sanchayanmaity/minix
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity

VFS: more three-level-lock sanity checking

Browse source
This commit is contained in:
Thomas Veerman 2012-04-11 09:13:49 +00:00
parent ca7a466f48
commit e292ba487e
1 changed files with 7 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
servers/vfs/tll.c
View file

@ -48,7 +48,8 @@ static int tll_append(tll_t *tllp, tll_access_t locktype)
if (tllp->t_current == TLL_READ) {
tllp->t_readonly++;
tllp->t_owner = NULL;
}
} else if (tllp->t_current == TLL_WRITE)
assert(tllp->t_readonly == 0);
/* Due to the way upgrading and downgrading works, read-only requests are
* scheduled to run after a downgraded lock is released (because they are
@ -164,6 +165,8 @@ int tll_lock(tll_t *tllp, tll_access_t locktype)
else { /* Record owner if locktype is read-serialized or write-only */
tllp->t_owner = self;
}
if (tllp->t_current == TLL_WRITE)
assert(tllp->t_readonly == 0);
return(OK);
}
@ -240,6 +243,9 @@ int tll_unlock(tll_t *tllp)
signal_owner = 1;
}
if (tllp->t_owner == self && tllp->t_current == TLL_WRITE)
assert(tllp->t_readonly == 0);
if(tllp->t_owner == self || (tllp->t_owner == NULL && tllp->t_readonly == 0)){
/* Let another read-serialized or write-only request obtain access.
* Write-only has priority, but only after the last read-only access