shithub: gefs

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dump: don't take lock when dumping snaps

if we have a crashed proc while updating snaps, it's
likely to hold the mount lock, so acquiring the mount
lock means we deadlock in 'show snap', depriving us of
a useful debug tool, in exchange for some not so useful
informatin that we can grab from acid painlessly.

--- a/dump.c

+++ b/dump.c

@@ -376,7 +376,6 @@

 showsnap(int fd, char **ap, int na)

 {

 	char *e, pfx[Snapsz];

-	Mount *mnt;

 	vlong id;

 	Scan s;

 	uint flg;

@@ -385,13 +384,6 @@

 	/* dump the labels */

 	if(na == 0){

-		lock(&fs->mountlk);

-		fprint(fd, "open:");

-		for(mnt = fs->mounts; mnt != nil; mnt = mnt->next)

-			fprint(fd, " %s\n", mnt->name);

-		fprint(fd, "\n");

-		unlock(&fs->mountlk);

-

 		pfx[0] = Klabel;

 		sz = 1;

 		btnewscan(&s, pfx, sz);