fs/hfs/extent.c: fix array out of bounds read of array extent

Currently extent and index i are both being incremented causing an array
out of bounds read on extent[i]. Fix this by removing the extraneous
increment of extent.

Ernesto said:

: This is only triggered when deleting a file with a resource fork. I
: may be wrong because the documentation isn't clear, but I don't think
: you can create those under linux. So I guess nobody was testing them.
:
: > A disk space leak, perhaps?
:
: That's what it looks like in general. hfs_free_extents() won't do
: anything if the block count doesn't add up, and the error will be
: ignored. Now, if the block count randomly does add up, we could see
: some corruption.

Detected by CoverityScan, CID#711541 ("Out of bounds read")

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Colin Ian King <[e-mail]>
Reviewed-by: Ernesto A. Fernndez <[e-mail]>
Cc: David Howells <[e-mail]>
Cc: Al Viro <[e-mail]>
Cc: Hin-Tak Leung <[e-mail]>
Cc: Vyacheslav Dubeyko <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/hfs/extent.c

···
 		return 0;
 
 	blocks = 0;
-	for (i = 0; i < 3; extent++, i++)
+	for (i = 0; i < 3; i++)
 		blocks += be16_to_cpu(extent[i].count);
 
 	res = hfs_free_extents(sb, extent, blocks, blocks);