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Commit a3c75e3e authored by Sami Tolvanen's avatar Sami Tolvanen
Browse files

Zero blocks before BLKDISCARD 

Due to observed BLKDISCARD flakiness, overwrite blocks that we want
to discard with zeros first to avoid later issues with dm-verity if
BLKDISCARD is not successful.

Bug: 20614277
Bug: 20881595
Change-Id: I4f6f2db39db990879ff10468c9db41606497bd6f
parent e6f6097a

updater/blockimg.c

+17 −1
Original line number Diff line number Diff line
@@ -1465,6 +1465,7 @@ pcdout: 
static int PerformCommandErase(CommandParameters* params) {

    char* range = NULL;

    int i;

    int j;

    int rc = -1;

    RangeSet* tgt = NULL;

    struct stat st;
@@ -1491,7 +1492,7 @@ static int PerformCommandErase(CommandParameters* params) { 
    range = strtok_r(NULL, " ", &params->cpos);



    if (range == NULL) {

        fprintf(stderr, "missing target blocks for zero\n");

        fprintf(stderr, "missing target blocks for erase\n");

        goto pceout;

    }
@@ -1500,7 +1501,22 @@ static int PerformCommandErase(CommandParameters* params) { 
    if (params->canwrite) {

        fprintf(stderr, " erasing %d blocks\n", tgt->size);



        allocate(BLOCKSIZE, &params->buffer, &params->bufsize);

        memset(params->buffer, 0, BLOCKSIZE);



        for (i = 0; i < tgt->count; ++i) {

            // Always zero the blocks first to work around possibly flaky BLKDISCARD

            // Bug: 20881595

            if (!check_lseek(params->fd, (off64_t) tgt->pos[i * 2] * BLOCKSIZE, SEEK_SET)) {

                goto pceout;

            }



            for (j = tgt->pos[i * 2]; j < tgt->pos[i * 2 + 1]; ++j) {

                if (write_all(params->fd, params->buffer, BLOCKSIZE) == -1) {

                    goto pceout;

                }

            }



            // offset in bytes

            blocks[0] = tgt->pos[i * 2] * (uint64_t) BLOCKSIZE;

            // length in bytes