Date: Tue, 31 Jul 2018 23:44:14 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-vendor@freebsd.org Subject: svn commit: r337022 - vendor-sys/illumos/dist/uts/common/fs/zfs Message-ID: <201807312344.w6VNiEem021630@repo.freebsd.org>
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Author: mav Date: Tue Jul 31 23:44:13 2018 New Revision: 337022 URL: https://svnweb.freebsd.org/changeset/base/337022 Log: 9403 assertion failed in arc_buf_destroy() when concurrently reading block with checksum error This assertion (VERIFY) failure was reported when reading a block. Turns out the problem is that if we get an i/o error (ECKSUM in this case), and there are multiple concurrent ARC reads of the same block (from different clones), then the ARC will put multiple buf's on the same ANON hdr, which isn't supposed to happen, and then causes a panic when we try to arc_buf_destroy() the buf. illumos/illumos-gate@fa98e487a9619b7902f218663be219e787a57dad Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Paul Dagnelie <pcd@delphix.com> Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com> Approved by: Matt Ahrens <mahrens@delphix.com> Author: Matthew Ahrens <mahrens@delphix.com> Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c vendor-sys/illumos/dist/uts/common/fs/zfs/dbuf.c vendor-sys/illumos/dist/uts/common/fs/zfs/zio_compress.c Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c ============================================================================== --- vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c Tue Jul 31 23:00:58 2018 (r337021) +++ vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c Tue Jul 31 23:44:13 2018 (r337022) @@ -21,7 +21,7 @@ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2018, Joyent, Inc. - * Copyright (c) 2011, 2017 by Delphix. All rights reserved. + * Copyright (c) 2011, 2018 by Delphix. All rights reserved. * Copyright (c) 2014 by Saso Kiselkov. All rights reserved. * Copyright 2017 Nexenta Systems, Inc. All rights reserved. */ @@ -4717,12 +4717,13 @@ void arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) { arc_buf_t **bufp = arg; - if (zio && zio->io_error) { - arc_buf_destroy(buf, arg); + if (buf == NULL) { + ASSERT(zio == NULL || zio->io_error != 0); *bufp = NULL; } else { + ASSERT(zio == NULL || zio->io_error == 0); *bufp = buf; - ASSERT(buf->b_data); + ASSERT(buf->b_data != NULL); } } @@ -4821,12 +4822,38 @@ arc_read_done(zio_t *zio) /* This is a demand read since prefetches don't use callbacks */ callback_cnt++; - int error = arc_buf_alloc_impl(hdr, acb->acb_private, - acb->acb_compressed, no_zio_error, &acb->acb_buf); if (no_zio_error) { - zio->io_error = error; + int error = arc_buf_alloc_impl(hdr, acb->acb_private, + acb->acb_compressed, zio->io_error == 0, + &acb->acb_buf); + if (error != 0) { + /* + * Decompression failed. Set io_error + * so that when we call acb_done (below), + * we will indicate that the read failed. + * Note that in the unusual case where one + * callback is compressed and another + * uncompressed, we will mark all of them + * as failed, even though the uncompressed + * one can't actually fail. In this case, + * the hdr will not be anonymous, because + * if there are multiple callbacks, it's + * because multiple threads found the same + * arc buf in the hash table. + */ + zio->io_error = error; + } } } + /* + * If there are multiple callbacks, we must have the hash lock, + * because the only way for multiple threads to find this hdr is + * in the hash table. This ensures that if there are multiple + * callbacks, the hdr is not anonymous. If it were anonymous, + * we couldn't use arc_buf_destroy() in the error case below. + */ + ASSERT(callback_cnt < 2 || hash_lock != NULL); + hdr->b_l1hdr.b_acb = NULL; arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); if (callback_cnt == 0) { @@ -4871,8 +4898,18 @@ arc_read_done(zio_t *zio) /* execute each callback and free its structure */ while ((acb = callback_list) != NULL) { - if (acb->acb_done) + if (acb->acb_done != NULL) { + if (zio->io_error != 0 && acb->acb_buf != NULL) { + /* + * If arc_buf_alloc_impl() fails during + * decompression, the buf will still be + * allocated, and needs to be freed here. + */ + arc_buf_destroy(acb->acb_buf, acb->acb_private); + acb->acb_buf = NULL; + } acb->acb_done(zio, acb->acb_buf, acb->acb_private); + } if (acb->acb_zio_dummy != NULL) { acb->acb_zio_dummy->io_error = zio->io_error; Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/dbuf.c ============================================================================== --- vendor-sys/illumos/dist/uts/common/fs/zfs/dbuf.c Tue Jul 31 23:00:58 2018 (r337021) +++ vendor-sys/illumos/dist/uts/common/fs/zfs/dbuf.c Tue Jul 31 23:44:13 2018 (r337022) @@ -21,7 +21,7 @@ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright 2011 Nexenta Systems, Inc. All rights reserved. - * Copyright (c) 2012, 2017 by Delphix. All rights reserved. + * Copyright (c) 2012, 2018 by Delphix. All rights reserved. * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. * Copyright (c) 2013, Joyent, Inc. All rights reserved. * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. @@ -989,22 +989,26 @@ dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb) ASSERT(refcount_count(&db->db_holds) > 0); ASSERT(db->db_buf == NULL); ASSERT(db->db.db_data == NULL); - if (db->db_level == 0 && db->db_freed_in_flight) { - /* we were freed in flight; disregard any error */ + if (buf == NULL) { + /* i/o error */ + ASSERT(zio == NULL || zio->io_error != 0); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + ASSERT3P(db->db_buf, ==, NULL); + db->db_state = DB_UNCACHED; + } else if (db->db_level == 0 && db->db_freed_in_flight) { + /* freed in flight */ + ASSERT(zio == NULL || zio->io_error == 0); arc_release(buf, db); bzero(buf->b_data, db->db.db_size); arc_buf_freeze(buf); db->db_freed_in_flight = FALSE; dbuf_set_data(db, buf); db->db_state = DB_CACHED; - } else if (zio == NULL || zio->io_error == 0) { + } else { + /* success */ + ASSERT(zio == NULL || zio->io_error == 0); dbuf_set_data(db, buf); db->db_state = DB_CACHED; - } else { - ASSERT(db->db_blkid != DMU_BONUS_BLKID); - ASSERT3P(db->db_buf, ==, NULL); - arc_buf_destroy(buf, db); - db->db_state = DB_UNCACHED; } cv_broadcast(&db->db_changed); dbuf_rele_and_unlock(db, NULL); @@ -2417,6 +2421,13 @@ dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abu ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); ASSERT3S(dpa->dpa_curlevel, >, 0); + if (abuf == NULL) { + ASSERT(zio == NULL || zio->io_error != 0); + kmem_free(dpa, sizeof (*dpa)); + return; + } + ASSERT(zio == NULL || zio->io_error == 0); + /* * The dpa_dnode is only valid if we are called with a NULL * zio. This indicates that the arc_read() returned without @@ -2455,7 +2466,7 @@ dbuf_prefetch_indirect_done(zio_t *zio, arc_buf_t *abu (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); blkptr_t *bp = ((blkptr_t *)abuf->b_data) + P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); - if (BP_IS_HOLE(bp) || (zio != NULL && zio->io_error != 0)) { + if (BP_IS_HOLE(bp)) { kmem_free(dpa, sizeof (*dpa)); } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/zio_compress.c ============================================================================== --- vendor-sys/illumos/dist/uts/common/fs/zfs/zio_compress.c Tue Jul 31 23:00:58 2018 (r337021) +++ vendor-sys/illumos/dist/uts/common/fs/zfs/zio_compress.c Tue Jul 31 23:44:13 2018 (r337022) @@ -25,7 +25,7 @@ */ /* * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. - * Copyright (c) 2013, 2016 by Delphix. All rights reserved. + * Copyright (c) 2013, 2018 by Delphix. All rights reserved. */ #include <sys/zfs_context.h> @@ -36,6 +36,12 @@ #include <sys/zio_compress.h> /* + * If nonzero, every 1/X decompression attempts will fail, simulating + * an undetected memory error. + */ +uint64_t zio_decompress_fail_fraction = 0; + +/* * Compression vectors. */ zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = { @@ -145,6 +151,16 @@ zio_decompress_data(enum zio_compress c, abd_t *src, v void *tmp = abd_borrow_buf_copy(src, s_len); int ret = zio_decompress_data_buf(c, tmp, dst, s_len, d_len); abd_return_buf(src, tmp, s_len); + + /* + * Decompression shouldn't fail, because we've already verifyied + * the checksum. However, for extra protection (e.g. against bitflips + * in non-ECC RAM), we handle this error (and test it). + */ + ASSERT0(ret); + if (zio_decompress_fail_fraction != 0 && + spa_get_random(zio_decompress_fail_fraction) == 0) + ret = SET_ERROR(EINVAL); return (ret); }
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