s390/dasd: Add new ioctl to release space

Userspace tools might have the need to release space for Extent Space
Efficient (ESE) volumes when working with such a device.

Provide the necessarry interface for such a task by implementing a new
ioctl BIODASDRAS. The ioctl uses the format_data_t data structure for
data input:

typedef struct format_data_t {
        unsigned int start_unit;        /* from track */
        unsigned int stop_unit;         /* to track */
        unsigned int blksize;           /* sectorsize */
        unsigned int intensity;
} format_data_t;

If the intensity is set to 0x40, start_unit and stop_unit are ignored
and space for the entire volume is released. Otherwise, if intensity is
set to 0, the respective range is released (if possible).

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

5 files changed, 364 insertions, 0 deletions

diff --git a/arch/s390/include/uapi/asm/dasd.h b/arch/s390/include/uapi/asm/dasd.h
index 48a2f475b90a..9ec86fae9980 100644
--- a/arch/s390/include/uapi/asm/dasd.h
+++ b/arch/s390/include/uapi/asm/dasd.h
@@ -194,6 +194,7 @@ typedef struct format_data_t {
 #define DASD_FMT_INT_INVAL      4       /* invalidate tracks */
 #define DASD_FMT_INT_COMPAT     8       /* use OS/390 compatible disk layout */
 #define DASD_FMT_INT_FMT_NOR0   16      /* remove permission to write record zero */
+#define DASD_FMT_INT_ESE_FULL   32      /* release space for entire volume */
 
 /*
  * struct format_check_t
@@ -323,6 +324,8 @@ struct dasd_snid_ioctl_data {
 #define BIODASDFMT     _IOW(DASD_IOCTL_LETTER,1,format_data_t)
 /* Set Attributes (cache operations) */
 #define BIODASDSATTR   _IOW(DASD_IOCTL_LETTER,2,attrib_data_t)
+/* Release Allocated Space */
+#define BIODASDRAS     _IOW(DASD_IOCTL_LETTER, 3, format_data_t)
 
 /* Get Sense Path Group ID (SNID) data */
 #define BIODASDSNID    _IOWR(DASD_IOCTL_LETTER, 1, struct dasd_snid_ioctl_data)
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 6109a0e68911..21164a48317d 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -3354,6 +3354,269 @@ static void dasd_eckd_check_for_device_change(struct dasd_device *device,
         }
 }
 
+static int dasd_eckd_ras_sanity_checks(struct dasd_device *device,
+                                       unsigned int first_trk,
+                                       unsigned int last_trk)
+{
+        struct dasd_eckd_private *private = device->private;
+        unsigned int trks_per_vol;
+        int rc = 0;
+
+        trks_per_vol = private->real_cyl * private->rdc_data.trk_per_cyl;
+
+        if (first_trk >= trks_per_vol) {
+                dev_warn(&device->cdev->dev,
+                         "Start track number %u used in the space release command is too big\n",
+                         first_trk);
+                rc = -EINVAL;
+        } else if (last_trk >= trks_per_vol) {
+                dev_warn(&device->cdev->dev,
+                         "Stop track number %u used in the space release command is too big\n",
+                         last_trk);
+                rc = -EINVAL;
+        } else if (first_trk > last_trk) {
+                dev_warn(&device->cdev->dev,
+                         "Start track %u used in the space release command exceeds the end track\n",
+                         first_trk);
+                rc = -EINVAL;
+        }
+        return rc;
+}
+
+/*
+ * Helper function to count the amount of involved extents within a given range
+ * with extent alignment in mind.
+ */
+static int count_exts(unsigned int from, unsigned int to, int trks_per_ext)
+{
+        int cur_pos = 0;
+        int count = 0;
+        int tmp;
+
+        if (from == to)
+                return 1;
+
+        /* Count first partial extent */
+        if (from % trks_per_ext != 0) {
+                tmp = from + trks_per_ext - (from % trks_per_ext) - 1;
+                if (tmp > to)
+                        tmp = to;
+                cur_pos = tmp - from + 1;
+                count++;
+        }
+        /* Count full extents */
+        if (to - (from + cur_pos) + 1 >= trks_per_ext) {
+                tmp = to - ((to - trks_per_ext + 1) % trks_per_ext);
+                count += (tmp - (from + cur_pos) + 1) / trks_per_ext;
+                cur_pos = tmp;
+        }
+        /* Count last partial extent */
+        if (cur_pos < to)
+                count++;
+
+        return count;
+}
+
+/*
+ * Release allocated space for a given range or an entire volume.
+ */
+static struct dasd_ccw_req *
+dasd_eckd_dso_ras(struct dasd_device *device, struct dasd_block *block,
+                  struct request *req, unsigned int first_trk,
+                  unsigned int last_trk, int by_extent)
+{
+        struct dasd_eckd_private *private = device->private;
+        struct dasd_dso_ras_ext_range *ras_range;
+        struct dasd_rssd_features *features;
+        struct dasd_dso_ras_data *ras_data;
+        u16 heads, beg_head, end_head;
+        int cur_to_trk, cur_from_trk;
+        struct dasd_ccw_req *cqr;
+        u32 beg_cyl, end_cyl;
+        struct ccw1 *ccw;
+        int trks_per_ext;
+        size_t ras_size;
+        size_t size;
+        int nr_exts;
+        void *rq;
+        int i;
+
+        if (dasd_eckd_ras_sanity_checks(device, first_trk, last_trk))
+                return ERR_PTR(-EINVAL);
+
+        rq = req ? blk_mq_rq_to_pdu(req) : NULL;
+
+        features = &private->features;
+
+        trks_per_ext = dasd_eckd_ext_size(device) * private->rdc_data.trk_per_cyl;
+        nr_exts = 0;
+        if (by_extent)
+                nr_exts = count_exts(first_trk, last_trk, trks_per_ext);
+        ras_size = sizeof(*ras_data);
+        size = ras_size + (nr_exts * sizeof(*ras_range));
+
+        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, size, device, rq);
+        if (IS_ERR(cqr)) {
+                DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
+                                "Could not allocate RAS request");
+                return cqr;
+        }
+
+        ras_data = cqr->data;
+        memset(ras_data, 0, size);
+
+        ras_data->order = DSO_ORDER_RAS;
+        ras_data->flags.vol_type = 0; /* CKD volume */
+        /* Release specified extents or entire volume */
+        ras_data->op_flags.by_extent = by_extent;
+        /*
+         * This bit guarantees initialisation of tracks within an extent that is
+         * not fully specified, but is only supported with a certain feature
+         * subset.
+         */
+        ras_data->op_flags.guarantee_init = !!(features->feature[56] & 0x01);
+        ras_data->lss = private->ned->ID;
+        ras_data->dev_addr = private->ned->unit_addr;
+        ras_data->nr_exts = nr_exts;
+
+        if (by_extent) {
+                heads = private->rdc_data.trk_per_cyl;
+                cur_from_trk = first_trk;
+                cur_to_trk = first_trk + trks_per_ext -
+                        (first_trk % trks_per_ext) - 1;
+                if (cur_to_trk > last_trk)
+                        cur_to_trk = last_trk;
+                ras_range = (struct dasd_dso_ras_ext_range *)(cqr->data + ras_size);
+
+                for (i = 0; i < nr_exts; i++) {
+                        beg_cyl = cur_from_trk / heads;
+                        beg_head = cur_from_trk % heads;
+                        end_cyl = cur_to_trk / heads;
+                        end_head = cur_to_trk % heads;
+
+                        set_ch_t(&ras_range->beg_ext, beg_cyl, beg_head);
+                        set_ch_t(&ras_range->end_ext, end_cyl, end_head);
+
+                        cur_from_trk = cur_to_trk + 1;
+                        cur_to_trk = cur_from_trk + trks_per_ext - 1;
+                        if (cur_to_trk > last_trk)
+                                cur_to_trk = last_trk;
+                        ras_range++;
+                }
+        }
+
+        ccw = cqr->cpaddr;
+        ccw->cda = (__u32)(addr_t)cqr->data;
+        ccw->cmd_code = DASD_ECKD_CCW_DSO;
+        ccw->count = size;
+
+        cqr->startdev = device;
+        cqr->memdev = device;
+        cqr->block = block;
+        cqr->retries = 256;
+        cqr->expires = device->default_expires * HZ;
+        cqr->buildclk = get_tod_clock();
+        cqr->status = DASD_CQR_FILLED;
+
+        return cqr;
+}
+
+static int dasd_eckd_release_space_full(struct dasd_device *device)
+{
+        struct dasd_ccw_req *cqr;
+        int rc;
+
+        cqr = dasd_eckd_dso_ras(device, NULL, NULL, 0, 0, 0);
+        if (IS_ERR(cqr))
+                return PTR_ERR(cqr);
+
+        rc = dasd_sleep_on_interruptible(cqr);
+
+        dasd_sfree_request(cqr, cqr->memdev);
+
+        return rc;
+}
+
+static int dasd_eckd_release_space_trks(struct dasd_device *device,
+                                        unsigned int from, unsigned int to)
+{
+        struct dasd_eckd_private *private = device->private;
+        struct dasd_block *block = device->block;
+        struct dasd_ccw_req *cqr, *n;
+        struct list_head ras_queue;
+        unsigned int device_exts;
+        int trks_per_ext;
+        int stop, step;
+        int cur_pos;
+        int rc = 0;
+        int retry;
+
+        INIT_LIST_HEAD(&ras_queue);
+
+        device_exts = private->real_cyl / dasd_eckd_ext_size(device);
+        trks_per_ext = dasd_eckd_ext_size(device) * private->rdc_data.trk_per_cyl;
+
+        /* Make sure device limits are not exceeded */
+        step = trks_per_ext * min(device_exts, DASD_ECKD_RAS_EXTS_MAX);
+        cur_pos = from;
+
+        do {
+                retry = 0;
+                while (cur_pos < to) {
+                        stop = cur_pos + step -
+                                ((cur_pos + step) % trks_per_ext) - 1;
+                        if (stop > to)
+                                stop = to;
+
+                        cqr = dasd_eckd_dso_ras(device, NULL, NULL, cur_pos, stop, 1);
+                        if (IS_ERR(cqr)) {
+                                rc = PTR_ERR(cqr);
+                                if (rc == -ENOMEM) {
+                                        if (list_empty(&ras_queue))
+                                                goto out;
+                                        retry = 1;
+                                        break;
+                                }
+                                goto err_out;
+                        }
+
+                        spin_lock_irq(&block->queue_lock);
+                        list_add_tail(&cqr->blocklist, &ras_queue);
+                        spin_unlock_irq(&block->queue_lock);
+                        cur_pos = stop + 1;
+                }
+
+                rc = dasd_sleep_on_queue_interruptible(&ras_queue);
+
+err_out:
+                list_for_each_entry_safe(cqr, n, &ras_queue, blocklist) {
+                        device = cqr->startdev;
+                        private = device->private;
+
+                        spin_lock_irq(&block->queue_lock);
+                        list_del_init(&cqr->blocklist);
+                        spin_unlock_irq(&block->queue_lock);
+                        dasd_sfree_request(cqr, device);
+                        private->count--;
+                }
+        } while (retry);
+
+out:
+        return rc;
+}
+
+static int dasd_eckd_release_space(struct dasd_device *device,
+                                   struct format_data_t *rdata)
+{
+        if (rdata->intensity & DASD_FMT_INT_ESE_FULL)
+                return dasd_eckd_release_space_full(device);
+        else if (rdata->intensity == 0)
+                return dasd_eckd_release_space_trks(device, rdata->start_unit,
+                                                    rdata->stop_unit);
+        else
+                return -EINVAL;
+}
+
 static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_single(
                                                struct dasd_device *startdev,
                                                struct dasd_block *block,
@@ -6162,6 +6425,7 @@ static struct dasd_discipline dasd_eckd_discipline = {
         .space_allocated = dasd_eckd_space_allocated,
         .space_configured = dasd_eckd_space_configured,
         .logical_capacity = dasd_eckd_logical_capacity,
+        .release_space = dasd_eckd_release_space,
         .ext_pool_id = dasd_eckd_ext_pool_id,
         .ext_size = dasd_eckd_ext_size,
         .ext_pool_cap_at_warnlevel = dasd_eckd_ext_pool_cap_at_warnlevel,
diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index bc5998068ddf..4226936427ec 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -50,6 +50,10 @@
 #define DASD_ECKD_CCW_PFX_READ           0xEA
 #define DASD_ECKD_CCW_RSCK               0xF9
 #define DASD_ECKD_CCW_RCD                0xFA
+#define DASD_ECKD_CCW_DSO                0xF7
+
+/* Define Subssystem Function / Orders */
+#define DSO_ORDER_RAS                    0x81
 
 /*
  * Perform Subsystem Function / Orders
@@ -513,6 +517,42 @@ struct dasd_psf_ssc_data {
         unsigned char reserved[59];
 } __attribute__((packed));
 
+/* Maximum number of extents for a single Release Allocated Space command */
+#define DASD_ECKD_RAS_EXTS_MAX          110U
+
+struct dasd_dso_ras_ext_range {
+        struct ch_t beg_ext;
+        struct ch_t end_ext;
+} __packed;
+
+/*
+ * Define Subsytem Operation - Release Allocated Space
+ */
+struct dasd_dso_ras_data {
+        __u8 order;
+        struct {
+                __u8 message:1;         /* Must be zero */
+                __u8 reserved1:2;
+                __u8 vol_type:1;        /* 0 - CKD/FBA, 1 - FB */
+                __u8 reserved2:4;
+        } __packed flags;
+        /* Operation Flags to specify scope */
+        struct {
+                __u8 reserved1:2;
+                /* Release Space by Extent */
+                __u8 by_extent:1;       /* 0 - entire volume, 1 - specified extents */
+                __u8 guarantee_init:1;
+                __u8 force_release:1;   /* Internal - will be ignored */
+                __u16 reserved2:11;
+        } __packed op_flags;
+        __u8 lss;
+        __u8 dev_addr;
+        __u32 reserved1;
+        __u8 reserved2[10];
+        __u16 nr_exts;                  /* Defines number of ext_scope - max 110 */
+        __u16 reserved3;
+} __packed;
+
 
 /*
  * some structures and definitions for alias handling
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 9a8ef372535b..7fe0c6b9d9ef 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -376,6 +376,7 @@ struct dasd_discipline {
         int (*space_allocated)(struct dasd_device *);
         int (*space_configured)(struct dasd_device *);
         int (*logical_capacity)(struct dasd_device *);
+        int (*release_space)(struct dasd_device *, struct format_data_t *);
         /* Extent Pool */
         int (*ext_pool_id)(struct dasd_device *);
         int (*ext_size)(struct dasd_device *);
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index 8e26001dc11c..9a5f3add325f 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -333,6 +333,59 @@ out_err:
         return rc;
 }
 
+static int dasd_release_space(struct dasd_device *device,
+                              struct format_data_t *rdata)
+{
+        if (!device->discipline->is_ese && !device->discipline->is_ese(device))
+                return -ENOTSUPP;
+        if (!device->discipline->release_space)
+                return -ENOTSUPP;
+
+        return device->discipline->release_space(device, rdata);
+}
+
+/*
+ * Release allocated space
+ */
+static int dasd_ioctl_release_space(struct block_device *bdev, void __user *argp)
+{
+        struct format_data_t rdata;
+        struct dasd_device *base;
+        int rc = 0;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+        if (!argp)
+                return -EINVAL;
+
+        base = dasd_device_from_gendisk(bdev->bd_disk);
+        if (!base)
+                return -ENODEV;
+        if (base->features & DASD_FEATURE_READONLY ||
+            test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) {
+                rc = -EROFS;
+                goto out_err;
+        }
+        if (bdev != bdev->bd_contains) {
+                pr_warn("%s: The specified DASD is a partition and tracks cannot be released\n",
+                        dev_name(&base->cdev->dev));
+                rc = -EINVAL;
+                goto out_err;
+        }
+
+        if (copy_from_user(&rdata, argp, sizeof(rdata))) {
+                rc = -EFAULT;
+                goto out_err;
+        }
+
+        rc = dasd_release_space(base, &rdata);
+
+out_err:
+        dasd_put_device(base);
+
+        return rc;
+}
+
 #ifdef CONFIG_DASD_PROFILE
 /*
  * Reset device profile information
@@ -595,6 +648,9 @@ int dasd_ioctl(struct block_device *bdev, fmode_t mode,
         case BIODASDREADALLCMB:
                 rc = dasd_ioctl_readall_cmb(block, cmd, argp);
                 break;
+        case BIODASDRAS:
+                rc = dasd_ioctl_release_space(bdev, argp);
+                break;
         default:
                 /* if the discipline has an ioctl method try it. */
                 rc = -ENOTTY;