v4.19.13 snapshot.
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
new file mode 100644
index 0000000..32aabe2
--- /dev/null
+++ b/drivers/md/dm-flakey.c
@@ -0,0 +1,504 @@
+/*
+ * Copyright (C) 2003 Sistina Software (UK) Limited.
+ * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/device-mapper.h>
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+
+#define DM_MSG_PREFIX "flakey"
+
+#define all_corrupt_bio_flags_match(bio, fc) \
+ (((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
+
+/*
+ * Flakey: Used for testing only, simulates intermittent,
+ * catastrophic device failure.
+ */
+struct flakey_c {
+ struct dm_dev *dev;
+ unsigned long start_time;
+ sector_t start;
+ unsigned up_interval;
+ unsigned down_interval;
+ unsigned long flags;
+ unsigned corrupt_bio_byte;
+ unsigned corrupt_bio_rw;
+ unsigned corrupt_bio_value;
+ unsigned corrupt_bio_flags;
+};
+
+enum feature_flag_bits {
+ DROP_WRITES,
+ ERROR_WRITES
+};
+
+struct per_bio_data {
+ bool bio_submitted;
+};
+
+static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
+ struct dm_target *ti)
+{
+ int r;
+ unsigned argc;
+ const char *arg_name;
+
+ static const struct dm_arg _args[] = {
+ {0, 6, "Invalid number of feature args"},
+ {1, UINT_MAX, "Invalid corrupt bio byte"},
+ {0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
+ {0, UINT_MAX, "Invalid corrupt bio flags mask"},
+ };
+
+ /* No feature arguments supplied. */
+ if (!as->argc)
+ return 0;
+
+ r = dm_read_arg_group(_args, as, &argc, &ti->error);
+ if (r)
+ return r;
+
+ while (argc) {
+ arg_name = dm_shift_arg(as);
+ argc--;
+
+ if (!arg_name) {
+ ti->error = "Insufficient feature arguments";
+ return -EINVAL;
+ }
+
+ /*
+ * drop_writes
+ */
+ if (!strcasecmp(arg_name, "drop_writes")) {
+ if (test_and_set_bit(DROP_WRITES, &fc->flags)) {
+ ti->error = "Feature drop_writes duplicated";
+ return -EINVAL;
+ } else if (test_bit(ERROR_WRITES, &fc->flags)) {
+ ti->error = "Feature drop_writes conflicts with feature error_writes";
+ return -EINVAL;
+ }
+
+ continue;
+ }
+
+ /*
+ * error_writes
+ */
+ if (!strcasecmp(arg_name, "error_writes")) {
+ if (test_and_set_bit(ERROR_WRITES, &fc->flags)) {
+ ti->error = "Feature error_writes duplicated";
+ return -EINVAL;
+
+ } else if (test_bit(DROP_WRITES, &fc->flags)) {
+ ti->error = "Feature error_writes conflicts with feature drop_writes";
+ return -EINVAL;
+ }
+
+ continue;
+ }
+
+ /*
+ * corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>
+ */
+ if (!strcasecmp(arg_name, "corrupt_bio_byte")) {
+ if (!argc) {
+ ti->error = "Feature corrupt_bio_byte requires parameters";
+ return -EINVAL;
+ }
+
+ r = dm_read_arg(_args + 1, as, &fc->corrupt_bio_byte, &ti->error);
+ if (r)
+ return r;
+ argc--;
+
+ /*
+ * Direction r or w?
+ */
+ arg_name = dm_shift_arg(as);
+ if (!strcasecmp(arg_name, "w"))
+ fc->corrupt_bio_rw = WRITE;
+ else if (!strcasecmp(arg_name, "r"))
+ fc->corrupt_bio_rw = READ;
+ else {
+ ti->error = "Invalid corrupt bio direction (r or w)";
+ return -EINVAL;
+ }
+ argc--;
+
+ /*
+ * Value of byte (0-255) to write in place of correct one.
+ */
+ r = dm_read_arg(_args + 2, as, &fc->corrupt_bio_value, &ti->error);
+ if (r)
+ return r;
+ argc--;
+
+ /*
+ * Only corrupt bios with these flags set.
+ */
+ r = dm_read_arg(_args + 3, as, &fc->corrupt_bio_flags, &ti->error);
+ if (r)
+ return r;
+ argc--;
+
+ continue;
+ }
+
+ ti->error = "Unrecognised flakey feature requested";
+ return -EINVAL;
+ }
+
+ if (test_bit(DROP_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
+ ti->error = "drop_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
+ return -EINVAL;
+
+ } else if (test_bit(ERROR_WRITES, &fc->flags) && (fc->corrupt_bio_rw == WRITE)) {
+ ti->error = "error_writes is incompatible with corrupt_bio_byte with the WRITE flag set";
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * Construct a flakey mapping:
+ * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
+ *
+ * Feature args:
+ * [drop_writes]
+ * [corrupt_bio_byte <Nth_byte> <direction> <value> <bio_flags>]
+ *
+ * Nth_byte starts from 1 for the first byte.
+ * Direction is r for READ or w for WRITE.
+ * bio_flags is ignored if 0.
+ */
+static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ static const struct dm_arg _args[] = {
+ {0, UINT_MAX, "Invalid up interval"},
+ {0, UINT_MAX, "Invalid down interval"},
+ };
+
+ int r;
+ struct flakey_c *fc;
+ unsigned long long tmpll;
+ struct dm_arg_set as;
+ const char *devname;
+ char dummy;
+
+ as.argc = argc;
+ as.argv = argv;
+
+ if (argc < 4) {
+ ti->error = "Invalid argument count";
+ return -EINVAL;
+ }
+
+ fc = kzalloc(sizeof(*fc), GFP_KERNEL);
+ if (!fc) {
+ ti->error = "Cannot allocate context";
+ return -ENOMEM;
+ }
+ fc->start_time = jiffies;
+
+ devname = dm_shift_arg(&as);
+
+ r = -EINVAL;
+ if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
+ ti->error = "Invalid device sector";
+ goto bad;
+ }
+ fc->start = tmpll;
+
+ r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
+ if (r)
+ goto bad;
+
+ r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
+ if (r)
+ goto bad;
+
+ if (!(fc->up_interval + fc->down_interval)) {
+ ti->error = "Total (up + down) interval is zero";
+ r = -EINVAL;
+ goto bad;
+ }
+
+ if (fc->up_interval + fc->down_interval < fc->up_interval) {
+ ti->error = "Interval overflow";
+ r = -EINVAL;
+ goto bad;
+ }
+
+ r = parse_features(&as, fc, ti);
+ if (r)
+ goto bad;
+
+ r = dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev);
+ if (r) {
+ ti->error = "Device lookup failed";
+ goto bad;
+ }
+
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
+ ti->per_io_data_size = sizeof(struct per_bio_data);
+ ti->private = fc;
+ return 0;
+
+bad:
+ kfree(fc);
+ return r;
+}
+
+static void flakey_dtr(struct dm_target *ti)
+{
+ struct flakey_c *fc = ti->private;
+
+ dm_put_device(ti, fc->dev);
+ kfree(fc);
+}
+
+static sector_t flakey_map_sector(struct dm_target *ti, sector_t bi_sector)
+{
+ struct flakey_c *fc = ti->private;
+
+ return fc->start + dm_target_offset(ti, bi_sector);
+}
+
+static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
+{
+ struct flakey_c *fc = ti->private;
+
+ bio_set_dev(bio, fc->dev->bdev);
+ if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)
+ bio->bi_iter.bi_sector =
+ flakey_map_sector(ti, bio->bi_iter.bi_sector);
+}
+
+static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc)
+{
+ unsigned bio_bytes = bio_cur_bytes(bio);
+ char *data = bio_data(bio);
+
+ /*
+ * Overwrite the Nth byte of the data returned.
+ */
+ if (data && bio_bytes >= fc->corrupt_bio_byte) {
+ data[fc->corrupt_bio_byte - 1] = fc->corrupt_bio_value;
+
+ DMDEBUG("Corrupting data bio=%p by writing %u to byte %u "
+ "(rw=%c bi_opf=%u bi_sector=%llu cur_bytes=%u)\n",
+ bio, fc->corrupt_bio_value, fc->corrupt_bio_byte,
+ (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf,
+ (unsigned long long)bio->bi_iter.bi_sector, bio_bytes);
+ }
+}
+
+static int flakey_map(struct dm_target *ti, struct bio *bio)
+{
+ struct flakey_c *fc = ti->private;
+ unsigned elapsed;
+ struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
+ pb->bio_submitted = false;
+
+ /* Do not fail reset zone */
+ if (bio_op(bio) == REQ_OP_ZONE_RESET)
+ goto map_bio;
+
+ /* We need to remap reported zones, so remember the BIO iter */
+ if (bio_op(bio) == REQ_OP_ZONE_REPORT)
+ goto map_bio;
+
+ /* Are we alive ? */
+ elapsed = (jiffies - fc->start_time) / HZ;
+ if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
+ /*
+ * Flag this bio as submitted while down.
+ */
+ pb->bio_submitted = true;
+
+ /*
+ * Error reads if neither corrupt_bio_byte or drop_writes or error_writes are set.
+ * Otherwise, flakey_end_io() will decide if the reads should be modified.
+ */
+ if (bio_data_dir(bio) == READ) {
+ if (!fc->corrupt_bio_byte && !test_bit(DROP_WRITES, &fc->flags) &&
+ !test_bit(ERROR_WRITES, &fc->flags))
+ return DM_MAPIO_KILL;
+ goto map_bio;
+ }
+
+ /*
+ * Drop or error writes?
+ */
+ if (test_bit(DROP_WRITES, &fc->flags)) {
+ bio_endio(bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+ else if (test_bit(ERROR_WRITES, &fc->flags)) {
+ bio_io_error(bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ /*
+ * Corrupt matching writes.
+ */
+ if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == WRITE)) {
+ if (all_corrupt_bio_flags_match(bio, fc))
+ corrupt_bio_data(bio, fc);
+ goto map_bio;
+ }
+
+ /*
+ * By default, error all I/O.
+ */
+ return DM_MAPIO_KILL;
+ }
+
+map_bio:
+ flakey_map_bio(ti, bio);
+
+ return DM_MAPIO_REMAPPED;
+}
+
+static int flakey_end_io(struct dm_target *ti, struct bio *bio,
+ blk_status_t *error)
+{
+ struct flakey_c *fc = ti->private;
+ struct per_bio_data *pb = dm_per_bio_data(bio, sizeof(struct per_bio_data));
+
+ if (bio_op(bio) == REQ_OP_ZONE_RESET)
+ return DM_ENDIO_DONE;
+
+ if (bio_op(bio) == REQ_OP_ZONE_REPORT) {
+ dm_remap_zone_report(ti, bio, fc->start);
+ return DM_ENDIO_DONE;
+ }
+
+ if (!*error && pb->bio_submitted && (bio_data_dir(bio) == READ)) {
+ if (fc->corrupt_bio_byte && (fc->corrupt_bio_rw == READ) &&
+ all_corrupt_bio_flags_match(bio, fc)) {
+ /*
+ * Corrupt successful matching READs while in down state.
+ */
+ corrupt_bio_data(bio, fc);
+
+ } else if (!test_bit(DROP_WRITES, &fc->flags) &&
+ !test_bit(ERROR_WRITES, &fc->flags)) {
+ /*
+ * Error read during the down_interval if drop_writes
+ * and error_writes were not configured.
+ */
+ *error = BLK_STS_IOERR;
+ }
+ }
+
+ return DM_ENDIO_DONE;
+}
+
+static void flakey_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
+{
+ unsigned sz = 0;
+ struct flakey_c *fc = ti->private;
+ unsigned drop_writes, error_writes;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ result[0] = '\0';
+ break;
+
+ case STATUSTYPE_TABLE:
+ DMEMIT("%s %llu %u %u ", fc->dev->name,
+ (unsigned long long)fc->start, fc->up_interval,
+ fc->down_interval);
+
+ drop_writes = test_bit(DROP_WRITES, &fc->flags);
+ error_writes = test_bit(ERROR_WRITES, &fc->flags);
+ DMEMIT("%u ", drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5);
+
+ if (drop_writes)
+ DMEMIT("drop_writes ");
+ else if (error_writes)
+ DMEMIT("error_writes ");
+
+ if (fc->corrupt_bio_byte)
+ DMEMIT("corrupt_bio_byte %u %c %u %u ",
+ fc->corrupt_bio_byte,
+ (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r',
+ fc->corrupt_bio_value, fc->corrupt_bio_flags);
+
+ break;
+ }
+}
+
+static int flakey_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
+{
+ struct flakey_c *fc = ti->private;
+
+ *bdev = fc->dev->bdev;
+
+ /*
+ * Only pass ioctls through if the device sizes match exactly.
+ */
+ if (fc->start ||
+ ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
+ return 1;
+ return 0;
+}
+
+static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
+{
+ struct flakey_c *fc = ti->private;
+
+ return fn(ti, fc->dev, fc->start, ti->len, data);
+}
+
+static struct target_type flakey_target = {
+ .name = "flakey",
+ .version = {1, 5, 0},
+#ifdef CONFIG_BLK_DEV_ZONED
+ .features = DM_TARGET_ZONED_HM,
+#endif
+ .module = THIS_MODULE,
+ .ctr = flakey_ctr,
+ .dtr = flakey_dtr,
+ .map = flakey_map,
+ .end_io = flakey_end_io,
+ .status = flakey_status,
+ .prepare_ioctl = flakey_prepare_ioctl,
+ .iterate_devices = flakey_iterate_devices,
+};
+
+static int __init dm_flakey_init(void)
+{
+ int r = dm_register_target(&flakey_target);
+
+ if (r < 0)
+ DMERR("register failed %d", r);
+
+ return r;
+}
+
+static void __exit dm_flakey_exit(void)
+{
+ dm_unregister_target(&flakey_target);
+}
+
+/* Module hooks */
+module_init(dm_flakey_init);
+module_exit(dm_flakey_exit);
+
+MODULE_DESCRIPTION(DM_NAME " flakey target");
+MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");