From 498ef5c777d9c89693b70cc453b40c392120ea1b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 30 Mar 2022 07:29:14 +0200 Subject: [PATCH] loop: suppress uevents while reconfiguring the device Currently, udev change event is generated for a loop device before the device is ready for IO. Due to serialization on lo->lo_mutex in lo_open() this does not matter because anybody is able to open the device and do IO only after the configuration is finished. However this synchronization in lo_open() is going away so make sure userspace reacting to the change event will see the new device state by generating the event only when the device is setup. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220330052917.2566582-13-hch@lst.de Signed-off-by: Jens Axboe --- drivers/block/loop.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index e0c8768..ef76923 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -569,6 +569,10 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, if (!file) return -EBADF; + + /* suppress uevents while reconfiguring the device */ + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); + is_loop = is_loop_device(file); error = loop_global_lock_killable(lo, is_loop); if (error) @@ -623,13 +627,18 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, fput(old_file); if (partscan) loop_reread_partitions(lo); - return 0; + + error = 0; +done: + /* enable and uncork uevent now that we are done */ + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); + return error; out_err: loop_global_unlock(lo, is_loop); out_putf: fput(file); - return error; + goto done; } /* loop sysfs attributes */ @@ -994,6 +1003,9 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, /* This is safe, since we have a reference from open(). */ __module_get(THIS_MODULE); + /* suppress uevents while reconfiguring the device */ + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); + /* * If we don't hold exclusive handle for the device, upgrade to it * here to avoid changing device under exclusive owner. @@ -1096,7 +1108,12 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, loop_reread_partitions(lo); if (!(mode & FMODE_EXCL)) bd_abort_claiming(bdev, loop_configure); - return 0; + + error = 0; +done: + /* enable and uncork uevent now that we are done */ + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); + return error; out_unlock: loop_global_unlock(lo, is_loop); @@ -1107,7 +1124,7 @@ out_putf: fput(file); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); - return error; + goto done; } static void __loop_clr_fd(struct loop_device *lo, bool release) -- 2.7.4