From: Miklos Szeredi <miklos@szeredi.hu>
This patch fixes an Oops which was caused by premature release of the
fuse_conn object. It does this by introducing reference counting for this
object, instead of using the ->file and ->sb members. Since ->file and ->sb
are never actually dereferenced, these are replaced by ->connected and
->mounted bool members.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
fs/fuse/dev.c | 14 +++++++-------
fs/fuse/fuse_i.h | 13 ++++++++-----
fs/fuse/inode.c | 24 +++++++++---------------
3 files changed, 24 insertions(+), 27 deletions(-)
diff -puN fs/fuse/dev.c~fuse-mount-options-reference-counting-fix fs/fuse/dev.c
--- 25/fs/fuse/dev.c~fuse-mount-options-reference-counting-fix 2005-05-10 02:22:00.000000000 -0700
+++ 25-akpm/fs/fuse/dev.c 2005-05-10 02:22:00.000000000 -0700
@@ -24,7 +24,7 @@ static inline struct fuse_conn *fuse_get
struct fuse_conn *fc;
spin_lock(&fuse_lock);
fc = file->private_data;
- if (fc && !fc->sb)
+ if (fc && !fc->mounted)
fc = NULL;
spin_unlock(&fuse_lock);
return fc;
@@ -176,7 +176,7 @@ static void request_end(struct fuse_conn
spin_unlock(&fuse_lock);
if (req->background) {
down_read(&fc->sbput_sem);
- if (fc->sb)
+ if (fc->mounted)
fuse_release_background(req);
up_read(&fc->sbput_sem);
}
@@ -306,7 +306,7 @@ static void request_send_wait(struct fus
{
req->isreply = 1;
spin_lock(&fuse_lock);
- if (!fc->file)
+ if (!fc->connected)
req->out.h.error = -ENOTCONN;
else if (fc->conn_error)
req->out.h.error = -ECONNREFUSED;
@@ -339,7 +339,7 @@ void request_send_nonint(struct fuse_con
static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
{
spin_lock(&fuse_lock);
- if (fc->file) {
+ if (fc->connected) {
queue_request(fc, req);
spin_unlock(&fuse_lock);
} else {
@@ -592,7 +592,7 @@ static void request_wait(struct fuse_con
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&fc->waitq, &wait);
- while (fc->sb && list_empty(&fc->pending)) {
+ while (fc->mounted && list_empty(&fc->pending)) {
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current))
break;
@@ -631,7 +631,7 @@ static ssize_t fuse_dev_readv(struct fil
goto err_unlock;
request_wait(fc);
err = -ENODEV;
- if (!fc->sb)
+ if (!fc->mounted)
goto err_unlock;
err = -ERESTARTSYS;
if (list_empty(&fc->pending))
@@ -848,7 +848,7 @@ static int fuse_dev_release(struct inode
spin_lock(&fuse_lock);
fc = file->private_data;
if (fc) {
- fc->file = NULL;
+ fc->connected = 0;
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
fuse_release_conn(fc);
diff -puN fs/fuse/fuse_i.h~fuse-mount-options-reference-counting-fix fs/fuse/fuse_i.h
--- 25/fs/fuse/fuse_i.h~fuse-mount-options-reference-counting-fix 2005-05-10 02:22:00.000000000 -0700
+++ 25-akpm/fs/fuse/fuse_i.h 2005-05-10 02:22:00.000000000 -0700
@@ -196,11 +196,8 @@ struct fuse_req {
* unmounted.
*/
struct fuse_conn {
- /** The superblock of the mounted filesystem */
- struct super_block *sb;
-
- /** The opened client device */
- struct file *file;
+ /** Reference count */
+ int count;
/** The user id for this mount */
uid_t user_id;
@@ -237,6 +234,12 @@ struct fuse_conn {
/** The next unique request id */
int reqctr;
+ /** Mount is active */
+ unsigned mounted : 1;
+
+ /** Connection established */
+ unsigned connected : 1;
+
/** Connection failed (version mismatch) */
unsigned conn_error : 1;
diff -puN fs/fuse/inode.c~fuse-mount-options-reference-counting-fix fs/fuse/inode.c
--- 25/fs/fuse/inode.c~fuse-mount-options-reference-counting-fix 2005-05-10 02:22:00.000000000 -0700
+++ 25-akpm/fs/fuse/inode.c 2005-05-10 02:22:00.000000000 -0700
@@ -84,8 +84,8 @@ void fuse_send_forget(struct fuse_conn *
static void fuse_clear_inode(struct inode *inode)
{
- struct fuse_conn *fc = get_fuse_conn(inode);
- if (fc && (inode->i_sb->s_flags & MS_ACTIVE)) {
+ if (inode->i_sb->s_flags & MS_ACTIVE) {
+ struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
fi->forget_req = NULL;
@@ -196,14 +196,13 @@ static void fuse_put_super(struct super_
struct fuse_req, bg_entry));
spin_lock(&fuse_lock);
- fc->sb = NULL;
+ fc->mounted = 0;
fc->user_id = 0;
fc->flags = 0;
/* Flush all readers on this fs */
wake_up_all(&fc->waitq);
up_write(&fc->sbput_sem);
fuse_release_conn(fc);
- *get_fuse_conn_super_p(sb) = NULL;
spin_unlock(&fuse_lock);
}
@@ -355,7 +354,8 @@ static void free_conn(struct fuse_conn *
/* Must be called with the fuse lock held */
void fuse_release_conn(struct fuse_conn *fc)
{
- if (!fc->sb && !fc->file)
+ fc->count--;
+ if (!fc->count)
free_conn(fc);
}
@@ -367,10 +367,6 @@ static struct fuse_conn *new_conn(void)
if (fc != NULL) {
int i;
memset(fc, 0, sizeof(*fc));
- fc->sb = NULL;
- fc->file = NULL;
- fc->flags = 0;
- fc->user_id = 0;
init_waitqueue_head(&fc->waitq);
INIT_LIST_HEAD(&fc->pending);
INIT_LIST_HEAD(&fc->processing);
@@ -408,8 +404,10 @@ static struct fuse_conn *get_conn(struct
fc = ERR_PTR(-EINVAL);
} else {
file->private_data = fc;
- fc->sb = sb;
- fc->file = file;
+ *get_fuse_conn_super_p(sb) = fc;
+ fc->mounted = 1;
+ fc->connected = 1;
+ fc->count = 2;
}
spin_unlock(&fuse_lock);
return fc;
@@ -464,8 +462,6 @@ static int fuse_fill_super(struct super_
fc->flags = d.flags;
fc->user_id = d.user_id;
- *get_fuse_conn_super_p(sb) = fc;
-
err = -ENOMEM;
root = get_root_inode(sb, d.rootmode);
if (root == NULL)
@@ -481,10 +477,8 @@ static int fuse_fill_super(struct super_
err:
spin_lock(&fuse_lock);
- fc->sb = NULL;
fuse_release_conn(fc);
spin_unlock(&fuse_lock);
- *get_fuse_conn_super_p(sb) = NULL;
return err;
}
_