/*
* Copyright (C) 2003 Sistina Software (UK) Limited.
- * Copyright (C) 2004, 2010 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004, 2010-2011 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#define DM_MSG_PREFIX "flakey"
+#define all_corrupt_bio_flags_match(bio, fc) \
+ (((bio)->bi_rw & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags)
+
/*
* Flakey: Used for testing only, simulates intermittent,
* catastrophic device failure.
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
};
+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 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--;
+
+ /*
+ * 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;
+ }
+
+ 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";
+
+ 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;
+ }
+
+ return 0;
+}
+
/*
- * Construct a flakey mapping: <dev_path> <offset> <up interval> <down interval>
+ * 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 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 tmp;
+ unsigned long long tmpll;
+ struct dm_arg_set as;
+ const char *devname;
- if (argc != 4) {
- ti->error = "dm-flakey: Invalid argument count";
+ as.argc = argc;
+ as.argv = argv;
+
+ if (argc < 4) {
+ ti->error = "Invalid argument count";
return -EINVAL;
}
- fc = kmalloc(sizeof(*fc), GFP_KERNEL);
+ fc = kzalloc(sizeof(*fc), GFP_KERNEL);
if (!fc) {
- ti->error = "dm-flakey: Cannot allocate linear context";
+ ti->error = "Cannot allocate linear context";
return -ENOMEM;
}
fc->start_time = jiffies;
- if (sscanf(argv[1], "%llu", &tmp) != 1) {
- ti->error = "dm-flakey: Invalid device sector";
+ devname = dm_shift_arg(&as);
+
+ if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 1) {
+ ti->error = "Invalid device sector";
goto bad;
}
- fc->start = tmp;
+ fc->start = tmpll;
- if (sscanf(argv[2], "%u", &fc->up_interval) != 1) {
- ti->error = "dm-flakey: Invalid up interval";
+ r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
+ if (r)
goto bad;
- }
- if (sscanf(argv[3], "%u", &fc->down_interval) != 1) {
- ti->error = "dm-flakey: Invalid down interval";
+ r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
+ if (r)
goto bad;
- }
if (!(fc->up_interval + fc->down_interval)) {
- ti->error = "dm-flakey: Total (up + down) interval is zero";
+ ti->error = "Total (up + down) interval is zero";
goto bad;
}
if (fc->up_interval + fc->down_interval < fc->up_interval) {
- ti->error = "dm-flakey: Interval overflow";
+ ti->error = "Interval overflow";
goto bad;
}
- if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &fc->dev)) {
- ti->error = "dm-flakey: Device lookup failed";
+ r = parse_features(&as, fc, ti);
+ if (r)
+ goto bad;
+
+ if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
+ ti->error = "Device lookup failed";
goto bad;
}
ti->num_flush_requests = 1;
+ ti->num_discard_requests = 1;
ti->private = fc;
return 0;
{
struct flakey_c *fc = ti->private;
- return fc->start + (bi_sector - ti->begin);
+ return fc->start + dm_target_offset(ti, bi_sector);
}
static void flakey_map_bio(struct dm_target *ti, struct bio *bio)
bio->bi_sector = flakey_map_sector(ti, bio->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_rw=%lu 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_rw, (unsigned long long)bio->bi_sector, bio_bytes);
+ }
+}
+
static int flakey_map(struct dm_target *ti, struct bio *bio,
union map_info *map_context)
{
/* Are we alive ? */
elapsed = (jiffies - fc->start_time) / HZ;
- if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval)
+ if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) {
+ /*
+ * Flag this bio as submitted while down.
+ */
+ map_context->ll = 1;
+
+ /*
+ * Map reads as normal.
+ */
+ if (bio_data_dir(bio) == READ)
+ goto map_bio;
+
+ /*
+ * Drop writes?
+ */
+ if (test_bit(DROP_WRITES, &fc->flags)) {
+ bio_endio(bio, 0);
+ 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 -EIO;
+ }
+map_bio:
flakey_map_bio(ti, bio);
return DM_MAPIO_REMAPPED;
}
+static int flakey_end_io(struct dm_target *ti, struct bio *bio,
+ int error, union map_info *map_context)
+{
+ struct flakey_c *fc = ti->private;
+ unsigned bio_submitted_while_down = map_context->ll;
+
+ /*
+ * Corrupt successful READs while in down state.
+ * If flags were specified, only corrupt those that match.
+ */
+ if (!error && bio_submitted_while_down &&
+ (bio_data_dir(bio) == READ) && (fc->corrupt_bio_rw == READ) &&
+ all_corrupt_bio_flags_match(bio, fc))
+ corrupt_bio_data(bio, fc);
+
+ return error;
+}
+
static int flakey_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
+ unsigned sz = 0;
struct flakey_c *fc = ti->private;
+ unsigned drop_writes;
switch (type) {
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
- snprintf(result, maxlen, "%s %llu %u %u", fc->dev->name,
- (unsigned long long)fc->start, fc->up_interval,
- fc->down_interval);
+ 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);
+ DMEMIT("%u ", drop_writes + (fc->corrupt_bio_byte > 0) * 5);
+
+ if (drop_writes)
+ DMEMIT("drop_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;
}
return 0;
static struct target_type flakey_target = {
.name = "flakey",
- .version = {1, 1, 0},
+ .version = {1, 2, 0},
.module = THIS_MODULE,
.ctr = flakey_ctr,
.dtr = flakey_dtr,
.map = flakey_map,
+ .end_io = flakey_end_io,
.status = flakey_status,
.ioctl = flakey_ioctl,
.merge = flakey_merge,
git.openpandora.org / pandora-kernel.git / blobdiff