raid1.rar_raid1

/* * raid1.c : Multiple Devices driver for Linux * * * * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000 * * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk> * Various fixes by Neil Brown <neilb@cse.unsw.edu.au> * * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support * bitmapped intelligence in resync: * * - bitmap marked during normal i/o * - bitmap used to skip nondirty blocks during sync * * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology: * - persistent bitmap code * * 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. */ #include <linux/slab.h> #include <linux/delay.h> #include <linux/blkdev.h> #include <linux/seq_file.h> #include "md.h" #include "raid1.h" #include "bitmap.h" #define DEBUG 0 #if DEBUG #define PRINTK(x...) printk(x) #else #define PRINTK(x...) #endif /* * Number of guaranteed r1bios in case of extreme VM load: */ #define NR_RAID1_BIOS 256 static void allow_barrier(conf_t *conf); static void lower_barrier(conf_t *conf); static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data) { struct pool_info *pi = data; int size = offsetof(r1bio_t, bios[pi->raid_disks]); /* allocate a r1bio with room for raid_disks entries in the bios array */ return kzalloc(size, gfp_flags); } static void r1bio_pool_free(void *r1_bio, void *data) { kfree(r1_bio); } #define RESYNC_BLOCK_SIZE (64*1024) //#define RESYNC_BLOCK_SIZE PAGE_SIZE #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) #define RESYNC_WINDOW (2048*1024) static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data) { struct pool_info *pi = data; struct page *page; r1bio_t *r1_bio; struct bio *bio; int i, j; r1_bio = r1bio_pool_alloc(gfp_flags, pi); if (!r1_bio) return NULL; /* * Allocate bios : 1 for reading, n-1 for writing */ for (j = pi->raid_disks ; j-- ; ) { bio = bio_kmalloc(gfp_flags, RESYNC_PAGES); if (!bio) goto out_free_bio; r1_bio->bios[j] = bio; } /* * Allocate RESYNC_PAGES data pages and attach them to * the first bio. * If this is a user-requested check/repair, allocate * RESYNC_PAGES for each bio. */ if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) j = pi->raid_disks; else j = 1; while(j--) { bio = r1_bio->bios[j]; for (i = 0; i < RESYNC_PAGES; i++) { page = alloc_page(gfp_flags); if (unlikely(!page)) goto out_free_pages; bio->bi_io_vec[i].bv_page = page; bio->bi_vcnt = i+1; } } /* If not user-requests, copy the page pointers to all bios */ if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) { for (i=0; i<RESYNC_PAGES ; i++) for (j=1; j<pi->raid_disks; j++) r1_bio->bios[j]->bi_io_vec[i].bv_page = r1_bio->bios[0]->bi_io_vec[i].bv_page; } r1_bio->master_bio = NULL; return r1_bio; out_free_pages: for (j=0 ; j < pi->raid_disks; j++) for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++) put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page); j = -1; out_free_bio: while ( ++j < pi->raid_disks ) bio_put(r1_bio->bios[j]); r1bio_pool_free(r1_bio, data); return NULL; } static void r1buf_pool_free(void *__r1_bio, void *data) { struct pool_info *pi = data; int i,j; r1bio_t *r1bio = __r1_bio; for (i = 0; i < RESYNC_PAGES; i++) for (j = pi->raid_disks; j-- ;) { if (j == 0 || r1bio->bios[j]->bi_io_vec[i].bv_page != r1bio->bios[0]->bi_io_vec[i].bv_page) safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page); } for (i=0 ; i < pi->raid_disks; i++) bio_put(r1bio->bios[i]); r1bio_pool_free(r1bio, data); } static void put_all_bios(conf_t *conf, r1bio_t *r1_bio) { int i; for (i = 0; i < conf->raid_disks; i++) { struct bio **bio = r1_bio->bios + i; if (*bio && *bio != IO_BLOCKED) bio_put(*bio); *bio = NULL; } } static void free_r1bio(r1bio_t *r1_bio) { conf_t *conf = r1_bio->mddev->private; /* * Wake up any possible resync thread that waits for the device * to go idle. */ allow_barrier(conf); put_all_bios(conf, r1_bio); mempool_free(r1_bio, conf->r1bio_pool); } static void put_buf(r1bio_t *r1_bio) { conf_t *conf = r1_bio->mddev->private; int i; for (i=0; i<conf->raid_disks; i++) { struct bio *bio = r1_bio->bios[i]; if (bio->bi_end_io) rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev); } mempool_free(r1_bio, conf->r1buf_pool); lower_barrier(conf); } static void reschedule_retry(r1bio_t *r1_bio) { unsigned long flags; mddev_t *mddev = r1_bio->mddev; conf_t *conf = mddev->private; spin_lock_irqsave(&conf->device_lock, flags); list_add(&r1_bio->retry_list, &conf->retry_list); conf->nr_queued ++; spin_unlock_irqrestore(&conf->device_lock, flags); wake_up(&conf->wait_barrier); md_wakeup_thread(mddev->thread); } /* * raid_end_bio_io() is called when we have finished servicing a mirrored * operation and are ready to return a success/failure code to the buffer * cache layer. */ static void raid_end_bio_io(r1bio_t *r1_bio) { struct bio *bio = r1_bio->master_bio; /* if nobody has done the final endio yet, do it now */ if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) { PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n", (bio_data_dir(bio) == WRITE) ? "write" : "read", (unsigned long long) bio->bi_sector, (unsigned long long) bio->bi_sector + (bio->bi_size >> 9) - 1); bio_endio(bio, test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO); } free_r1bio(r1_bio); } /* * Update disk head position estimator based on IRQ completion info. */ static inline void update_head_pos(int disk, r1bio_t *r1_bio) { conf_t *conf = r1_bio->mddev->private; conf->mirrors[disk].head_position = r1_bio->sector + (r1_bio->sectors); } static void raid1_end_read_request(struct bio *bio, int error) { int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); r1bio_t *r1_bio = bio->bi_private; int mirror; conf_t *conf = r1_bio->mddev->private; mirror = r1_bio->read_disk; /* * this branch is our 'one mirror IO has finished' event handler: */ update_head_pos(mirror, r1_bio); if (uptodate) set_bit(R1BIO_Uptodate, &r1_bio->state); else { /* If all other devices have failed, we want to return * the error upwards rather than fail the last device. * Here we redefine "uptodate" to mean "Don't want to retry" */ unsigned long flags; spin_lock_irqsave(&conf->device_lock, flags); if (r1_bio->mddev->degraded == conf->raid_disks || (r1_bio->mddev->degraded == conf->raid_disks-1 && !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags))) uptodate = 1; spin_unlock_irqrestore(&conf->device_lock, flags); } if (uptodate) raid_end_bio_io(r1_bio); else { /* * oops, read error: */ char b[BDEVNAME_SIZE]; if (printk_ratelimit()) printk(KERN_ERR "md/raid1:%s: %s: rescheduling sector %llu\n", mdname(conf->mddev), bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector); reschedule_retry(r1_bio); } rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev); } static void r1_bio_write_done(r1bio_t *r1_bio) { if (atomic_dec_and_test(&r1_bio->remaining)) { /* it really is the end of this request */ if (test_bit(R1BIO_BehindIO, &r1_bio->state)) { /* free extra copy of the data pages */ int i = r1_bio->behind_page_count; while (i--) safe_put_page(r1_bio->behind_pages[i]); kfree(r1_bio->behind_pages); r1_bio->behind_pages = NULL; } /* clear the bitmap if all writes complete successfully */ bitmap_endwr