gfs2: perform quota checks against allocation parameters

Use struct gfs2_alloc_parms as an argument to gfs2_quota_check()
and gfs2_quota_lock_check() to check for quota violations while
accounting for the new blocks requested by the current operation
in ap->target.

Previously, the number of new blocks requested during an operation
were not accounted for during quota_check and would allow these
operations to exceed quota. This was not very apparent since most
operations allocated only 1 block at a time and quotas would get
violated in the next operation. i.e. quota excess would only be by
1 block or so. With fallocate, (where we allocate a bunch of blocks
at once) the quota excess is non-trivial and is addressed by this
patch.

Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/aops.c

@@ -671,12 +671,12 @@ static int gfs2_write_begin(struct file *file, struct address_space *mapping,
 
 	if (alloc_required) {
 		struct gfs2_alloc_parms ap = { .aflags = 0, };
-		error = gfs2_quota_lock_check(ip);
+		requested = data_blocks + ind_blocks;
+		ap.target = requested;
+		error = gfs2_quota_lock_check(ip, &ap);
 		if (error)
 			goto out_unlock;
 
-		requested = data_blocks + ind_blocks;
-		ap.target = requested;
 		error = gfs2_inplace_reserve(ip, &ap);
 		if (error)
 			goto out_qunlock;