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