ext4: fix clang build regression (b80b32b6) · Commits · 戴 / test

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: ("ext4: fix warning about stack corruption") Reported-by:

Stefan Agner <stefan@agner.ch> Tested-by:

Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Signed-off-by:

Theodore Ts'o <tytso@mit.edu>

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);

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