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authorDavid Herrmann <dh.herrmann@googlemail.com>2012-11-17 12:45:48 +0100
committerMiklos Szeredi <mszeredi@suse.cz>2013-01-17 13:04:57 +0100
commit30783587b0f318b9e2e165f34cf5dfd9425a4904 (patch)
tree4aeaf43d76cda5cad2c968214c1efce047f53f71 /fs
parent8ce03fd76d323526a693d05d85296ef07a387a9f (diff)
cuse: do not register multiple devices with identical names
Sysfs doesn't allow two devices with the same name, but we register a sysfs entry for each cuse device without checking for name collisions. This extends the registration to first check whether the name was already registered. To avoid race-conditions between the name-check and linking the device, we need to protect the whole registration with a mutex. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs')
-rw-r--r--fs/fuse/cuse.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index 048e89f2508..2a2797e2abc 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -304,14 +304,14 @@ static void cuse_gendev_release(struct device *dev)
*/
static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
{
- struct cuse_conn *cc = fc_to_cc(fc);
+ struct cuse_conn *cc = fc_to_cc(fc), *pos;
struct cuse_init_out *arg = req->out.args[0].value;
struct page *page = req->pages[0];
struct cuse_devinfo devinfo = { };
struct device *dev;
struct cdev *cdev;
dev_t devt;
- int rc;
+ int rc, i;
if (req->out.h.error ||
arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) {
@@ -355,15 +355,24 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
dev_set_drvdata(dev, cc);
dev_set_name(dev, "%s", devinfo.name);
+ mutex_lock(&cuse_lock);
+
+ /* make sure the device-name is unique */
+ for (i = 0; i < CUSE_CONNTBL_LEN; ++i) {
+ list_for_each_entry(pos, &cuse_conntbl[i], list)
+ if (!strcmp(dev_name(pos->dev), dev_name(dev)))
+ goto err_unlock;
+ }
+
rc = device_add(dev);
if (rc)
- goto err_device;
+ goto err_unlock;
/* register cdev */
rc = -ENOMEM;
cdev = cdev_alloc();
if (!cdev)
- goto err_device;
+ goto err_unlock;
cdev->owner = THIS_MODULE;
cdev->ops = &cuse_frontend_fops;
@@ -376,7 +385,6 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
cc->cdev = cdev;
/* make the device available */
- mutex_lock(&cuse_lock);
list_add(&cc->list, cuse_conntbl_head(devt));
mutex_unlock(&cuse_lock);
@@ -390,7 +398,8 @@ out:
err_cdev:
cdev_del(cdev);
-err_device:
+err_unlock:
+ mutex_unlock(&cuse_lock);
put_device(dev);
err_region:
unregister_chrdev_region(devt, 1);