[dm-devel] [PATCH 3/6] multipath: centralize validation code
Martin Wilck
Martin.Wilck at suse.com
Fri May 15 20:37:16 UTC 2020
On Thu, 2020-05-14 at 20:59 -0500, Benjamin Marzinski wrote:
> This code pulls the multipath path validation code out of
> configure(),
> and puts it into its own function, check_path_valid(). This function
> calls a new libmultipath function, is_path_valid() to check just path
> requested. This seperation exists so that is_path_valid() can be
> reused
> by future code. This code will give almost the same answer as the
> existing code, with the exception that now, if a device is currently
> multipathed, it will always be a valid multipath path.
>
> Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
Great job getting the logic right! Readability massively improved.
Almost ack, a few comments and questions below.
Regards,
Martin
> ---
> libmultipath/Makefile | 2 +-
> libmultipath/devmapper.c | 49 +++++++
> libmultipath/devmapper.h | 1 +
> libmultipath/structs.h | 24 +---
> libmultipath/valid.c | 118 ++++++++++++++++
> libmultipath/valid.h | 32 +++++
> libmultipath/wwids.c | 10 +-
> multipath/main.c | 296 +++++++++++++++++------------------
> ----
> 8 files changed, 337 insertions(+), 195 deletions(-)
> create mode 100644 libmultipath/valid.c
> create mode 100644 libmultipath/valid.h
>
> diff --git a/libmultipath/Makefile b/libmultipath/Makefile
> index f19b7ad2..e5dac5ea 100644
> --- a/libmultipath/Makefile
> +++ b/libmultipath/Makefile
> @@ -48,7 +48,7 @@ OBJS = memory.o parser.o vector.o devmapper.o
> callout.o \
> log.o configure.o structs_vec.o sysfs.o prio.o checkers.o \
> lock.o file.o wwids.o prioritizers/alua_rtpg.o prkey.o \
> io_err_stat.o dm-generic.o generic.o foreign.o nvme-lib.o \
> - libsg.o
> + libsg.o valid.o
>
> all: $(LIBS)
>
> diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> index 7ed494a1..92f61133 100644
> --- a/libmultipath/devmapper.c
> +++ b/libmultipath/devmapper.c
> @@ -770,6 +770,55 @@ out:
> return r;
> }
>
> +/*
> + * Return
> + * 1 : map with uuid exists
> + * 0 : map with uuid doesn't exist
> + * -1 : error
> + */
> +int
> +dm_map_present_by_uuid(const char *uuid)
> +{
> + struct dm_task *dmt;
> + struct dm_info info;
> + char prefixed_uuid[WWID_SIZE + UUID_PREFIX_LEN];
> + int r = -1;
> +
> + if (!uuid || uuid[0] == '\0')
> + return 0;
> +
> + if (safe_sprintf(prefixed_uuid, UUID_PREFIX "%s", uuid))
> + goto out;
> +
> + if (!(dmt = dm_task_create(DM_DEVICE_INFO)))
> + goto out;
> +
> + dm_task_no_open_count(dmt);
> +
> + if (!dm_task_set_uuid(dmt, prefixed_uuid))
> + goto out_task;
> +
> + if (!dm_task_run(dmt))
> + goto out_task;
> +
> + if (!dm_task_get_info(dmt, &info))
> + goto out_task;
> +
> + r = 0;
> +
> + if (!info.exists)
> + goto out_task;
> +
> + r = 1;
I have nothing against goto for error handling, but here I'd prefer
r = !!info.exists;
> +out_task:
> + dm_task_destroy(dmt);
> +out:
> + if (r < 0)
> + condlog(3, "%s: dm command failed in %s: %s", uuid,
> + __FUNCTION__, strerror(errno));
> + return r;
> +}
> +
> static int
> dm_dev_t (const char * mapname, char * dev_t, int len)
> {
> diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
> index 17fc9faf..5ed7edc5 100644
> --- a/libmultipath/devmapper.h
> +++ b/libmultipath/devmapper.h
> @@ -39,6 +39,7 @@ int dm_simplecmd_noflush (int, const char *,
> uint16_t);
> int dm_addmap_create (struct multipath *mpp, char *params);
> int dm_addmap_reload (struct multipath *mpp, char *params, int
> flush);
> int dm_map_present (const char *);
> +int dm_map_present_by_uuid(const char *uuid);
> int dm_get_map(const char *, unsigned long long *, char *);
> int dm_get_status(const char *, char *);
> int dm_type(const char *, char *);
> diff --git a/libmultipath/structs.h b/libmultipath/structs.h
> index 9bd39eb1..d69bc2e9 100644
> --- a/libmultipath/structs.h
> +++ b/libmultipath/structs.h
> @@ -101,29 +101,13 @@ enum yes_no_undef_states {
> YNU_YES,
> };
>
> -#define _FIND_MULTIPATHS_F (1 << 1)
> -#define _FIND_MULTIPATHS_I (1 << 2)
> -#define _FIND_MULTIPATHS_N (1 << 3)
> -/*
> - * _FIND_MULTIPATHS_F must have the same value as YNU_YES.
> - * Generate a compile time error if that isn't the case.
> - */
> -extern char ___error1___[-(_FIND_MULTIPATHS_F != YNU_YES)];
> -
> -#define find_multipaths_on(conf) \
> - (!!((conf)->find_multipaths & _FIND_MULTIPATHS_F))
> -#define ignore_wwids_on(conf) \
> - (!!((conf)->find_multipaths & _FIND_MULTIPATHS_I))
> -#define ignore_new_devs_on(conf) \
> - (!!((conf)->find_multipaths & _FIND_MULTIPATHS_N))
> -
> enum find_multipaths_states {
> FIND_MULTIPATHS_UNDEF = YNU_UNDEF,
> FIND_MULTIPATHS_OFF = YNU_NO,
> - FIND_MULTIPATHS_ON = _FIND_MULTIPATHS_F,
> - FIND_MULTIPATHS_GREEDY = _FIND_MULTIPATHS_I,
> - FIND_MULTIPATHS_SMART = _FIND_MULTIPATHS_F|_FIND_MULTIPATHS_I,
> - FIND_MULTIPATHS_STRICT = _FIND_MULTIPATHS_F|_FIND_MULTIPATHS_N,
> + FIND_MULTIPATHS_ON = YNU_YES,
> + FIND_MULTIPATHS_GREEDY,
> + FIND_MULTIPATHS_SMART,
> + FIND_MULTIPATHS_STRICT,
> __FIND_MULTIPATHS_LAST,
> };
>
What was the reason you changed these definitions? AFAICS you've got
the logic right, and I'm not saying it shouldn't be done, but I'd like
to see a rationale. Is it just simplification / readability?
(Note to self: _FIND_MULTIPATHS_F etc. were introduced to make it
obvious at the time that these flags had the same effect as the
previous "ignore_wwids", "ignore_new_devs", and "find_multipaths"
command line options).
> diff --git a/libmultipath/valid.c b/libmultipath/valid.c
> new file mode 100644
> index 00000000..456b1f6e
> --- /dev/null
> +++ b/libmultipath/valid.c
> @@ -0,0 +1,118 @@
> +/*
> + Copyright (c) 2020 Benjamin Marzinski, IBM
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version 2
> + of the License, or (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <
> https://www.gnu.org/licenses/>;.
> + */
> +#include <stddef.h>
> +#include <errno.h>
> +#include <libudev.h>
> +
> +#include "vector.h"
> +#include "config.h"
> +#include "debug.h"
> +#include "util.h"
> +#include "devmapper.h"
> +#include "discovery.h"
> +#include "wwids.h"
> +#include "sysfs.h"
> +#include "blacklist.h"
> +#include "mpath_cmd.h"
> +#include "valid.h"
> +
> +int
> +is_path_valid(const char *name, struct config *conf, struct path
> *pp,
> + bool check_multipathd)
> +{
> + int r;
> + int fd;
> +
> + if (!pp || !name || !conf)
> + return PATH_IS_ERROR;
> +
> + if (conf->find_multipaths <= FIND_MULTIPATHS_UNDEF ||
> + conf->find_multipaths >= __FIND_MULTIPATHS_LAST)
> + return PATH_IS_ERROR;
> +
> + if (safe_sprintf(pp->dev, "%s", name))
> + return PATH_IS_ERROR;
> +
> + if (sysfs_is_multipathed(pp, true)) {
> + if (pp->wwid[0] == '\0')
> + return PATH_IS_ERROR;
> + return PATH_IS_VALID_NO_CHECK;
> + }
> +
> + /*
> + * "multipath -u" may be run before the daemon is started. In
> this
> + * case, systemd might own the socket but might delay
> multipathd
> + * startup until some other unit (udev settle!) has finished
> + * starting. With many LUNs, the listen backlog may be
> exceeded, which
> + * would cause connect() to block. This causes udev workers
> calling
> + * "multipath -u" to hang, and thus creates a deadlock, until
> "udev
> + * settle" times out. To avoid this, call connect() in non-
> blocking
> + * mode here, and take EAGAIN as indication for a filled-up
> systemd
> + * backlog.
> + */
> +
> + if (check_multipathd) {
> + fd = __mpath_connect(1);
> + if (fd < 0) {
> + if (errno != EAGAIN &&
> !systemd_service_enabled(name)) {
> + condlog(3, "multipathd not running or
> enabled");
> + return PATH_IS_NOT_VALID;
> + }
> + } else
> + mpath_disconnect(fd);
> + }
> +
> + pp->udev = udev_device_new_from_subsystem_sysname(udev,
> "block", name);
> + if (!pp->udev)
> + return PATH_IS_ERROR;
> +
> + r = pathinfo(pp, conf, DI_SYSFS | DI_WWID | DI_BLACKLIST);
> + if (r == PATHINFO_SKIPPED)
> + return PATH_IS_NOT_VALID;
> + else if (r)
> + return PATH_IS_ERROR;
> +
> + if (pp->wwid[0] == '\0')
> + return PATH_IS_NOT_VALID;
> +
> + if (pp->udev && pp->uid_attribute &&
> + filter_property(conf, pp->udev, 3, pp->uid_attribute) > 0)
> + return PATH_IS_NOT_VALID;
> +
> + r = is_failed_wwid(pp->wwid);
> + if (r != WWID_IS_NOT_FAILED) {
> + if (r == WWID_IS_FAILED)
> + return PATH_IS_NOT_VALID;
> + return PATH_IS_ERROR;
> + }
> +
> + if (conf->find_multipaths == FIND_MULTIPATHS_GREEDY)
> + return PATH_IS_VALID;
> +
> + if (check_wwids_file(pp->wwid, 0) == 0)
> + return PATH_IS_VALID_NO_CHECK;
> +
> + if (dm_map_present_by_uuid(pp->wwid) == 1)
> + return PATH_IS_VALID;
> +
> + /* all these act like FIND_MULTIPATHS_STRICT for finding if a
> + * path is valid */
> + if (conf->find_multipaths != FIND_MULTIPATHS_SMART)
> + return PATH_IS_NOT_VALID;
> +
> + return PATH_IS_MAYBE_VALID;
> +}
> diff --git a/libmultipath/valid.h b/libmultipath/valid.h
> new file mode 100644
> index 00000000..778658ad
> --- /dev/null
> +++ b/libmultipath/valid.h
> @@ -0,0 +1,32 @@
> +/*
> + Copyright (c) 2020 Benjamin Marzinski, IBM
> +
> + This program is free software; you can redistribute it and/or
> + modify it under the terms of the GNU General Public License
> + as published by the Free Software Foundation; either version 2
> + of the License, or (at your option) any later version.
> +
> + This program is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + GNU General Public License for more details.
> +
> + You should have received a copy of the GNU General Public License
> + along with this program. If not, see <
> https://www.gnu.org/licenses/>;.
> + */
> +#ifndef _VALID_H
> +#define _VALID_H
> +
> +enum is_path_valid_result {
> + PATH_IS_ERROR = -1,
> + PATH_IS_NOT_VALID,
> + PATH_IS_VALID,
> + PATH_IS_VALID_NO_CHECK,
I'd like to see the comment explaining the difference between VALID
and VALID_NO_CHECK here, too.
> + PATH_IS_MAYBE_VALID,
> + PATH_MAX_VALID_RESULT, /* only for bounds checking */
> +};
> +
> +int is_path_valid(const char *name, struct config *conf, struct path
> *pp,
> + bool check_multipathd);
> +
> +#endif /* _VALID_D */
> diff --git a/libmultipath/wwids.c b/libmultipath/wwids.c
> index 28a2150d..637cb0ab 100644
> --- a/libmultipath/wwids.c
> +++ b/libmultipath/wwids.c
> @@ -289,19 +289,19 @@ out:
> int
> should_multipath(struct path *pp1, vector pathvec, vector mpvec)
> {
> - int i, ignore_new_devs, find_multipaths;
> + int i, find_multipaths;
> struct path *pp2;
> struct config *conf;
>
> conf = get_multipath_config();
> - ignore_new_devs = ignore_new_devs_on(conf);
> - find_multipaths = find_multipaths_on(conf);
> + find_multipaths = conf->find_multipaths;
> put_multipath_config(conf);
> - if (!find_multipaths && !ignore_new_devs)
> + if (find_multipaths == FIND_MULTIPATHS_OFF ||
> + find_multipaths == FIND_MULTIPATHS_GREEDY)
> return 1;
>
> condlog(4, "checking if %s should be multipathed", pp1->dev);
> - if (!ignore_new_devs) {
> + if (find_multipaths != FIND_MULTIPATHS_STRICT) {
> char tmp_wwid[WWID_SIZE];
> struct multipath *mp = find_mp_by_wwid(mpvec, pp1-
> >wwid);
Noting explicitly here: you got the complex logic right. Kudos :-)
>
> diff --git a/multipath/main.c b/multipath/main.c
> index 545ead87..953fab27 100644
> --- a/multipath/main.c
> +++ b/multipath/main.c
> @@ -63,21 +63,18 @@
> #include "propsel.h"
> #include "time-util.h"
> #include "file.h"
> +#include "valid.h"
>
> int logsink;
> struct udev *udev;
> struct config *multipath_conf;
>
> /*
> - * Return values of configure(), print_cmd_valid(), and main().
> - * RTVL_{YES,NO} are synonyms for RTVL_{OK,FAIL} for the
> CMD_VALID_PATH case.
> + * Return values of configure(), check_path_valid(), and main().
> */
> enum {
> RTVL_OK = 0,
> - RTVL_YES = RTVL_OK,
> RTVL_FAIL = 1,
> - RTVL_NO = RTVL_FAIL,
> - RTVL_MAYBE, /* only used internally, never returned */
> RTVL_RETRY, /* returned by configure(), not by main() */
> };
>
> @@ -269,9 +266,6 @@ get_dm_mpvec (enum mpath_cmds cmd, vector curmp,
> vector pathvec, char * refwwid)
> continue;
> }
>
> - if (cmd == CMD_VALID_PATH)
> - continue;
> -
> dm_get_map(mpp->alias, &mpp->size, params);
> condlog(3, "params = %s", params);
> dm_get_status(mpp->alias, status);
> @@ -491,10 +485,11 @@ static int print_cmd_valid(int k, const vector
> pathvec,
> struct timespec until;
> struct path *pp;
>
> - if (k != RTVL_YES && k != RTVL_NO && k != RTVL_MAYBE)
> - return RTVL_NO;
> + if (k != PATH_IS_VALID && k != PATH_IS_NOT_VALID &&
> + k != PATH_IS_MAYBE_VALID)
> + return PATH_IS_NOT_VALID;
>
> - if (k == RTVL_MAYBE) {
> + if (k == PATH_IS_MAYBE_VALID) {
> /*
> * Caller ensures that pathvec[0] is the path to
> * examine.
> @@ -504,7 +499,7 @@ static int print_cmd_valid(int k, const vector
> pathvec,
> wait = find_multipaths_check_timeout(
> pp, pp->find_multipaths_timeout, &until);
> if (wait != FIND_MULTIPATHS_WAITING)
> - k = RTVL_NO;
> + k = PATH_IS_NOT_VALID;
> } else if (pathvec != NULL && (pp = VECTOR_SLOT(pathvec, 0)))
> wait = find_multipaths_check_timeout(pp, 0, &until);
> if (wait == FIND_MULTIPATHS_WAITING)
> @@ -513,9 +508,9 @@ static int print_cmd_valid(int k, const vector
> pathvec,
> else if (wait == FIND_MULTIPATHS_WAIT_DONE)
> printf("FIND_MULTIPATHS_WAIT_UNTIL=\"0\"\n");
> printf("DM_MULTIPATH_DEVICE_PATH=\"%d\"\n",
> - k == RTVL_MAYBE ? 2 : k == RTVL_YES ? 1 : 0);
> + k == PATH_IS_MAYBE_VALID ? 2 : k == PATH_IS_VALID ? 1 :
> 0);
> /* Never return RTVL_MAYBE */
> - return k == RTVL_NO ? RTVL_NO : RTVL_YES;
> + return k == PATH_IS_NOT_VALID ? PATH_IS_NOT_VALID :
> PATH_IS_VALID;
> }
>
> /*
> @@ -548,7 +543,6 @@ configure (struct config *conf, enum mpath_cmds
> cmd,
> int di_flag = 0;
> char * refwwid = NULL;
> char * dev = NULL;
> - bool released = released_to_systemd();
>
> /*
> * allocate core vectors to store paths and multipaths
> @@ -573,7 +567,7 @@ configure (struct config *conf, enum mpath_cmds
> cmd,
> cmd != CMD_REMOVE_WWID &&
> (filter_devnode(conf->blist_devnode,
> conf->elist_devnode, dev) > 0)) {
> - goto print_valid;
> + goto out;
> }
>
> /*
> @@ -581,14 +575,10 @@ configure (struct config *conf, enum mpath_cmds
> cmd,
> * failing the translation is fatal (by policy)
> */
> if (devpath) {
> - int failed = get_refwwid(cmd, devpath, dev_type,
> - pathvec, &refwwid);
> + get_refwwid(cmd, devpath, dev_type, pathvec, &refwwid);
> if (!refwwid) {
> condlog(4, "%s: failed to get wwid", devpath);
> - if (failed == 2 && cmd == CMD_VALID_PATH)
> - goto print_valid;
> - else
> - condlog(3, "scope is null");
> + condlog(3, "scope is null");
> goto out;
> }
> if (cmd == CMD_REMOVE_WWID) {
> @@ -614,53 +604,6 @@ configure (struct config *conf, enum mpath_cmds
> cmd,
> goto out;
> }
> condlog(3, "scope limited to %s", refwwid);
> - /* If you are ignoring the wwids file and
> find_multipaths is
> - * set, you need to actually check if there are two
> available
> - * paths to determine if this path should be
> multipathed. To
> - * do this, we put off the check until after
> discovering all
> - * the paths.
> - * Paths listed in the wwids file are always considered
> valid.
> - */
> - if (cmd == CMD_VALID_PATH) {
> - if (is_failed_wwid(refwwid) == WWID_IS_FAILED)
> {
> - r = RTVL_NO;
> - goto print_valid;
> - }
> - if ((!find_multipaths_on(conf) &&
> - ignore_wwids_on(conf)) ||
> - check_wwids_file(refwwid, 0) == 0)
> - r = RTVL_YES;
> - if (!ignore_wwids_on(conf))
> - goto print_valid;PATH_IS_VALID_NO_CHECK
>
> - /* At this point, either r==0 or
> find_multipaths_on. */
> -
> - /*
> - * Shortcut for find_multipaths smart:
> - * Quick check if path is already multipathed.
> - */
> - if (sysfs_is_multipathed(VECTOR_SLOT(pathvec,
> 0),
> - false)) {
> - r = RTVL_YES;
> - goto print_valid;
> - }
> -
> - /*
> - * DM_MULTIPATH_DEVICE_PATH=="0" means that we
> have
> - * been called for this device already, and
> have
> - * released it to systemd. Unless the device is
> now
> - * already multipathed (see above), we can't
> try to
> - * grab it, because setting SYSTEMD_READY=0
> would
> - * cause file systems to be unmounted.
> - * Leave DM_MULTIPATH_DEVICE_PATH="0".
> - */
> - if (released) {
> - r = RTVL_NO;
> - goto print_valid;
> - }
> - if (r == RTVL_YES)
> - goto print_valid;
> - /* find_multipaths_on: Fall through to path
> detection */
> - }
> }
>
> /*
> @@ -701,59 +644,6 @@ configure (struct config *conf, enum mpath_cmds
> cmd,
> goto out;
> }
>
> - if (cmd == CMD_VALID_PATH) {
> - struct path *pp;
> - int fd;
> -
> - /* This only happens if find_multipaths and
> - * ignore_wwids is set, and the path is not in WWIDs
> - * file, not currently multipathed, and has
> - * never been released to systemd.
> - * If there is currently a multipath device matching
> - * the refwwid, or there is more than one path matching
> - * the refwwid, then the path is valid */
> - if (VECTOR_SIZE(curmp) != 0) {
> - r = RTVL_YES;
> - goto print_valid;
> - } else if (VECTOR_SIZE(pathvec) > 1)
> - r = RTVL_YES;
> - else
> - r = RTVL_MAYBE;
> -
> - /*
> - * If opening the path with O_EXCL fails, the path
> - * is in use (e.g. mounted during initramfs
> processing).
> - * We know that it's not used by dm-multipath.
> - * We may not set SYSTEMD_READY=0 on such devices, it
> - * might cause systemd to umount the device.
> - * Use O_RDONLY, because udevd would trigger another
> - * uevent for close-after-write.
> - *
> - * The O_EXCL check is potentially dangerous, because
> it may
> - * race with other tasks trying to access the device.
> Therefore
> - * this code is only executed if the path hasn't been
> released
> - * to systemd earlier (see above).
> - *
> - * get_refwwid() above stores the path we examine in
> slot 0.
> - */
> - pp = VECTOR_SLOT(pathvec, 0);
> - fd = open(udev_device_get_devnode(pp->udev),
> - O_RDONLY|O_EXCL);
> - if (fd >= 0)
> - close(fd);
> - else {
> - condlog(3, "%s: path %s is in use: %s",
> - __func__, pp->dev,
> - strerror(errno));
> - /*
> - * Check if we raced with multipathd
> - */
> - r = sysfs_is_multipathed(VECTOR_SLOT(pathvec,
> 0),
> - false) ? RTVL_YES :
> RTVL_NO;
> - }
> - goto print_valid;
> - }
> -
> if (cmd != CMD_CREATE && cmd != CMD_DRY_RUN) {
> r = RTVL_OK;
> goto out;
> @@ -766,10 +656,6 @@ configure (struct config *conf, enum mpath_cmds
> cmd,
> conf->force_reload, cmd);
> r = rc == CP_RETRY ? RTVL_RETRY : rc == CP_OK ? RTVL_OK :
> RTVL_FAIL;
>
> -print_valid:
> - if (cmd == CMD_VALID_PATH)
> - r = print_cmd_valid(r, pathvec, conf);
> -
> out:
> if (refwwid)
> FREE(refwwid);
> @@ -780,6 +666,112 @@ out:
> return r;
> }
>
> +static int
> +check_path_valid(const char *name, struct config *conf, bool
> is_uevent)
> +{
> + int fd, r = PATH_IS_ERROR;
> + struct path *pp = NULL;
> + vector pathvec = NULL;
> +
> + pp = alloc_path();
> + if (!pp)
> + return RTVL_FAIL;
> +
> + r = is_path_valid(name, conf, pp, is_uevent);
> + if (r <= PATH_IS_ERROR || r >= PATH_MAX_VALID_RESULT)
> + goto fail;
> +
About the following block ...
> + /* set path values if is_path_valid() didn't */
> + if (!pp->udev)
> + pp->udev = udev_device_new_from_subsystem_sysname(udev,
> "block",
> + name)
> ;
> + if (!pp->udev)
> + goto fail;
> +
> + if (!strlen(pp->dev_t)) {
> + dev_t devt = udev_device_get_devnum(pp->udev);
> + if (major(devt) == 0 && minor(devt) == 0)
> + goto fail;
> + snprintf(pp->dev_t, BLK_DEV_SIZE, "%d:%d", major(devt),
> + minor(devt));
> + }
> +
> + pathvec = vector_alloc();
> + if (!pathvec)
> + goto fail;
> +
> + if (store_path(pathvec, pp) != 0) {
> + free_path(pp);
> + goto fail;
> + }
... why do you do this here, rather than after the (r !=
PATH_IS_MAYBE_VALID) clause below? AFAICS you don't need pathvec until
you run path_discovery().
> +
> + if ((r == PATH_IS_VALID || r == PATH_IS_MAYBE_VALID) &&
> + released_to_systemd())
> + r = PATH_IS_NOT_VALID;
> +
> + /* This state is only used to skip the released_to_systemd()
> check */
> + if (r == PATH_IS_VALID_NO_CHECK)
> + r = PATH_IS_VALID;
> +
> + if (r != PATH_IS_MAYBE_VALID)
> + goto out;
> +
> + /*
> + * If opening the path with O_EXCL fails, the path
> + * is in use (e.g. mounted during initramfs processing).
> + * We know that it's not used by dm-multipath.
> + * We may not set SYSTEMD_READY=0 on such devices, it
> + * might cause systemd to umount the device.
> + * Use O_RDONLY, because udevd would trigger another
> + * uevent for close-after-write.
> + *
> + * The O_EXCL check is potentially dangerous, because it may
> + * race with other tasks trying to access the device. Therefore
> + * this code is only executed if the path hasn't been released
> + * to systemd earlier (see above).
> + */
> + fd = open(udev_device_get_devnode(pp->udev), O_RDONLY|O_EXCL);
> + if (fd >= 0)
> + close(fd);
> + else {
> + condlog(3, "%s: path %s is in use: %m", __func__, pp-
> >dev);
> + /* Check if we raced with multipathd */
> + if (sysfs_is_multipathed(pp, false))
> + r = PATH_IS_VALID;
> + else
> + r = PATH_IS_NOT_VALID;
> + goto out;
> + }
> +
> + /* For find_multipaths = SMART, if there is more than one path
> + * matching the refwwid, then the path is valid */
> + if (path_discovery(pathvec, DI_SYSFS | DI_WWID) < 0)
> + goto fail;
> + filter_pathvec(pathvec, pp->wwid);
> + if (VECTOR_SIZE(pathvec) > 1)
> + r = PATH_IS_VALID;
> + else
> + r = PATH_IS_MAYBE_VALID;
> +
> +out:
> + r = print_cmd_valid(r, pathvec, conf);
> + free_pathvec(pathvec, FREE_PATHS);
> + /*
> + * multipath -u must exit with status 0, otherwise udev won't
> + * import its output.
> + */
> + if (!is_uevent && r == PATH_IS_NOT_VALID)
> + return RTVL_FAIL;
> + return RTVL_OK;
> +
> +fail:
> + if (pathvec)
> + free_pathvec(pathvec, FREE_PATHS);
> + else
> + free_path(pp);
> + return RTVL_FAIL;
> +}
> +
> static int
> get_dev_type(char *dev) {
> struct stat buf;
> @@ -861,32 +853,6 @@ out:
> return r;
> }
>
> -static int test_multipathd_socket(void)
> -{
> - int fd;
> - /*
> - * "multipath -u" may be run before the daemon is started. In
> this
> - * case, systemd might own the socket but might delay
> multipathd
> - * startup until some other unit (udev settle!) has finished
> - * starting. With many LUNs, the listen backlog may be
> exceeded, which
> - * would cause connect() to block. This causes udev workers
> calling
> - * "multipath -u" to hang, and thus creates a deadlock, until
> "udev
> - * settle" times out. To avoid this, call connect() in non-
> blocking
> - * mode here, and take EAGAIN as indication for a filled-up
> systemd
> - * backlog.
> - */
> -
> - fd = __mpath_connect(1);
> - if (fd == -1) {
> - if (errno == EAGAIN)
> - condlog(3, "daemon backlog exceeded");
> - else
> - return 0;
> - } else
> - close(fd);
> - return 1;
> -}
> -
> int
> main (int argc, char *argv[])
> {
> @@ -970,7 +936,11 @@ main (int argc, char *argv[])
> conf->force_reload = FORCE_RELOAD_YES;
> break;
> case 'i':
> - conf->find_multipaths |= _FIND_MULTIPATHS_I;
> + if (conf->find_multipaths == FIND_MULTIPATHS_ON
> ||
> + conf->find_multipaths ==
> FIND_MULTIPATHS_STRICT)
> + conf->find_multipaths =
> FIND_MULTIPATHS_SMART;
> + else if (conf->find_multipaths ==
> FIND_MULTIPATHS_OFF)
> + conf->find_multipaths =
> FIND_MULTIPATHS_GREEDY;
Ok. Previously FIND_MULTIPATHS_SMART was not the same value as
FIND_MULTIPATHS_STRICT + _FIND_MULTIPATHS_I. Effectively, this doesn't
change logic, but only because the check for ignore_new_devs_on() in
should_multipath() is actually redundant. (IIRC in the past we'd
determined that "strict" + "ignore_wwids" makes no sense).
> break;
> case 't':
> r = dump_config(conf, NULL, NULL) ? RTVL_FAIL :
> RTVL_OK;
> @@ -1064,15 +1034,10 @@ main (int argc, char *argv[])
> condlog(0, "the -c option requires a path to check");
> goto out;
> }
> - if (cmd == CMD_VALID_PATH &&
> - dev_type == DEV_UEVENT) {
> - if (!test_multipathd_socket()) {
> - condlog(3, "%s: daemon is not running", dev);
> - if (!systemd_service_enabled(dev)) {
> - r = print_cmd_valid(RTVL_NO, NULL,
> conf);
> - goto out;
> - }
> - }
> + if (cmd == CMD_VALID_PATH) {
> + char * name = convert_dev(dev, (dev_type ==
> DEV_DEVNODE));
> + r = check_path_valid(name, conf, dev_type ==
> DEV_UEVENT);
> + goto out;
> }
>
> if (cmd == CMD_REMOVE_WWID && !dev) {
> @@ -1136,13 +1101,6 @@ out:
> cleanup_prio();
> cleanup_checkers();
>
> - /*
> - * multipath -u must exit with status 0, otherwise udev won't
> - * import its output.
> - */
> - if (cmd == CMD_VALID_PATH && dev_type == DEV_UEVENT && r ==
> RTVL_NO)
> - r = RTVL_OK;
> -
> if (dev_type == DEV_UEVENT)
> closelog();
>
--
Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
SUSE Software Solutions Germany GmbH
HRB 36809, AG Nürnberg GF: Felix
Imendörffer
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