[PATCH] md: tidyup some issues with raid1 resync and prepare for catching read errors
We are dereferencing ->rdev without an rcu lock! Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
NeilBrown
Linus Torvalds
parent
ddaf22abaa
commit
3e198f7826
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@ -177,6 +177,13 @@ static inline void free_r1bio(r1bio_t *r1_bio)
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static inline void put_buf(r1bio_t *r1_bio)
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{
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conf_t *conf = mddev_to_conf(r1_bio->mddev);
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int i;
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for (i=0; i<conf->raid_disks; i++) {
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struct bio *bio = r1_bio->bios[i];
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if (bio->bi_end_io)
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rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
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}
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mempool_free(r1_bio, conf->r1buf_pool);
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@ -1085,7 +1092,6 @@ static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
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conf->mirrors[r1_bio->read_disk].rdev);
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} else
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set_bit(R1BIO_Uptodate, &r1_bio->state);
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rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
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reschedule_retry(r1_bio);
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return 0;
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}
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@ -1116,7 +1122,6 @@ static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
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md_done_sync(mddev, r1_bio->sectors, uptodate);
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put_buf(r1_bio);
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}
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rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
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return 0;
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}
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@ -1153,10 +1158,14 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
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atomic_set(&r1_bio->remaining, 1);
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for (i = 0; i < disks ; i++) {
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wbio = r1_bio->bios[i];
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if (wbio->bi_end_io != end_sync_write)
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if (wbio->bi_end_io == NULL ||
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(wbio->bi_end_io == end_sync_read &&
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(i == r1_bio->read_disk ||
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!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
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continue;
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atomic_inc(&conf->mirrors[i].rdev->nr_pending);
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wbio->bi_rw = WRITE;
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wbio->bi_end_io = end_sync_write;
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atomic_inc(&r1_bio->remaining);
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md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
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@ -1388,14 +1397,13 @@ static int init_resync(conf_t *conf)
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static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
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{
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conf_t *conf = mddev_to_conf(mddev);
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mirror_info_t *mirror;
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r1bio_t *r1_bio;
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struct bio *bio;
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sector_t max_sector, nr_sectors;
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int disk;
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int disk = -1;
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int i;
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int wonly;
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int write_targets = 0;
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int wonly = -1;
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int write_targets = 0, read_targets = 0;
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int sync_blocks;
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int still_degraded = 0;
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@ -1447,44 +1455,24 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
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conf->next_resync = sector_nr;
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/*
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* If reconstructing, and >1 working disc,
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* could dedicate one to rebuild and others to
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* service read requests ..
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*/
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disk = conf->last_used;
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/* make sure disk is operational */
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wonly = disk;
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while (conf->mirrors[disk].rdev == NULL ||
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!test_bit(In_sync, &conf->mirrors[disk].rdev->flags) ||
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test_bit(WriteMostly, &conf->mirrors[disk].rdev->flags)
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) {
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if (conf->mirrors[disk].rdev &&
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test_bit(In_sync, &conf->mirrors[disk].rdev->flags))
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wonly = disk;
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if (disk <= 0)
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disk = conf->raid_disks;
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disk--;
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if (disk == conf->last_used) {
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disk = wonly;
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break;
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}
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}
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conf->last_used = disk;
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atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
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mirror = conf->mirrors + disk;
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r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
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rcu_read_lock();
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/*
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* If we get a correctably read error during resync or recovery,
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* we might want to read from a different device. So we
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* flag all drives that could conceivably be read from for READ,
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* and any others (which will be non-In_sync devices) for WRITE.
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* If a read fails, we try reading from something else for which READ
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* is OK.
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*/
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r1_bio->mddev = mddev;
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r1_bio->sector = sector_nr;
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r1_bio->state = 0;
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set_bit(R1BIO_IsSync, &r1_bio->state);
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r1_bio->read_disk = disk;
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for (i=0; i < conf->raid_disks; i++) {
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mdk_rdev_t *rdev;
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bio = r1_bio->bios[i];
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/* take from bio_init */
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@ -1499,35 +1487,49 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
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bio->bi_end_io = NULL;
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bio->bi_private = NULL;
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if (i == disk) {
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bio->bi_rw = READ;
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bio->bi_end_io = end_sync_read;
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} else if (conf->mirrors[i].rdev == NULL ||
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test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
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rdev = rcu_dereference(conf->mirrors[i].rdev);
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if (rdev == NULL ||
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test_bit(Faulty, &rdev->flags)) {
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still_degraded = 1;
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continue;
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} else if (!test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
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sector_nr + RESYNC_SECTORS > mddev->recovery_cp ||
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test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
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} else if (!test_bit(In_sync, &rdev->flags)) {
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bio->bi_rw = WRITE;
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bio->bi_end_io = end_sync_write;
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write_targets ++;
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} else
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/* no need to read or write here */
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continue;
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bio->bi_sector = sector_nr + conf->mirrors[i].rdev->data_offset;
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bio->bi_bdev = conf->mirrors[i].rdev->bdev;
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} else {
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/* may need to read from here */
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bio->bi_rw = READ;
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bio->bi_end_io = end_sync_read;
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if (test_bit(WriteMostly, &rdev->flags)) {
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if (wonly < 0)
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wonly = i;
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} else {
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if (disk < 0)
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disk = i;
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}
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read_targets++;
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}
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atomic_inc(&rdev->nr_pending);
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bio->bi_sector = sector_nr + rdev->data_offset;
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bio->bi_bdev = rdev->bdev;
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bio->bi_private = r1_bio;
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}
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rcu_read_unlock();
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if (disk < 0)
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disk = wonly;
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r1_bio->read_disk = disk;
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if (write_targets == 0) {
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if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
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/* extra read targets are also write targets */
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write_targets += read_targets-1;
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if (write_targets == 0 || read_targets == 0) {
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/* There is nowhere to write, so all non-sync
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* drives must be failed - so we are finished
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*/
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sector_t rv = max_sector - sector_nr;
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*skipped = 1;
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put_buf(r1_bio);
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rdev_dec_pending(conf->mirrors[disk].rdev, mddev);
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return rv;
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}
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@ -1578,10 +1580,10 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i
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sync_blocks -= (len>>9);
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} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
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bio_full:
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bio = r1_bio->bios[disk];
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bio = r1_bio->bios[r1_bio->read_disk];
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r1_bio->sectors = nr_sectors;
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md_sync_acct(mirror->rdev->bdev, nr_sectors);
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md_sync_acct(conf->mirrors[r1_bio->read_disk].rdev->bdev, nr_sectors);
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generic_make_request(bio);
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