If a multipath device is removed, and check_path() checks one of its paths before multipathd processes either the uevent or the dm event from removing it, multipathd will recreate the removed device. This happens because check_path() will continute to check the removed device's former paths until an event arrives removing the device. A missing multpath device will cause the update_multipath_strings() call to fail, setting pp->dmstate to PSTATE_UNDEF. If the path is up, this dmstate will cause reinstate_path() to be called, which will also fail, because the multipath device doesn't exist. This will trigger a reload, restoring the recently removed device. This patchset handles this is two ways. The first two patches directly fix these issues in check_path(), so that a missing multipath device will no longer get recreated when checking one of its former paths. The other 5 patches add a "multipathd del maps" command, and make the mutipath command delegate flush operations to multipathd so multipathd's state remains in sync with the kernel's, while doing removes. Changes from v1: 0001: This is completely different. I've change how patch 0002 detects when a multipath device has disappeared. Instead of do_get_info, I need more return values on dm_get_map/status, and the update_multipath_* functions. I have used symbolic return values, which was the objection to the previous patch. I tried to picked generic enough names that they could be used for other devmapper.c functions as well. 0002: At Martin's suggestion, multipath now differentiates between dm failures and a missing multipath device in update_multipath_strings(). So there is no need to recheck if the device is missing. 0006: Added some man page info that was previously in patch 0007 0007: Removed mentions of the -D option in the man page and usage output. I did not change anything about suspending the device on remove. It was not obvious how to break that up between multipath and multipathd, and there are likely still some conversations to be had about what we need to do to remove a device in multipath, and in what order. So, for now, I just kept all those functions the same, and just added the code necessary to make multpathd work with them correctly, as is. Benjamin Marzinski (7): libmultipath: make dm_get_map/status return codes symbolic multipathd: fix check_path errors with removed map libmultipath: make dm_flush_maps only return 0 on success multipathd: add "del maps" multipathd command multipath: make flushing maps work like other commands multipath: delegate flushing maps to multipathd multipath: add option to skip multipathd delegation libmultipath/config.h | 4 ++- libmultipath/configure.h | 3 -- libmultipath/devmapper.c | 63 +++++++++++++++++++++++++------------- libmultipath/devmapper.h | 8 ++++- libmultipath/structs_vec.c | 45 +++++++++++++++------------ multipath/main.c | 44 ++++++++++++++++++-------- multipath/multipath.8 | 4 +-- multipathd/cli.c | 1 + multipathd/cli_handlers.c | 19 ++++++++++++ multipathd/cli_handlers.h | 1 + multipathd/main.c | 50 +++++++++++++----------------- multipathd/main.h | 1 + 12 files changed, 155 insertions(+), 88 deletions(-) -- 2.17.2 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
