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Commit b80b32b6 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: fix clang build regression 



Arnd Bergmann <arnd@arndb.de>

As Stefan pointed out, I misremembered what clang can do specifically,
and it turns out that the variable-length array at the end of the
structure did not work (a flexible array would have worked here
but not solved the problem):

fs/ext4/mballoc.c:2303:17: error: fields must have a constant size:
'variable length array in structure' extension will never be supported
                ext4_grpblk_t counters[blocksize_bits + 2];

This reverts part of my previous patch, using a fixed-size array
again, but keeping the check for the array overflow.

Fixes: 2df2c340 ("ext4: fix warning about stack corruption")
Reported-by: default avatarStefan Agner <stefan@agner.ch>
Tested-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent aae4e7a8

fs/ext4/mballoc.c

+5 −2
Original line number Diff line number Diff line
@@ -2300,7 +2300,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) 
					     EXT4_MAX_BLOCK_LOG_SIZE);

	struct sg {

		struct ext4_group_info info;

		ext4_grpblk_t counters[blocksize_bits + 2];

		ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];

	} sg;



	group--;
@@ -2309,6 +2309,9 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) 
			      " 2^0   2^1   2^2   2^3   2^4   2^5   2^6  "

			      " 2^7   2^8   2^9   2^10  2^11  2^12  2^13  ]\n");



	i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +

		sizeof(struct ext4_group_info);



	grinfo = ext4_get_group_info(sb, group);

	/* Load the group info in memory only if not already loaded. */

	if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
@@ -2320,7 +2323,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) 
		buddy_loaded = 1;

	}



	memcpy(&sg, ext4_get_group_info(sb, group), sizeof(sg));

	memcpy(&sg, ext4_get_group_info(sb, group), i);



	if (buddy_loaded)

		ext4_mb_unload_buddy(&e4b);