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| author | Peter Rajnoha <prajnoha@redhat.com> | 2016-08-23 15:57:47 +0200 |
|---|---|---|
| committer | Peter Rajnoha <prajnoha@redhat.com> | 2016-08-23 15:58:03 +0200 |
| commit | db0e34535c82cfb73af19a7673de82881ad2468c (patch) | |
| tree | 61141410f702e2729b225c3494d55440c14c7405 /libdm/libdevmapper.h | |
| parent | b975532433dcbcc01e3cc0ebe8c6165e2d6470f8 (diff) | |
| download | lvm2-db0e34535c82cfb73af19a7673de82881ad2468c.tar.gz | |
libdm: add some comments about DM_UDEV_DISABLE_LIBRARY_FALLBACK flag
Diffstat (limited to 'libdm/libdevmapper.h')
| -rw-r--r-- | libdm/libdevmapper.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h index 5246b1528..579048690 100644 --- a/libdm/libdevmapper.h +++ b/libdm/libdevmapper.h @@ -216,6 +216,7 @@ int dm_task_set_major_minor(struct dm_task *dmt, int major, int minor, int allow int dm_task_set_uid(struct dm_task *dmt, uid_t uid); int dm_task_set_gid(struct dm_task *dmt, gid_t gid); int dm_task_set_mode(struct dm_task *dmt, mode_t mode); +/* See also description for DM_UDEV_DISABLE_LIBRARY_FALLBACK flag! */ int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags); int dm_task_set_event_nr(struct dm_task *dmt, uint32_t event_nr); int dm_task_set_geometry(struct dm_task *dmt, const char *cylinders, const char *heads, const char *sectors, const char *start); @@ -3496,7 +3497,18 @@ struct dm_pool *dm_config_memory(struct dm_config_tree *cft); * DM_UDEV_DISABLE_LIBRARY_FALLBACK is set in case we need to disable * libdevmapper's node management. We will rely on udev completely * and there will be no fallback action provided by libdevmapper if - * udev does something improperly. + * udev does something improperly. Using the library fallback code has + * a consequence that you need to take into account: any device node + * or symlink created without udev is not recorded in udev database + * which other applications may read to get complete list of devices. + * For this reason, use of DM_UDEV_DISABLE_LIBRARY_FALLBACK is + * recommended on systems where udev is used. Keep library fallback + * enabled just for exceptional cases where you need to debug udev-related + * problems. If you hit such problems, please contact us through upstream + * LVM2 development mailing list (see also README file). This flag is + * currently not set by default in libdevmapper so you need to set it + * explicitly if you're sure that udev is behaving correctly on your + * setups. */ #define DM_UDEV_DISABLE_LIBRARY_FALLBACK 0x0020 /* |