btrfs-progs: remove variable length stack arrays

sparse hates variable length array definitions on the stack:

 btrfs-show-super.c:155:21: warning: Variable length array is used.

And it's right to.  They're a fragile construct that doesn't handle bad
input well at all.

Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/btrfs-show-super.c b/btrfs-show-super.c
index c2e844d..0c3c73c 100644 (file)
--- a/btrfs-show-super.c
+++ b/btrfs-show-super.c
@@ -152,7 +152,7 @@ static int load_and_dump_sb(char *filename, int fd, u64 sb_bytenr)
 
 static int check_csum_sblock(void *sb, int csum_size)
 {
-       char result[csum_size];
+       char result[BTRFS_CSUM_SIZE];
        u32 crc = ~(u32)0;
 
        crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE,

diff --git a/volumes.c b/volumes.c
index e460bce..dba5b0e 100644 (file)
--- a/volumes.c
+++ b/volumes.c
@@ -1779,12 +1779,15 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                             struct btrfs_multi_bio *multi,
                             u64 stripe_len, u64 *raid_map)
 {
-       struct extent_buffer *ebs[multi->num_stripes], *p_eb = NULL, *q_eb = NULL;
+       struct extent_buffer **ebs, *p_eb = NULL, *q_eb = NULL;
        int i;
        int j;
        int ret;
        int alloc_size = eb->len;
 
+       ebs = kmalloc(sizeof(*ebs) * multi->num_stripes, GFP_NOFS);
+       BUG_ON(!ebs);
+
        if (stripe_len > alloc_size)
                alloc_size = stripe_len;
 
@@ -1813,7 +1816,12 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                        q_eb = new_eb;
        }
        if (q_eb) {
-               void *pointers[multi->num_stripes];
+               void **pointers;
+
+               pointers = kmalloc(sizeof(*pointers) * multi->num_stripes,
+                                  GFP_NOFS);
+               BUG_ON(!pointers);
+
                ebs[multi->num_stripes - 2] = p_eb;
                ebs[multi->num_stripes - 1] = q_eb;
 
@@ -1821,6 +1829,7 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                        pointers[i] = ebs[i]->data;
 
                raid6_gen_syndrome(multi->num_stripes, stripe_len, pointers);
+               kfree(pointers);
        } else {
                ebs[multi->num_stripes - 1] = p_eb;
                memcpy(p_eb->data, ebs[0]->data, stripe_len);
@@ -1838,5 +1847,8 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                if (ebs[i] != eb)
                        kfree(ebs[i]);
        }
+
+       kfree(ebs);
+
        return 0;
 }