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authorMarkus Pargmann <mpa@pengutronix.de>2015-07-27 07:36:49 +0200
committerMarkus Pargmann <mpa@pengutronix.de>2016-02-15 10:35:47 +0100
commit37091fdd831f28a6509008542174ed324dd645bc (patch)
treecc38c0cfa314f63e7f63aa309024fe61b15963ea /drivers/block
parentda6ccaaa79caca4f38b540b651238f87215217a2 (diff)
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nbd: Create size change events for userspace
The userspace needs to know when nbd devices are ready for use. Currently no events are created for the userspace which doesn't work for systemd. See the discussion here: https://github.com/systemd/systemd/pull/358 This patch uses a central point to setup the nbd-internal sizes. A ioctl to set a size does not lead to a visible size change. The size of the block device will be kept at 0 until nbd is connected. As soon as it connects, the size will be changed to the real value and a uevent is created. When disconnecting, the blockdevice is set to 0 size and another uevent is generated. Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/nbd.c79
1 files changed, 58 insertions, 21 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 4c5d94146aa3..f6b51d76e578 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -100,6 +100,11 @@ static inline struct device *nbd_to_dev(struct nbd_device *nbd)
return disk_to_dev(nbd->disk);
}
+static bool nbd_is_connected(struct nbd_device *nbd)
+{
+ return !!nbd->task_recv;
+}
+
static const char *nbdcmd_to_ascii(int cmd)
{
switch (cmd) {
@@ -112,6 +117,42 @@ static const char *nbdcmd_to_ascii(int cmd)
return "invalid";
}
+static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
+{
+ bdev->bd_inode->i_size = 0;
+ set_capacity(nbd->disk, 0);
+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+
+ return 0;
+}
+
+static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
+{
+ if (!nbd_is_connected(nbd))
+ return;
+
+ bdev->bd_inode->i_size = nbd->bytesize;
+ set_capacity(nbd->disk, nbd->bytesize >> 9);
+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+}
+
+static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
+ int blocksize, int nr_blocks)
+{
+ int ret;
+
+ ret = set_blocksize(bdev, blocksize);
+ if (ret)
+ return ret;
+
+ nbd->blksize = blocksize;
+ nbd->bytesize = (loff_t)blocksize * (loff_t)nr_blocks;
+
+ nbd_size_update(nbd, bdev);
+
+ return 0;
+}
+
static void nbd_end_request(struct nbd_device *nbd, struct request *req)
{
int error = req->errors ? -EIO : 0;
@@ -401,7 +442,7 @@ static struct device_attribute pid_attr = {
.show = pid_show,
};
-static int nbd_thread_recv(struct nbd_device *nbd)
+static int nbd_thread_recv(struct nbd_device *nbd, struct block_device *bdev)
{
struct request *req;
int ret;
@@ -421,6 +462,8 @@ static int nbd_thread_recv(struct nbd_device *nbd)
return ret;
}
+ nbd_size_update(nbd, bdev);
+
while (1) {
req = nbd_read_stat(nbd);
if (IS_ERR(req)) {
@@ -431,6 +474,8 @@ static int nbd_thread_recv(struct nbd_device *nbd)
nbd_end_request(nbd, req);
}
+ nbd_size_clear(nbd, bdev);
+
device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
nbd->task_recv = NULL;
@@ -707,20 +752,19 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
return err;
}
- case NBD_SET_BLKSIZE:
- nbd->blksize = arg;
- nbd->bytesize &= ~(nbd->blksize-1);
- bdev->bd_inode->i_size = nbd->bytesize;
- set_blocksize(bdev, nbd->blksize);
- set_capacity(nbd->disk, nbd->bytesize >> 9);
- return 0;
+ case NBD_SET_BLKSIZE: {
+ loff_t bsize = nbd->bytesize;
+ do_div(bsize, arg);
+
+ return nbd_size_set(nbd, bdev, arg, bsize);
+ }
case NBD_SET_SIZE:
- nbd->bytesize = arg & ~(nbd->blksize-1);
- bdev->bd_inode->i_size = nbd->bytesize;
- set_blocksize(bdev, nbd->blksize);
- set_capacity(nbd->disk, nbd->bytesize >> 9);
- return 0;
+ return nbd_size_set(nbd, bdev, nbd->blksize,
+ arg / nbd->blksize);
+
+ case NBD_SET_SIZE_BLOCKS:
+ return nbd_size_set(nbd, bdev, nbd->blksize, arg);
case NBD_SET_TIMEOUT:
nbd->xmit_timeout = arg * HZ;
@@ -736,13 +780,6 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
nbd->flags = arg;
return 0;
- case NBD_SET_SIZE_BLOCKS:
- nbd->bytesize = ((u64) arg) * nbd->blksize;
- bdev->bd_inode->i_size = nbd->bytesize;
- set_blocksize(bdev, nbd->blksize);
- set_capacity(nbd->disk, nbd->bytesize >> 9);
- return 0;
-
case NBD_DO_IT: {
struct task_struct *thread;
int error;
@@ -764,7 +801,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
}
nbd_dev_dbg_init(nbd);
- error = nbd_thread_recv(nbd);
+ error = nbd_thread_recv(nbd, bdev);
nbd_dev_dbg_close(nbd);
kthread_stop(thread);