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restripe: make sure zero buffer is always large enough. 

If restripe is called to restore stripes of one size and then
save stripes with a larger chunk size, the 'zero' buffer will not
be large enough and a double-degraded RAID6 will over-run the buffer.

So record the current size of the zero buffer and use it when deciding
if we need to allocate a new buffer.

Reported-by: Brad Campbell <lists2009@fnarfbargle.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2011-04-05 21:43:52 +10:00
parent 64385908bb
commit d47a29257a
1 changed files with 13 additions and 3 deletions
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16
restripe.c
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@ -334,6 +334,7 @@ void make_tables(void)
}
uint8_t *zero;
int zero_size;
/* Following was taken from linux/drivers/md/raid6recov.c */
/* Recover two failed data blocks. */
@ -490,9 +491,13 @@ int save_stripes(int *source, unsigned long long *offsets,
if (!tables_ready)
make_tables();
if (zero == NULL) {
if (zero == NULL || chunk_size > zero_size) {
if (zero)
free(zero);
zero = malloc(chunk_size);
memset(zero, 0, chunk_size);
if (zero)
memset(zero, 0, chunk_size);
zero_size = chunk_size;
}
len = data_disks * chunk_size;
@ -651,11 +656,16 @@ int restore_stripes(int *dest, unsigned long long *offsets,
if (posix_memalign((void**)&stripe_buf, 4096, raid_disks * chunk_size))
stripe_buf = NULL;
if (zero == NULL) {
if (zero == NULL || chunk_size > zero_size) {
if (zero)
free(zero);
zero = malloc(chunk_size);
if (zero)
memset(zero, 0, chunk_size);
zero_size = chunk_size;
}
if (stripe_buf == NULL || stripes == NULL || blocks == NULL
|| zero == NULL) {
free(stripe_buf);