From 5a25f0eb707bbb4a5aaaf19c933605a6dbaf77a5 Mon Sep 17 00:00:00 2001 From: Jonathan E Brassow Date: Mon, 31 Oct 2011 20:21:24 +0000 Subject: dm log userspace: add log device dependency Allow userspace dm log implementations to register their log device so it is no longer missing from the list of device dependencies. When device mapper targets use a device they normally call dm_get_device which includes it in the device list returned to userspace applications such as LVM through the DM_TABLE_DEPS ioctl. Userspace log devices don't use dm_get_device as userspace opens them so they are missing from the list of dependencies. This patch extends the DM_ULOG_CTR operation to allow userspace to respond with the name of the log device (if appropriate) to be registered via 'dm_get_device'. DM_ULOG_REQUEST_VERSION is incremented. This is backwards compatible. If the kernel and userspace log server have both been updated, the new information will be passed down to the kernel and the device will be registered. If the kernel is new, but the log server is old, the log server will not pass down any device information and the kernel will simply bypass the device registration as before. If the kernel is old but the log server is new, the log server will see the old version number and not pass the device info. Signed-off-by: Jonathan Brassow Signed-off-by: Alasdair G Kergon --- drivers/md/dm-log-userspace-base.c | 35 ++++++++++++++++++++++++++++++++--- 1 file changed, 32 insertions(+), 3 deletions(-) (limited to 'drivers/md/dm-log-userspace-base.c') diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c index 3c27978890b7..8db3862dade5 100644 --- a/drivers/md/dm-log-userspace-base.c +++ b/drivers/md/dm-log-userspace-base.c @@ -30,6 +30,7 @@ struct flush_entry { struct log_c { struct dm_target *ti; + struct dm_dev *log_dev; uint32_t region_size; region_t region_count; uint64_t luid; @@ -161,13 +162,15 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, struct log_c *lc = NULL; uint64_t rdata; size_t rdata_size = sizeof(rdata); + char *devices_rdata = NULL; + size_t devices_rdata_size = DM_NAME_LEN; if (argc < 3) { DMWARN("Too few arguments to userspace dirty log"); return -EINVAL; } - lc = kmalloc(sizeof(*lc), GFP_KERNEL); + lc = kzalloc(sizeof(*lc), GFP_KERNEL); if (!lc) { DMWARN("Unable to allocate userspace log context."); return -ENOMEM; @@ -195,9 +198,19 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, return str_size; } - /* Send table string */ + devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL); + if (!devices_rdata) { + DMERR("Failed to allocate memory for device information"); + r = -ENOMEM; + goto out; + } + + /* + * Send table string and get back any opened device. + */ r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR, - ctr_str, str_size, NULL, NULL); + ctr_str, str_size, + devices_rdata, &devices_rdata_size); if (r < 0) { if (r == -ESRCH) @@ -220,7 +233,20 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, lc->region_size = (uint32_t)rdata; lc->region_count = dm_sector_div_up(ti->len, lc->region_size); + if (devices_rdata_size) { + if (devices_rdata[devices_rdata_size - 1] != '\0') { + DMERR("DM_ULOG_CTR device return string not properly terminated"); + r = -EINVAL; + goto out; + } + r = dm_get_device(ti, devices_rdata, + dm_table_get_mode(ti->table), &lc->log_dev); + if (r) + DMERR("Failed to register %s with device-mapper", + devices_rdata); + } out: + kfree(devices_rdata); if (r) { kfree(lc); kfree(ctr_str); @@ -241,6 +267,9 @@ static void userspace_dtr(struct dm_dirty_log *log) NULL, 0, NULL, NULL); + if (lc->log_dev) + dm_put_device(lc->ti, lc->log_dev); + kfree(lc->usr_argv_str); kfree(lc); -- cgit v1.2.3