.000000000 +0200
@@ -1,6 +1,6 @@
/*
FUSE: Filesystem in Userspace
- Copyright (C) 2001-2005 Miklos Szeredi <miklos@xxxxxxxxxx>
+ Copyright (C) 2001-2006 Miklos Szeredi <miklos@xxxxxxxxxx>

This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
@@ -144,7 +144,7 @@ struct fuse_req {
/*
* The following bitfields are either set once before the
* request is queued or setting/clearing them is protected by
- * fuse_lock
+ * fuse_conn->lock
*/

/** True if the request has reply */
@@ -213,6 +213,9 @@ struct fuse_req {
* unmounted.
*/
struct fuse_conn {
+ /** Lock protecting accessess to members of this structure */
+ spinlock_t lock;
+
/** The user id for this mount */
uid_t user_id;

@@ -352,21 +355,6 @@ static inline u64 get_node_id(struct ino
extern const struct file_operations fuse_dev_operations;

/**
- * This is the single global spinlock which protects FUSE's structures
- *
- * The following data is protected by this lock:
- *
- * - the private_data field of the device file
- * - the s_fs_info field of the super block
- * - unused_list, pending, processing lists in fuse_conn
- * - background list in fuse_conn
- * - the unique request ID counter reqctr in fuse_conn
- * - the sb (super_block) field in fuse_conn
- * - the file (device file) field in fuse_conn
- */
-extern spinlock_t fuse_lock;
-
-/**
* Get a filled in inode
*/
struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
@@ -490,7 +478,7 @@ void request_send_background(struct fuse
/**
* Release inodes and file associated with background request
*/
-void fuse_release_background(struct fuse_req *req);
+void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req);

/* Abort all requests */
void fuse_abort_conn(struct fuse_conn *fc);
Index: linux/fs/fuse/inode.c
===================================================================
--- linux.orig/fs/fuse/inode.c 2006-03-31 18:55:31.000000000 +0200
+++ linux/fs/fuse/inode.c 2006-03-31 18:55:31.000000000 +0200
@@ -1,6 +1,6 @@
/*
FUSE: Filesystem in Userspace
- Copyright (C) 2001-2005 Miklos Szeredi <miklos@xxxxxxxxxx>
+ Copyright (C) 2001-2006 Miklos Szeredi <miklos@xxxxxxxxxx>

This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
@@ -22,7 +22,6 @@ MODULE_AUTHOR("Miklos Szeredi <miklos@sz
MODULE_DESCRIPTION("Filesystem in Userspace");
MODULE_LICENSE("GPL");

-spinlock_t fuse_lock;
static kmem_cache_t *fuse_inode_cachep;
static struct subsystem connections_subsys;

@@ -207,13 +206,14 @@ static void fuse_put_super(struct super_

down_write(&fc->sbput_sem);
while (!list_empty(&fc->background))
- fuse_release_background(list_entry(fc->background.next,
+ fuse_release_background(fc,
+ list_entry(fc->background.next,
struct fuse_req, bg_entry));

- spin_lock(&fuse_lock);
+ spin_lock(&fc->lock);
fc->mounted = 0;
fc->connected = 0;
- spin_unlock(&fuse_lock);
+ spin_unlock(&fc->lock);
up_write(&fc->sbput_sem);
/* Flush all readers on this fs */
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
@@ -388,6 +388,7 @@ static struct fuse_conn *new_conn(void)
fc = kzalloc(sizeof(*fc), GFP_KERNEL);
if (fc) {
int i;
+ spin_lock_init(&fc->lock);
init_waitqueue_head(&fc->waitq);
INIT_LIST_HEAD(&fc->pending);
INIT_LIST_HEAD(&fc->processing);
@@ -734,7 +735,6 @@ static int __init fuse_init(void)
printk("fuse init (API version %i.%i)\n",
FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);

- spin_lock_init(&fuse_lock);
res = fuse_fs_init();
if (res)
goto err;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/