Function Ext2ZeroBuffer

Ext4Fsd/ext3/generic.c:811–879

BOOLEAN
Ext2ZeroBuffer( IN PEXT2_IRP_CONTEXT    IrpContext,
                IN PEXT2_VCB            Vcb,
                IN LONGLONG             offset,
                IN ULONG                size
    )
{
    struct buffer_head *bh = NULL;
    BOOLEAN             rc = 0;

    __try {

        while (size) {

            sector_t    block;
            ULONG       len = 0, delta = 0;

            block = (sector_t) (offset >> BLOCK_BITS);
            delta = (ULONG)offset & (BLOCK_SIZE - 1);
            len = BLOCK_SIZE - delta;
            if (size < len)
                len = size;

            if (delta == 0 && len >= BLOCK_SIZE) {
                bh = sb_getblk_zero(&Vcb->sb, block);
            } else {
                bh = sb_getblk(&Vcb->sb, block);
            }

            if (!bh) {
                DEBUG(DL_ERR, ("Ext2SaveBuffer: can't load block %I64u\n", block));
                DbgBreak();
                __leave;
            }

            if (!buffer_uptodate(bh)) {
	            int err = bh_submit_read(bh);
	            if (err < 0) {
		            DEBUG(DL_ERR, ("Ext2SaveBuffer: bh_submit_read failed: %d\n", err));
		            __leave;
	            }
            }

            __try {
                if (delta == 0 && len >= BLOCK_SIZE) {
                    /* bh (cache) was already cleaned as zero */
                } else {
                    RtlZeroMemory(bh->b_data + delta, len);
                }
                mark_buffer_dirty(bh);
            } __finally {
                fini_bh(&bh);
            }

            offset = offset + len;
            size = size - len;
        }