md/r5cache: handle alloc_page failure
RMW of r5c write back cache uses an extra page to store old data for prexor. handle_stripe_dirtying() allocates this page by calling alloc_page(). However, alloc_page() may fail. To handle alloc_page() failures, this patch adds an extra page to disk_info. When alloc_page fails, handle_stripe() trys to use these pages. When these pages are used by other stripe (R5C_EXTRA_PAGE_IN_USE), the stripe is added to delayed_list. Signed-off-by: Song Liu <songliubraving@fb.com> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
This commit is contained in:
Song Liu
Shaohua Li
parent
034e33f5ed
commit
d7bd398e97
3 changed files with 98 additions and 13 deletions
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@ -2326,15 +2326,40 @@ int r5c_try_caching_write(struct r5conf *conf,
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*/
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void r5c_release_extra_page(struct stripe_head *sh)
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{
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struct r5conf *conf = sh->raid_conf;
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int i;
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bool using_disk_info_extra_page;
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using_disk_info_extra_page =
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sh->dev[0].orig_page == conf->disks[0].extra_page;
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for (i = sh->disks; i--; )
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if (sh->dev[i].page != sh->dev[i].orig_page) {
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struct page *p = sh->dev[i].orig_page;
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sh->dev[i].orig_page = sh->dev[i].page;
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put_page(p);
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if (!using_disk_info_extra_page)
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put_page(p);
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}
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if (using_disk_info_extra_page) {
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clear_bit(R5C_EXTRA_PAGE_IN_USE, &conf->cache_state);
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md_wakeup_thread(conf->mddev->thread);
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}
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}
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void r5c_use_extra_page(struct stripe_head *sh)
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{
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struct r5conf *conf = sh->raid_conf;
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int i;
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struct r5dev *dev;
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for (i = sh->disks; i--; ) {
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dev = &sh->dev[i];
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if (dev->orig_page != dev->page)
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put_page(dev->orig_page);
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dev->orig_page = conf->disks[i].extra_page;
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}
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}
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/*
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@ -876,6 +876,8 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
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if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
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/* writing out phase */
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if (s->waiting_extra_page)
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return;
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if (r5l_write_stripe(conf->log, sh) == 0)
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return;
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} else { /* caching phase */
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@ -2007,6 +2009,7 @@ static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
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INIT_LIST_HEAD(&sh->batch_list);
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INIT_LIST_HEAD(&sh->lru);
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INIT_LIST_HEAD(&sh->r5c);
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INIT_LIST_HEAD(&sh->log_list);
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atomic_set(&sh->count, 1);
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sh->log_start = MaxSector;
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for (i = 0; i < disks; i++) {
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@ -2253,10 +2256,24 @@ static int resize_stripes(struct r5conf *conf, int newsize)
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*/
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ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
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if (ndisks) {
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for (i=0; i<conf->raid_disks; i++)
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for (i = 0; i < conf->pool_size; i++)
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ndisks[i] = conf->disks[i];
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kfree(conf->disks);
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conf->disks = ndisks;
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for (i = conf->pool_size; i < newsize; i++) {
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ndisks[i].extra_page = alloc_page(GFP_NOIO);
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if (!ndisks[i].extra_page)
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err = -ENOMEM;
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}
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if (err) {
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for (i = conf->pool_size; i < newsize; i++)
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if (ndisks[i].extra_page)
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put_page(ndisks[i].extra_page);
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kfree(ndisks);
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} else {
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kfree(conf->disks);
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conf->disks = ndisks;
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}
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} else
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err = -ENOMEM;
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@ -3580,10 +3597,10 @@ unhash:
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break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
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}
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static void handle_stripe_dirtying(struct r5conf *conf,
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struct stripe_head *sh,
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struct stripe_head_state *s,
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int disks)
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static int handle_stripe_dirtying(struct r5conf *conf,
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struct stripe_head *sh,
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struct stripe_head_state *s,
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int disks)
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{
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int rmw = 0, rcw = 0, i;
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sector_t recovery_cp = conf->mddev->recovery_cp;
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@ -3649,12 +3666,32 @@ static void handle_stripe_dirtying(struct r5conf *conf,
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dev->page == dev->orig_page &&
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!test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
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/* alloc page for prexor */
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dev->orig_page = alloc_page(GFP_NOIO);
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struct page *p = alloc_page(GFP_NOIO);
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/* will handle failure in a later patch*/
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BUG_ON(!dev->orig_page);
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if (p) {
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dev->orig_page = p;
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continue;
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}
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/*
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* alloc_page() failed, try use
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* disk_info->extra_page
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*/
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if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
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&conf->cache_state)) {
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r5c_use_extra_page(sh);
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break;
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}
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/* extra_page in use, add to delayed_list */
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set_bit(STRIPE_DELAYED, &sh->state);
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s->waiting_extra_page = 1;
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return -EAGAIN;
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}
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}
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for (i = disks; i--; ) {
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struct r5dev *dev = &sh->dev[i];
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if ((dev->towrite ||
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i == sh->pd_idx || i == sh->qd_idx ||
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test_bit(R5_InJournal, &dev->flags)) &&
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@ -3730,6 +3767,7 @@ static void handle_stripe_dirtying(struct r5conf *conf,
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(s->locked == 0 && (rcw == 0 || rmw == 0) &&
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!test_bit(STRIPE_BIT_DELAY, &sh->state)))
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schedule_reconstruction(sh, s, rcw == 0, 0);
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return 0;
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}
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static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
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@ -4545,8 +4583,12 @@ static void handle_stripe(struct stripe_head *sh)
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if (ret == -EAGAIN ||
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/* stripe under reclaim: !caching && injournal */
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(!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
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s.injournal > 0))
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handle_stripe_dirtying(conf, sh, &s, disks);
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s.injournal > 0)) {
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ret = handle_stripe_dirtying(conf, sh, &s,
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disks);
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if (ret == -EAGAIN)
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goto finish;
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}
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}
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}
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@ -6458,6 +6500,8 @@ static void raid5_free_percpu(struct r5conf *conf)
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static void free_conf(struct r5conf *conf)
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{
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int i;
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if (conf->log)
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r5l_exit_log(conf->log);
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if (conf->shrinker.nr_deferred)
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@ -6466,6 +6510,9 @@ static void free_conf(struct r5conf *conf)
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free_thread_groups(conf);
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shrink_stripes(conf);
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raid5_free_percpu(conf);
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for (i = 0; i < conf->pool_size; i++)
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if (conf->disks[i].extra_page)
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put_page(conf->disks[i].extra_page);
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kfree(conf->disks);
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kfree(conf->stripe_hashtbl);
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kfree(conf);
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@ -6612,9 +6659,16 @@ static struct r5conf *setup_conf(struct mddev *mddev)
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conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
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GFP_KERNEL);
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if (!conf->disks)
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goto abort;
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for (i = 0; i < max_disks; i++) {
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conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
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if (!conf->disks[i].extra_page)
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goto abort;
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}
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conf->mddev = mddev;
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if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
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@ -276,6 +276,7 @@ struct stripe_head_state {
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struct md_rdev *blocked_rdev;
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int handle_bad_blocks;
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int log_failed;
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int waiting_extra_page;
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};
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/* Flags for struct r5dev.flags */
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@ -439,6 +440,7 @@ enum {
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struct disk_info {
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struct md_rdev *rdev, *replacement;
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struct page *extra_page; /* extra page to use in prexor */
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};
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/*
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@ -559,6 +561,9 @@ enum r5_cache_state {
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* only process stripes that are already
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* occupying the log
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*/
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R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page
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* for prexor
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*/
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};
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struct r5conf {
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@ -765,6 +770,7 @@ extern void
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r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh,
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struct stripe_head_state *s);
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extern void r5c_release_extra_page(struct stripe_head *sh);
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extern void r5c_use_extra_page(struct stripe_head *sh);
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extern void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
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extern void r5c_handle_cached_data_endio(struct r5conf *conf,
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struct stripe_head *sh, int disks, struct bio_list *return_bi);
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