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Message-Id: <1437981176-21061-11-git-send-email-mpa@pengutronix.de>
Date: Mon, 27 Jul 2015 09:12:56 +0200
From: Markus Pargmann <mpa@...gutronix.de>
To: nbd-general@...ts.sourceforge.net
Cc: linux-kernel@...r.kernel.org, kernel@...gutronix.de,
Markus Pargmann <mpa@...gutronix.de>
Subject: [PATCH 10/10] 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@...gutronix.de>
---
drivers/block/nbd.c | 74 ++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 54 insertions(+), 20 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 1176a3b27a7e..95eb2904c324 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -97,6 +97,11 @@ 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) {
@@ -109,6 +114,43 @@ 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_blocksize(bdev, 0);
+ set_capacity(nbd->disk, 0);
+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+
+ return 0;
+}
+
+static int nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
+{
+ int ret;
+
+ if (!nbd_is_connected(nbd))
+ return 0;
+
+ ret = set_blocksize(bdev, nbd->blksize);
+ if (ret)
+ return ret;
+
+ bdev->bd_inode->i_size = nbd->bytesize;
+ set_capacity(nbd->disk, nbd->bytesize >> 9);
+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+
+ return 0;
+}
+
+static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
+ int blocksize, int nr_blocks)
+{
+ nbd->blksize = blocksize;
+ nbd->bytesize = blocksize * nr_blocks;
+
+ return nbd_size_update(nbd, bdev);
+}
+
static void nbd_end_request(struct nbd_device *nbd, struct request *req)
{
int error = req->errors ? -EIO : 0;
@@ -399,7 +441,7 @@ 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;
@@ -417,6 +459,8 @@ 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)) {
@@ -427,6 +471,8 @@ 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;
@@ -681,19 +727,14 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
}
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;
+ return nbd_size_set(nbd, bdev, arg, nbd->bytesize / arg);
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;
@@ -709,13 +750,6 @@ 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;
struct socket *sock;
@@ -746,7 +780,7 @@ 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);
--
2.1.4
--
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