Re: [PATCH 2/3] imsm: FIX: 'UT 09imsm-assemble' fails

[NeilBrown <neilb@suse.de>]

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On Wed, 14 Dec 2011 16:07:12 +0100 Adam Kwolek <adam.kwolek@intel.com> wrote:

> Problem was introduced by patch (2011-06-08):
>    getinfo_super now clears the 'info' structure before filling it in.
> 
> Field update private is not managed here and pointer associated outside
> is cleaned up.
> Add code for field update_private cleaning preservation.
> In places where in patch
>   'getinfo_super now clears the 'info' structure before filling it in.'
> cleaning structure was removed, cleaning update_private field was added
> as getinfo_super() cannot be responsible for this pointer management.
> 
> Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
> ---
> 
>  Assemble.c    |    2 ++
>  Incremental.c |    3 +++
>  super-intel.c |    9 +++++++++
>  3 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/Assemble.c b/Assemble.c
> index fac2bad..c8b538f 100644
> --- a/Assemble.c
> +++ b/Assemble.c
> @@ -422,6 +422,7 @@ int Assemble(struct supertype *st, char *mddev,
>  					int uuid[4];
>  
>  					content = &info;
> +					info.update_private = NULL
>  					tst->ss->getinfo_super(tst, content, NULL);
>  
>  					if (!parse_uuid(ident->container, uuid) ||
> @@ -485,6 +486,7 @@ int Assemble(struct supertype *st, char *mddev,
>  		} else {
>  
>  			content = &info;
> +			info.update_private = NULL
>  			tst->ss->getinfo_super(tst, content, NULL);
>  
>  			if (!ident_matches(ident, content, tst,
> diff --git a/Incremental.c b/Incremental.c
> index d3724a4..112a1ec 100644
> --- a/Incremental.c
> +++ b/Incremental.c
> @@ -205,6 +205,7 @@ int Incremental(char *devname, int verbose, int runstop,
>  	}
>  	close (dfd); dfd = -1;
>  
> +	info.update_private = NULL
>  	st->ss->getinfo_super(st, &info, NULL);
>  
>  	/* 3/ Check if there is a match in mdadm.conf */
> @@ -404,6 +405,7 @@ int Incremental(char *devname, int verbose, int runstop,
>  				goto out_unlock;
>  			}
>  			close(dfd2);
> +			info.update_private = NULL
>  			st2->ss->getinfo_super(st2, &info2, NULL);
>  			st2->ss->free_super(st2);
>  			if (info.array.level != info2.array.level ||
> @@ -1382,6 +1384,7 @@ static int Incremental_container(struct supertype *st, char *devname,
>  	int ra_blocked = 0;
>  	int ra_all = 0;
>  
> +	info.update_private = NULL
>  	st->ss->getinfo_super(st, &info, NULL);
>  
>  	if ((runstop > 0 && info.container_enough >= 0) ||
> diff --git a/super-intel.c b/super-intel.c
> index e1073ef..5e1d278 100644
> --- a/super-intel.c
> +++ b/super-intel.c
> @@ -2365,8 +2365,13 @@ static void getinfo_super_imsm_volume(struct supertype *st, struct mdinfo *info,
>  	char *devname;
>  	unsigned int component_size_alligment;
>  	int map_disks = info->array.raid_disks;
> +	void *update_private_saver = info->update_private;
>  
>  	memset(info, 0, sizeof(*info));
> +	/* preserve pointer cleanup, as someone elese is pointer owner
> +	 */
> +	info->update_private = update_private_saver;
> +
>  	if (prev_map)
>  		map_to_analyse = prev_map;
>  
> @@ -2601,12 +2606,16 @@ static void getinfo_super_imsm(struct supertype *st, struct mdinfo *info, char *
>  	int max_enough = -1;
>  	int i;
>  	struct imsm_super *mpb;
> +	void *update_private_saver = info->update_private;
>  
>  	if (super->current_vol >= 0) {
>  		getinfo_super_imsm_volume(st, info, map);
>  		return;
>  	}
>  	memset(info, 0, sizeof(*info));
> +	/* preserve pointer cleanup, as someone elese is pointer owner
> +	 */
> +	info->update_private = update_private_saver;
>  
>  	/* Set raid_disks to zero so that Assemble will always pull in valid
>  	 * spares
> 

You didn't really think I'd let that through, did you :-)

I've written an alternate which gets rid of update_private.

Could you and Dan please review and check it performs as required.

Thanks,
NeilBrown


commit 8606be19835abaf888d0fbd1729dcda82a8b2815
Author: NeilBrown <neilb@suse.de>
Date:   Thu Dec 15 14:59:12 2011 +1100

    Remove update_private
    
    This fields doesn't work any more as ->getinfo_super clears the info
    structure at an awkward time.  So get rid of it and do it differently.
    
    The issue is that the metadata handler cannot tell if the uuid it has
    was randomly generated or explicitly requested, except on the first
    call.
    And we don't want to accept explicit requests for IMSM.
    So when it was auto-generated, make it look distinctive by having the
    same int copied in all 4 positions.  If someone requests a uuid like
    that, I guess they get away with it.
    
    Reported-by: Adam Kwolek <adam.kwolek@intel.com>
    Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/Assemble.c b/Assemble.c
index fac2bad..74fb6a3 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -706,7 +706,6 @@ int Assemble(struct supertype *st, char *mddev,
 	bitmap_done = 0;
 #endif
 	/* Ok, no bad inconsistancy, we can try updating etc */
-	content->update_private = NULL;
 	devices = malloc(num_devs * sizeof(*devices));
 	devmap = calloc(num_devs * content->array.raid_disks, 1);
 	for (tmpdev = devlist; tmpdev; tmpdev=tmpdev->next) if (tmpdev->used == 1) {
@@ -891,8 +890,6 @@ int Assemble(struct supertype *st, char *mddev,
 		}
 		devcnt++;
 	}
-	free(content->update_private);
-	content->update_private = NULL;
 
 	if (devcnt == 0) {
 		fprintf(stderr, Name ": no devices found for %s\n",
diff --git a/mdadm.h b/mdadm.h
index 1351d42..4f3533f 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -217,11 +217,6 @@ struct mdinfo {
 	unsigned long		cache_size; /* size of raid456 stripe cache*/
 	int			mismatch_cnt;
 	char			text_version[50];
-	void 			*update_private; /* for passing metadata-format
-						  * specific update data
-						  * between successive calls to
-						  * update_super()
-						  */
 
 	int container_member; /* for assembling external-metatdata arrays
 			       * This is to be used internally by metadata
diff --git a/super-intel.c b/super-intel.c
index e1073ef..78781c7 100644
--- a/super-intel.c
+++ b/super-intel.c
@@ -2791,25 +2791,30 @@ static int update_super_imsm(struct supertype *st, struct mdinfo *info,
 
 	mpb = super->anchor;
 
-	if (strcmp(update, "uuid") == 0 && uuid_set && !info->update_private)
-		rv = -1;
-	else if (strcmp(update, "uuid") == 0 && uuid_set && info->update_private) {
-		mpb->orig_family_num = *((__u32 *) info->update_private);
-		rv = 0;
-	} else if (strcmp(update, "uuid") == 0) {
-		__u32 *new_family = malloc(sizeof(*new_family));
-
-		/* update orig_family_number with the incoming random
-		 * data, report the new effective uuid, and store the
-		 * new orig_family_num for future updates.
+	if (strcmp(update, "uuid") == 0) {
+		/* We take this to mean that the family_num should be updated.
+		 * However that is much smaller than the uuid so we cannot really
+		 * allow an explicit uuid to be given.  And it is hard to reliably
+		 * know if one was.
+		 * So if !uuid_set we know the current uuid is random and just used
+		 * the first 'int' and copy it to the other 3 positions.
+		 * Otherwise we require the 4 'int's to be the same as would be the
+		 * case if we are using a random uuid.  So an explicit uuid will be
+		 * accepted as long as all for ints are the same... which shouldn't hurt
 		 */
-		if (new_family) {
-			memcpy(&mpb->orig_family_num, info->uuid, sizeof(__u32));
-			uuid_from_super_imsm(st, info->uuid);
-			*new_family = mpb->orig_family_num;
-			info->update_private = new_family;
+		if (uuid_set) {
+			info->uuid[1] = info->uuid[2] = info->uuid[3] = info->uuid[0];
 			rv = 0;
+		} else {
+			if (info->uuid[0] != info->uuid[1] ||
+			    info->uuid[1] != info->uuid[2] ||
+			    info->uuid[2] != info->uuid[3])
+				rv = -1;
+			else
+				rv = 0;
 		}
+		if (rv == 0)
+			mpb->orig_family_num = info->uuid[0];
 	} else if (strcmp(update, "assemble") == 0)
 		rv = 0;
 	else

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