On 02/22/2013 06:41 AM, Nicholas A. Bellinger wrote:
> On Thu, 2013-02-21 at 15:51 +0800, Asias He wrote:
>> This patch adds support for emulation of UNMAP within
>> fd_execute_unmap() backend code.
>>
>> If the FILEIO backend is normal file, the emulation uses fallocate to
>> punch hole to reclaim the free space used by the file. If the FILEIO
>> backend is block device, the emulation uses blkdev_issue_discard().
>>
>> TODO: fd_execute_unmap() is heavliy based on iblock_execute_unmap().
>> Will split out and share the common code.
>>
>> Cc: Christoph Hellwig <hch@xxxxxx>
>> Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
>> Cc: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>> Signed-off-by: Asias He <asias@xxxxxxxxxx>
>> ---
>> drivers/target/target_core_file.c | 111 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 111 insertions(+)
>>
>> diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
>> index 2a9ce12..b1359ef 100644
>> --- a/drivers/target/target_core_file.c
>> +++ b/drivers/target/target_core_file.c
>> @@ -33,6 +33,7 @@
>> #include <linux/falloc.h>
>> #include <scsi/scsi.h>
>> #include <scsi/scsi_host.h>
>> +#include <asm/unaligned.h>
>>
>> #include <target/target_core_base.h>
>> #include <target/target_core_backend.h>
>> @@ -489,6 +490,115 @@ fd_execute_write_same_unmap(struct se_cmd *cmd)
>> }
>>
>> static sense_reason_t
>> +fd_execute_unmap(struct se_cmd *cmd)
>> +{
>> + struct se_device *dev = cmd->se_dev;
>> + struct fd_dev *fd_dev = FD_DEV(dev);
>> + struct file *file = fd_dev->fd_file;
>> + struct inode *inode = file->f_mapping->host;
>> + unsigned char *buf, *ptr = NULL;
>> + sector_t lba;
>> + int size;
>> + u32 range;
>> + sense_reason_t ret = 0;
>> + int dl, bd_dl, err;
>> +
>> + /* We never set ANC_SUP */
>> + if (cmd->t_task_cdb[1])
>> + return TCM_INVALID_CDB_FIELD;
>> +
>> + if (cmd->data_length == 0) {
>> + target_complete_cmd(cmd, SAM_STAT_GOOD);
>> + return 0;
>> + }
>> +
>> + if (cmd->data_length < 8) {
>> + pr_warn("UNMAP parameter list length %u too small\n",
>> + cmd->data_length);
>> + return TCM_PARAMETER_LIST_LENGTH_ERROR;
>> + }
>> +
>> + buf = transport_kmap_data_sg(cmd);
>> + if (!buf)
>> + return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> +
>> + dl = get_unaligned_be16(&buf[0]);
>> + bd_dl = get_unaligned_be16(&buf[2]);
>> +
>> + size = cmd->data_length - 8;
>> + if (bd_dl > size)
>> + pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
>> + cmd->data_length, bd_dl);
>> + else
>> + size = bd_dl;
>> +
>> + if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
>> + ret = TCM_INVALID_PARAMETER_LIST;
>> + goto err;
>> + }
>> +
>> + /* First UNMAP block descriptor starts at 8 byte offset */
>> + ptr = &buf[8];
>> + pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
>> + " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
>> +
>> + while (size >= 16) {
>> + lba = get_unaligned_be64(&ptr[0]);
>> + range = get_unaligned_be32(&ptr[8]);
>> + pr_debug("UNMAP: Using lba: %llu and range: %u\n",
>> + (unsigned long long)lba, range);
>> +
>> + if (range > dev->dev_attrib.max_unmap_lba_count) {
>> + ret = TCM_INVALID_PARAMETER_LIST;
>> + goto err;
>> + }
>> +
>> + if (lba + range > dev->transport->get_blocks(dev) + 1) {
>> + ret = TCM_ADDRESS_OUT_OF_RANGE;
>> + goto err;
>> + }
>> +
>> + if (S_ISBLK(inode->i_mode)) {
>> + /* The backend is block device, use discard */
>> + struct block_device *bdev = inode->i_bdev;
>> +
>> + err = blkdev_issue_discard(bdev, lba, range, GFP_KERNEL, 0);
>> + if (err < 0) {
>> + pr_err("FILEIO: blkdev_issue_discard() failed: %d\n",
>> + err);
>> + ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> + goto err;
>> + }
>> + } else {
>> + /* The backend is normal file, use fallocate */
>> + loff_t pos = lba * dev->dev_attrib.block_size;
>> + unsigned int len = range * dev->dev_attrib.block_size;
>> + int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
>> +
>> + if (!file->f_op->fallocate) {
>> + ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> + goto err;
>> + }
>> + err = file->f_op->fallocate(file, mode, pos, len);
>> + if (err < 0) {
>> + pr_warn("FILEIO: fallocate() failed: %d\n", err);
>> + ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>> + goto err;
>> + }
>> + }
>> +
>
> Moving the if (S_ISBLK(inode->i_mode) { .. } else { .. } blocks into a
> separate function that can be shared by fd_execute_write_same_unmap()
> would save a few LOC here.
Yes, exactly. Also we only need !file->f_op->fallocate check once.
BTW, which file is the best place to put common code for
fd_execute_unmap() and iblock_execute_unmap().
> --nab
>
>> + ptr += 16;
>> + size -= 16;
>> + }
>> +
>> +err:
>> + transport_kunmap_data_sg(cmd);
>> + if (!ret)
>> + target_complete_cmd(cmd, GOOD);
>> + return ret;
>> +}
>> +
>> +static sense_reason_t
>> fd_execute_rw(struct se_cmd *cmd)
>> {
>> struct scatterlist *sgl = cmd->t_data_sg;
>> @@ -648,6 +758,7 @@ static struct sbc_ops fd_sbc_ops = {
>> .execute_sync_cache = fd_execute_sync_cache,
>> .execute_write_same = fd_execute_write_same,
>> .execute_write_same_unmap = fd_execute_write_same_unmap,
>> + .execute_unmap = fd_execute_unmap,
>> };
>>
>> static sense_reason_t
>
>
--
Asias
--
To unsubscribe from this list: send the line "unsubscribe target-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
