164 lines
4.4 KiB
Diff
164 lines
4.4 KiB
Diff
From: Markus Pargmann <mpa@pengutronix.de>
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Date: Mon, 27 Jul 2015 07:36:49 +0200
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Subject: nbd: Create size change events for userspace
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Origin: https://git.kernel.org/linus/37091fdd831f28a6509008542174ed324dd645bc
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Bug-Debian: https://bugs.debian.org/812487
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The userspace needs to know when nbd devices are ready for use.
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Currently no events are created for the userspace which doesn't work for
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systemd.
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See the discussion here: https://github.com/systemd/systemd/pull/358
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This patch uses a central point to setup the nbd-internal sizes. A ioctl
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to set a size does not lead to a visible size change. The size of the
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block device will be kept at 0 until nbd is connected. As soon as it
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connects, the size will be changed to the real value and a uevent is
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created. When disconnecting, the blockdevice is set to 0 size and
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another uevent is generated.
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Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
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---
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drivers/block/nbd.c | 79 +++++++++++++++++++++++++++++++++++++++--------------
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1 file changed, 58 insertions(+), 21 deletions(-)
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--- a/drivers/block/nbd.c
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+++ b/drivers/block/nbd.c
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@@ -98,6 +98,11 @@ static inline struct device *nbd_to_dev(
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return disk_to_dev(nbd->disk);
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}
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+static bool nbd_is_connected(struct nbd_device *nbd)
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+{
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+ return !!nbd->task_recv;
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+}
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+
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static const char *nbdcmd_to_ascii(int cmd)
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{
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switch (cmd) {
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@@ -110,6 +115,42 @@ static const char *nbdcmd_to_ascii(int c
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return "invalid";
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}
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+static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
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+{
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+ bdev->bd_inode->i_size = 0;
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+ set_capacity(nbd->disk, 0);
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+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
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+
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+ return 0;
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+}
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+
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+static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
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+{
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+ if (!nbd_is_connected(nbd))
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+ return;
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+
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+ bdev->bd_inode->i_size = nbd->bytesize;
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+ set_capacity(nbd->disk, nbd->bytesize >> 9);
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+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
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+}
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+
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+static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
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+ int blocksize, int nr_blocks)
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+{
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+ int ret;
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+
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+ ret = set_blocksize(bdev, blocksize);
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+ if (ret)
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+ return ret;
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+
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+ nbd->blksize = blocksize;
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+ nbd->bytesize = (loff_t)blocksize * (loff_t)nr_blocks;
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+
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+ nbd_size_update(nbd, bdev);
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+
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+ return 0;
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+}
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+
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static void nbd_end_request(struct nbd_device *nbd, struct request *req)
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{
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int error = req->errors ? -EIO : 0;
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@@ -402,7 +443,7 @@ static struct device_attribute pid_attr
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.show = pid_show,
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};
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-static int nbd_thread_recv(struct nbd_device *nbd)
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+static int nbd_thread_recv(struct nbd_device *nbd, struct block_device *bdev)
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{
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struct request *req;
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int ret;
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@@ -427,6 +468,8 @@ static int nbd_thread_recv(struct nbd_de
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return ret;
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}
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+ nbd_size_update(nbd, bdev);
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+
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while (1) {
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req = nbd_read_stat(nbd);
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if (IS_ERR(req)) {
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@@ -437,6 +480,8 @@ static int nbd_thread_recv(struct nbd_de
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nbd_end_request(nbd, req);
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}
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+ nbd_size_clear(nbd, bdev);
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+
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device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
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spin_lock_irqsave(&nbd->tasks_lock, flags);
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@@ -696,20 +741,19 @@ static int __nbd_ioctl(struct block_devi
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return -EINVAL;
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}
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- case NBD_SET_BLKSIZE:
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- nbd->blksize = arg;
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- nbd->bytesize &= ~(nbd->blksize-1);
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- bdev->bd_inode->i_size = nbd->bytesize;
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- set_blocksize(bdev, nbd->blksize);
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- set_capacity(nbd->disk, nbd->bytesize >> 9);
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- return 0;
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+ case NBD_SET_BLKSIZE: {
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+ loff_t bsize = nbd->bytesize;
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+ do_div(bsize, arg);
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+
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+ return nbd_size_set(nbd, bdev, arg, bsize);
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+ }
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case NBD_SET_SIZE:
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- nbd->bytesize = arg & ~(nbd->blksize-1);
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- bdev->bd_inode->i_size = nbd->bytesize;
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- set_blocksize(bdev, nbd->blksize);
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- set_capacity(nbd->disk, nbd->bytesize >> 9);
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- return 0;
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+ return nbd_size_set(nbd, bdev, nbd->blksize,
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+ arg / nbd->blksize);
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+
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+ case NBD_SET_SIZE_BLOCKS:
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+ return nbd_size_set(nbd, bdev, nbd->blksize, arg);
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case NBD_SET_TIMEOUT:
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nbd->xmit_timeout = arg * HZ;
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@@ -725,13 +769,6 @@ static int __nbd_ioctl(struct block_devi
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nbd->flags = arg;
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return 0;
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- case NBD_SET_SIZE_BLOCKS:
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- nbd->bytesize = ((u64) arg) * nbd->blksize;
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- bdev->bd_inode->i_size = nbd->bytesize;
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- set_blocksize(bdev, nbd->blksize);
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- set_capacity(nbd->disk, nbd->bytesize >> 9);
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- return 0;
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-
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case NBD_DO_IT: {
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struct task_struct *thread;
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struct socket *sock;
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@@ -762,7 +799,7 @@ static int __nbd_ioctl(struct block_devi
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}
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nbd_dev_dbg_init(nbd);
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- error = nbd_thread_recv(nbd);
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+ error = nbd_thread_recv(nbd, bdev);
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nbd_dev_dbg_close(nbd);
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kthread_stop(thread);
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