Remove ZFS_IOC_*_MINOR ioctl()s #1969
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@dweeezil I thought you might be interested in this since you did all the libzfs_core work. This should bring or minor handling back in sync with FreeBSD / Illumos. |
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@behlendorf This looks good to me. While doing the libzfs_core work, and having to add minor creation in at least one place, I had wondered why it wasn't all done in the kernel. It's nice to get this re-aligned with Illumos and FreeBSD. |
Early versions of ZFS coordinated the creation and destruction of device minors from userspace. This was inherently racy and in late 2009 these ioctl()s were removed leaving everything up to the kernel. This significantly simplified the code. However, we never picked up these changes in ZoL since we'd already significantly adjusted this code for Linux. This patch aims to rectify that by finally removing ZFC_IOC_*_MINOR ioctl()s and moving all the functionality down in to the kernel. Since this cleanup will change the kernel/user ABI it's being done in the same tag as the previous libzfs_core ABI changes. This will minimize, but not eliminate, the disruption to end users. Once merged ZoL, Illumos, and FreeBSD will basically be back in sync in regards to handling ZVOLs in the common code. While each platform must have its own custom zvol.c implemenation the interfaces provided are consistent. NOTES: 1) This patch introduces one subtle change in behavior which could not be easily avoided. Prior to this change callers of 'zfs create -V ...' were guaranteed that upon exit the /dev/zvol/ block device link would be created or an error returned. That's no longer the case. The utilities will no longer block waiting for the symlink to be created. Callers are now responsible for blocking, this is why a 'udev_wait' call was added to the 'label' function in scripts/common.sh. 2) The read-only behavior of a ZVOL now solely depends on if the ZVOL_RDONLY bit is set in zv->zv_flags. The redundant policy setting in the gendisk structure was removed. This both simplifies the code and allows us to safely leverage set_disk_ro() to issue a KOBJ_CHANGE uevent. See the comment in the code for futher details on this. 3) Because __zvol_create_minor() and zvol_alloc() may now be called in a sync task they must use KM_PUSHPAGE. References: illumos-gate/illumos@681d9761e8516a7dc5ab6589e2dfe717777e1123 Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#1862
The Snapshots section of the zfs(8) man page is incorrect and should have been updated as part of openzfs#1312. Snapshots of volumes can be accessed independently and their visibility is determined by the 'snapdev=hidden|visible' property. This is analogous to the existing 'snapdir=hidden|visible' property. Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#1921
Update zvol.c to conform to the style guidelines, verified by running cstyle.pl on the source file. This patch contains no functional changes. Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#1821
When running zconfig.sh test 7 and 8 cause the following warning to be printed to the console. It's caused because we're snapshoting a mounted ext2 filesystem which is not in a 'clean' state. This is to be expected since we have no guarentees about the on-disk consistency of the filesystem. EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended To silence the warning and preserve the intent of these test cases they have been updated to unmount the filesystem prior to snapshoting them. This ensures the ext2 filesystem is in a consistent state when the snapshot is taken. Signed-off-by: Brian Behlendorf <[email protected]> Issue openzfs#1972
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The commit message for faac329 has illumos and illumos-gate transposed in the reference link. |
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Some overdue cleanup to bring the ZoL utilities back in sync with FreeBSD and Illumos in regards to zvol minor handling. Because this patch adjusts the ZFS kernel/user ioctl() ABI we wanted to get this work done prior to 0.6.3 being tagged because it already contains the libzfs_core ABI changes.
The patch stack also includes some additional zvol related cleanup and man page updates.