zfs/include/sys
Eric Dillmann 0b4d1b5853 Add snapdev=[hidden|visible] dataset property
The new snapdev dataset property may be set to control the
visibility of zvol snapshot devices.  By default this value
is set to 'hidden' which will prevent zvol snapshots from
appearing under /dev/zvol/ and /dev/<dataset>/.  When set to
'visible' all zvol snapshots for the dataset will be visible.

This functionality was largely added because when automatic
snapshoting is enabled large numbers of read-only zvol snapshots
will be created.  When creating these devices the kernel will
attempt to read their partition tables, and blkid will attempt
to identify any filesystems on those partitions.  This leads
to a variety of issues:

1) The zvol partition tables will be read in the context of
   the `modprobe zfs` for automatically imported pools.  This
   is undesirable and should be done asynchronously, but for
   now reducing the number of visible devices helps.

2) Udev expects to be able to complete its work for a new
   block devices fairly quickly.  When many zvol devices are
   added at the same time this is no longer be true.  It can
   lead to udev timeouts and missing /dev/zvol links.

3) Simply having lots of devices in /dev/ can be aukward from
   a management standpoint.  Hidding the devices your unlikely
   to ever use helps with this.  Any snapshot device which is
   needed can be made visible by changing the snapdev property.

NOTE: This patch changes the default behavior for zvols which
      was effectively 'snapdev=visible'.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1235
Closes #945
Issue #956
Issue #756
2013-03-05 12:37:54 -08:00
..
fm Illumos #2671: zpool import should not fail if vdev ashift has increased 2012-11-15 11:05:59 -08:00
fs Add snapdev=[hidden|visible] dataset property 2013-03-05 12:37:54 -08:00
Makefile.am Illumos #2619 and #2747 2013-01-08 10:35:35 -08:00
arc.h Illumos #3145, #3212 2013-01-08 10:35:44 -08:00
avl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
avl_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
bplist.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
bpobj.h Illumos #3104: eliminate empty bpobjs 2013-01-08 10:35:43 -08:00
bptree.h Illumos #2619 and #2747 2013-01-08 10:35:35 -08:00
dbuf.h Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
ddt.h Add ddt_object_count() error handling 2012-10-29 08:57:45 -07:00
dmu.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
dmu_impl.h Illumos #2703: add mechanism to report ZFS send progress 2012-09-19 13:39:06 -07:00
dmu_objset.h Illumos #3100: zvol rename fails with EBUSY when dirty. 2012-10-03 13:59:02 -07:00
dmu_traverse.h Illumos #2619 and #2747 2013-01-08 10:35:35 -08:00
dmu_tx.h Add --enable-debug-dmu-tx configure option 2012-03-23 12:25:17 -07:00
dmu_zfetch.h Add missing ZFS tunables 2011-05-04 10:02:37 -07:00
dnode.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
dsl_dataset.h Use dsl_dataset_snap_lookup() 2013-01-25 15:07:40 -08:00
dsl_deadlist.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
dsl_deleg.h Illumos #1644, #1645, #1646, #1647, #1708 2012-07-31 09:25:30 -07:00
dsl_dir.h Switch KM_SLEEP to KM_PUSHPAGE 2012-08-27 12:01:37 -07:00
dsl_pool.h Illumos #3104: eliminate empty bpobjs 2013-01-08 10:35:43 -08:00
dsl_prop.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
dsl_scan.h Illumos #2619 and #2747 2013-01-08 10:35:35 -08:00
dsl_synctask.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
efi_partition.h Move partition scanning from userspace to module. 2012-07-17 09:17:31 -07:00
metaslab.h Add FASTWRITE algorithm for synchronous writes. 2012-10-17 08:56:41 -07:00
metaslab_impl.h Add FASTWRITE algorithm for synchronous writes. 2012-10-17 08:56:41 -07:00
nvpair.h Illumos #2619 and #2747 2013-01-08 10:35:35 -08:00
nvpair_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
refcount.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
rrwlock.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
sa.h Add sa_spill_rele() interface 2012-03-07 16:28:00 -08:00
sa_impl.h Illumos #3208 cross-endian incorrect user/group accounting 2013-01-14 09:32:22 -08:00
spa.h Illumos #2619 and #2747 2013-01-08 10:35:35 -08:00
spa_boot.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
spa_impl.h Illumos #3090 and #3102 2013-01-08 10:35:42 -08:00
space_map.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
txg.h Illumos #3086: unnecessarily setting DS_FLAG_INCONSISTENT on async 2013-01-08 10:35:43 -08:00
txg_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
u8_textprep.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
u8_textprep_data.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
uberblock.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
uberblock_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
uio_impl.h Add basic uio support 2011-02-10 09:21:43 -08:00
unique.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
uuid.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
vdev.h Illumos #3090 and #3102 2013-01-08 10:35:42 -08:00
vdev_disk.h Linux 2.6.x compat, blkdev_compat.h 2011-02-23 12:29:38 -08:00
vdev_file.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
vdev_impl.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
xvattr.h Add xvattr support 2011-03-02 11:43:50 -08:00
zap.h Illumos #3104: eliminate empty bpobjs 2013-01-08 10:35:43 -08:00
zap_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zap_leaf.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zfeature.h Illumos #2762: zpool command should have better support for feature flags 2013-01-08 10:35:43 -08:00
zfs_acl.h Fix build failures on PaX/GRSecurity patched kernels 2012-07-17 09:22:43 -07:00
zfs_context.h Remove NPTL_GUARD_WITHIN_STACK 2013-01-29 10:58:20 -08:00
zfs_ctldir.h Linux 3.7 compat, schedule_delayed_work() 2012-12-12 10:47:05 -08:00
zfs_debug.h Cleanly support debug packages 2012-02-27 14:08:17 -08:00
zfs_dir.h Prototype/structure update for Linux 2011-02-10 09:27:21 -08:00
zfs_fuid.h Prototype/structure update for Linux 2011-02-10 09:27:21 -08:00
zfs_ioctl.h Add snapdev=[hidden|visible] dataset property 2013-03-05 12:37:54 -08:00
zfs_onexit.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zfs_rlock.h Range lock performance improvements 2011-03-08 12:44:06 -08:00
zfs_sa.h Implement SA based xattrs 2011-11-28 15:45:51 -08:00
zfs_stat.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zfs_vfsops.h Fix 'zfs rollback' on mounted file systems 2013-01-17 09:51:20 -08:00
zfs_vnops.h Update SAs when an inode is dirtied 2012-12-14 12:18:54 -08:00
zfs_znode.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
zil.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
zil_impl.h Illumos #3086: unnecessarily setting DS_FLAG_INCONSISTENT on async 2013-01-08 10:35:43 -08:00
zio.h Illumos #3035 LZ4 compression support in ZFS and GRUB 2013-01-29 09:28:20 -08:00
zio_checksum.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
zio_compress.h Constify structures containing function pointers 2013-03-04 08:49:32 -08:00
zio_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zpl.h Fix 'zfs rollback' on mounted file systems 2013-01-17 09:51:20 -08:00
zrlock.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
zvol.h Add snapdev=[hidden|visible] dataset property 2013-03-05 12:37:54 -08:00