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authorAsias He <asias@redhat.com>2013-02-25 14:03:43 +0800
committerNicholas Bellinger <nab@linux-iscsi.org>2013-04-25 01:05:23 -0700
commit506427628afeb5d70eefdac1fe4c2a1ffb27df5f (patch)
treecd487389e9013909b44032d115f279944fea7a73 /drivers/target
parent70d3ae5c80758cb2bf3cf1e0d5b2c89d040de90b (diff)
downloadlinux-506427628afeb5d70eefdac1fe4c2a1ffb27df5f.tar.gz
target/file: Add UNMAP emulation support
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(). Cc: Christoph Hellwig <hch@lst.de> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_file.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index e1878bfd97b..7e02304a102 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>
@@ -525,6 +526,115 @@ 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;
+ }
+ }
+
+ 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;
@@ -684,6 +794,7 @@ 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