Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 343 insertions, 0 deletions

diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
new file mode 100644
index 000000000000..0248f8e7eac0
--- /dev/null
+++ b/drivers/md/faulty.c
@@ -0,0 +1,343 @@
+/*
+ * faulty.c : Multiple Devices driver for Linux
+ *
+ * Copyright (C) 2004 Neil Brown
+ *
+ * fautly-device-simulator personality for md
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * You should have received a copy of the GNU General Public License
+ * (for example /usr/src/linux/COPYING); if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+/*
+ * The "faulty" personality causes some requests to fail.
+ *
+ * Possible failure modes are:
+ *   reads fail "randomly" but succeed on retry
+ *   writes fail "randomly" but succeed on retry
+ *   reads for some address fail and then persist until a write
+ *   reads for some address fail and then persist irrespective of write
+ *   writes for some address fail and persist
+ *   all writes fail
+ *
+ * Different modes can be active at a time, but only
+ * one can be set at array creation.  Others can be added later.
+ * A mode can be one-shot or recurrent with the recurrance being
+ * once in every N requests.
+ * The bottom 5 bits of the "layout" indicate the mode.  The
+ * remainder indicate a period, or 0 for one-shot.
+ *
+ * There is an implementation limit on the number of concurrently
+ * persisting-faulty blocks. When a new fault is requested that would
+ * exceed the limit, it is ignored.
+ * All current faults can be clear using a layout of "0".
+ *
+ * Requests are always sent to the device.  If they are to fail,
+ * we clone the bio and insert a new b_end_io into the chain.
+ */
+
+#define WriteTransient  0
+#define ReadTransient   1
+#define WritePersistent 2
+#define ReadPersistent  3
+#define WriteAll        4 /* doesn't go to device */
+#define ReadFixable     5
+#define Modes   6
+
+#define ClearErrors     31
+#define ClearFaults     30
+
+#define AllPersist      100 /* internal use only */
+#define NoPersist       101
+
+#define ModeMask        0x1f
+#define ModeShift       5
+
+#define MaxFault        50
+#include <linux/raid/md.h>
+
+
+static int faulty_fail(struct bio *bio, unsigned int bytes_done, int error)
+{
+        struct bio *b = bio->bi_private;
+
+        b->bi_size = bio->bi_size;
+        b->bi_sector = bio->bi_sector;
+
+        if (bio->bi_size == 0)
+                bio_put(bio);
+
+        clear_bit(BIO_UPTODATE, &b->bi_flags);
+        return (b->bi_end_io)(b, bytes_done, -EIO);
+}
+
+typedef struct faulty_conf {
+        int period[Modes];
+        atomic_t counters[Modes];
+        sector_t faults[MaxFault];
+        int     modes[MaxFault];
+        int nfaults;
+        mdk_rdev_t *rdev;
+} conf_t;
+
+static int check_mode(conf_t *conf, int mode)
+{
+        if (conf->period[mode] == 0 &&
+            atomic_read(&conf->counters[mode]) <= 0)
+                return 0; /* no failure, no decrement */
+
+
+        if (atomic_dec_and_test(&conf->counters[mode])) {
+                if (conf->period[mode])
+                        atomic_set(&conf->counters[mode], conf->period[mode]);
+                return 1;
+        }
+        return 0;
+}
+
+static int check_sector(conf_t *conf, sector_t start, sector_t end, int dir)
+{
+        /* If we find a ReadFixable sector, we fix it ... */
+        int i;
+        for (i=0; i<conf->nfaults; i++)
+                if (conf->faults[i] >= start &&
+                    conf->faults[i] < end) {
+                        /* found it ... */
+                        switch (conf->modes[i] * 2 + dir) {
+                        case WritePersistent*2+WRITE: return 1;
+                        case ReadPersistent*2+READ: return 1;
+                        case ReadFixable*2+READ: return 1;
+                        case ReadFixable*2+WRITE:
+                                conf->modes[i] = NoPersist;
+                                return 0;
+                        case AllPersist*2+READ:
+                        case AllPersist*2+WRITE: return 1;
+                        default:
+                                return 0;
+                        }
+                }
+        return 0;
+}
+
+static void add_sector(conf_t *conf, sector_t start, int mode)
+{
+        int i;
+        int n = conf->nfaults;
+        for (i=0; i<conf->nfaults; i++)
+                if (conf->faults[i] == start) {
+                        switch(mode) {
+                        case NoPersist: conf->modes[i] = mode; return;
+                        case WritePersistent:
+                                if (conf->modes[i] == ReadPersistent ||
+                                    conf->modes[i] == ReadFixable)
+                                        conf->modes[i] = AllPersist;
+                                else
+                                        conf->modes[i] = WritePersistent;
+                                return;
+                        case ReadPersistent:
+                                if (conf->modes[i] == WritePersistent)
+                                        conf->modes[i] = AllPersist;
+                                else
+                                        conf->modes[i] = ReadPersistent;
+                                return;
+                        case ReadFixable:
+                                if (conf->modes[i] == WritePersistent ||
+                                    conf->modes[i] == ReadPersistent)
+                                        conf->modes[i] = AllPersist;
+                                else
+                                        conf->modes[i] = ReadFixable;
+                                return;
+                        }
+                } else if (conf->modes[i] == NoPersist)
+                        n = i;
+
+        if (n >= MaxFault)
+                return;
+        conf->faults[n] = start;
+        conf->modes[n] = mode;
+        if (conf->nfaults == n)
+                conf->nfaults = n+1;
+}
+
+static int make_request(request_queue_t *q, struct bio *bio)
+{
+        mddev_t *mddev = q->queuedata;
+        conf_t *conf = (conf_t*)mddev->private;
+        int failit = 0;
+
+        if (bio->bi_rw & 1) {
+                /* write request */
+                if (atomic_read(&conf->counters[WriteAll])) {
+                        /* special case - don't decrement, don't generic_make_request,
+                         * just fail immediately
+                         */
+                        bio_endio(bio, bio->bi_size, -EIO);
+                        return 0;
+                }
+
+                if (check_sector(conf, bio->bi_sector, bio->bi_sector+(bio->bi_size>>9),
+                                 WRITE))
+                        failit = 1;
+                if (check_mode(conf, WritePersistent)) {
+                        add_sector(conf, bio->bi_sector, WritePersistent);
+                        failit = 1;
+                }
+                if (check_mode(conf, WriteTransient))
+                        failit = 1;
+        } else {
+                /* read request */
+                if (check_sector(conf, bio->bi_sector, bio->bi_sector + (bio->bi_size>>9),
+                                 READ))
+                        failit = 1;
+                if (check_mode(conf, ReadTransient))
+                        failit = 1;
+                if (check_mode(conf, ReadPersistent)) {
+                        add_sector(conf, bio->bi_sector, ReadPersistent);
+                        failit = 1;
+                }
+                if (check_mode(conf, ReadFixable)) {
+                        add_sector(conf, bio->bi_sector, ReadFixable);
+                        failit = 1;
+                }
+        }
+        if (failit) {
+                struct bio *b = bio_clone(bio, GFP_NOIO);
+                b->bi_bdev = conf->rdev->bdev;
+                b->bi_private = bio;
+                b->bi_end_io = faulty_fail;
+                generic_make_request(b);
+                return 0;
+        } else {
+                bio->bi_bdev = conf->rdev->bdev;
+                return 1;
+        }
+}
+
+static void status(struct seq_file *seq, mddev_t *mddev)
+{
+        conf_t *conf = (conf_t*)mddev->private;
+        int n;
+
+        if ((n=atomic_read(&conf->counters[WriteTransient])) != 0)
+                seq_printf(seq, " WriteTransient=%d(%d)",
+                           n, conf->period[WriteTransient]);
+
+        if ((n=atomic_read(&conf->counters[ReadTransient])) != 0)
+                seq_printf(seq, " ReadTransient=%d(%d)",
+                           n, conf->period[ReadTransient]);
+
+        if ((n=atomic_read(&conf->counters[WritePersistent])) != 0)
+                seq_printf(seq, " WritePersistent=%d(%d)",
+                           n, conf->period[WritePersistent]);
+
+        if ((n=atomic_read(&conf->counters[ReadPersistent])) != 0)
+                seq_printf(seq, " ReadPersistent=%d(%d)",
+                           n, conf->period[ReadPersistent]);
+
+
+        if ((n=atomic_read(&conf->counters[ReadFixable])) != 0)
+                seq_printf(seq, " ReadFixable=%d(%d)",
+                           n, conf->period[ReadFixable]);
+
+        if ((n=atomic_read(&conf->counters[WriteAll])) != 0)
+                seq_printf(seq, " WriteAll");
+
+        seq_printf(seq, " nfaults=%d", conf->nfaults);
+}
+
+
+static int reconfig(mddev_t *mddev, int layout, int chunk_size)
+{
+        int mode = layout & ModeMask;
+        int count = layout >> ModeShift;
+        conf_t *conf = mddev->private;
+
+        if (chunk_size != -1)
+                return -EINVAL;
+
+        /* new layout */
+        if (mode == ClearFaults)
+                conf->nfaults = 0;
+        else if (mode == ClearErrors) {
+                int i;
+                for (i=0 ; i < Modes ; i++) {
+                        conf->period[i] = 0;
+                        atomic_set(&conf->counters[i], 0);
+                }
+        } else if (mode < Modes) {
+                conf->period[mode] = count;
+                if (!count) count++;
+                atomic_set(&conf->counters[mode], count);
+        } else
+                return -EINVAL;
+        mddev->layout = -1; /* makes sure further changes come through */
+        return 0;
+}
+
+static int run(mddev_t *mddev)
+{
+        mdk_rdev_t *rdev;
+        struct list_head *tmp;
+        int i;
+
+        conf_t *conf = kmalloc(sizeof(*conf), GFP_KERNEL);
+
+        for (i=0; i<Modes; i++) {
+                atomic_set(&conf->counters[i], 0);
+                conf->period[i] = 0;
+        }
+        conf->nfaults = 0;
+
+        ITERATE_RDEV(mddev, rdev, tmp)
+                conf->rdev = rdev;
+
+        mddev->array_size = mddev->size;
+        mddev->private = conf;
+
+        reconfig(mddev, mddev->layout, -1);
+
+        return 0;
+}
+
+static int stop(mddev_t *mddev)
+{
+        conf_t *conf = (conf_t *)mddev->private;
+
+        kfree(conf);
+        mddev->private = NULL;
+        return 0;
+}
+
+static mdk_personality_t faulty_personality =
+{
+        .name           = "faulty",
+        .owner          = THIS_MODULE,
+        .make_request   = make_request,
+        .run            = run,
+        .stop           = stop,
+        .status         = status,
+        .reconfig       = reconfig,
+};
+
+static int __init raid_init(void)
+{
+        return register_md_personality(FAULTY, &faulty_personality);
+}
+
+static void raid_exit(void)
+{
+        unregister_md_personality(FAULTY);
+}
+
+module_init(raid_init);
+module_exit(raid_exit);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("md-personality-10"); /* faulty */