From 664d487a5dbd758216ac613934a4080fcc1de347 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Sun, 7 Nov 2021 13:27:44 -0800 Subject: [PATCH] Fix lseek(SEEK_DATA/SEEK_HOLE) mmap consistency When using lseek(2) to report data/holes memory mapped regions of the file were ignored. This could result in incorrect results. To handle this zfs_holey_common() was updated to asynchronously writeback any dirty mmap(2) regions prior to reporting holes. Additionally, while not strictly required, the dn_struct_rwlock is now held over the dirty check to prevent the dnode structure from changing. This ensures that a clean dnode can't be dirtied before the data/hole is located. The range lock is now also taken to ensure the call cannot race with zfs_write(). Furthermore, the code was refactored to provide a dnode_is_dirty() helper function which checks the dnode for any dirty records to determine its dirtiness. Reviewed-by: Matthew Ahrens Reviewed-by: Tony Hutter Reviewed-by: Rich Ercolani Signed-off-by: Brian Behlendorf Issue #11900 Closes #12724 --- configure.ac | 1 + include/os/freebsd/spl/sys/vnode.h | 18 +++ include/os/freebsd/zfs/sys/zfs_znode_impl.h | 3 +- include/os/linux/zfs/sys/zfs_znode_impl.h | 1 + include/sys/dnode.h | 1 + man/man4/zfs.4 | 2 +- module/zfs/dmu.c | 53 ++++--- module/zfs/dnode.c | 20 +++ module/zfs/zfs_vnops.c | 9 +- tests/runfiles/common.run | 2 +- tests/zfs-tests/cmd/Makefile.am | 1 + tests/zfs-tests/cmd/mmap_seek/.gitignore | 1 + tests/zfs-tests/cmd/mmap_seek/Makefile.am | 6 + tests/zfs-tests/cmd/mmap_seek/mmap_seek.c | 147 ++++++++++++++++++ tests/zfs-tests/include/commands.cfg | 1 + tests/zfs-tests/include/tunables.cfg | 1 + .../tests/functional/mmap/Makefile.am | 3 +- .../functional/mmap/mmap_seek_001_pos.ksh | 67 ++++++++ 18 files changed, 305 insertions(+), 32 deletions(-) create mode 100644 tests/zfs-tests/cmd/mmap_seek/.gitignore create mode 100644 tests/zfs-tests/cmd/mmap_seek/Makefile.am create mode 100644 tests/zfs-tests/cmd/mmap_seek/mmap_seek.c create mode 100755 tests/zfs-tests/tests/functional/mmap/mmap_seek_001_pos.ksh diff --git a/configure.ac b/configure.ac index 6f34b210d2b..ebc7b276a64 100644 --- a/configure.ac +++ b/configure.ac @@ -221,6 +221,7 @@ AC_CONFIG_FILES([ tests/zfs-tests/cmd/mktree/Makefile tests/zfs-tests/cmd/mmap_exec/Makefile tests/zfs-tests/cmd/mmap_libaio/Makefile + tests/zfs-tests/cmd/mmap_seek/Makefile tests/zfs-tests/cmd/mmapwrite/Makefile tests/zfs-tests/cmd/nvlist_to_lua/Makefile tests/zfs-tests/cmd/randfree_file/Makefile diff --git a/include/os/freebsd/spl/sys/vnode.h b/include/os/freebsd/spl/sys/vnode.h index 3670712a045..3bc8a18eeb7 100644 --- a/include/os/freebsd/spl/sys/vnode.h +++ b/include/os/freebsd/spl/sys/vnode.h @@ -59,6 +59,8 @@ enum symfollow { NO_FOLLOW = NOFOLLOW }; #include #include #include +#include +#include typedef struct vop_vector vnodeops_t; #define VOP_FID VOP_VPTOFH @@ -83,6 +85,22 @@ vn_is_readonly(vnode_t *vp) #define vn_has_cached_data(vp) \ ((vp)->v_object != NULL && \ (vp)->v_object->resident_page_count > 0) + +static __inline void +vn_flush_cached_data(vnode_t *vp, boolean_t sync) +{ +#if __FreeBSD_version > 1300054 + if (vm_object_mightbedirty(vp->v_object)) { +#else + if (vp->v_object->flags & OBJ_MIGHTBEDIRTY) { +#endif + int flags = sync ? OBJPC_SYNC : 0; + zfs_vmobject_wlock(vp->v_object); + vm_object_page_clean(vp->v_object, 0, 0, flags); + zfs_vmobject_wunlock(vp->v_object); + } +} + #define vn_exists(vp) do { } while (0) #define vn_invalid(vp) do { } while (0) #define vn_renamepath(tdvp, svp, tnm, lentnm) do { } while (0) diff --git a/include/os/freebsd/zfs/sys/zfs_znode_impl.h b/include/os/freebsd/zfs/sys/zfs_znode_impl.h index e90008c70a8..edb28d041a0 100644 --- a/include/os/freebsd/zfs/sys/zfs_znode_impl.h +++ b/include/os/freebsd/zfs/sys/zfs_znode_impl.h @@ -118,7 +118,8 @@ extern minor_t zfsdev_minor_alloc(void); #define Z_ISLNK(type) ((type) == VLNK) #define Z_ISDIR(type) ((type) == VDIR) -#define zn_has_cached_data(zp) vn_has_cached_data(ZTOV(zp)) +#define zn_has_cached_data(zp) vn_has_cached_data(ZTOV(zp)) +#define zn_flush_cached_data(zp, sync) vn_flush_cached_data(ZTOV(zp), sync) #define zn_rlimit_fsize(zp, uio) \ vn_rlimit_fsize(ZTOV(zp), GET_UIO_STRUCT(uio), zfs_uio_td(uio)) diff --git a/include/os/linux/zfs/sys/zfs_znode_impl.h b/include/os/linux/zfs/sys/zfs_znode_impl.h index 0a6273442b7..de46fc8f2bd 100644 --- a/include/os/linux/zfs/sys/zfs_znode_impl.h +++ b/include/os/linux/zfs/sys/zfs_znode_impl.h @@ -71,6 +71,7 @@ extern "C" { #define Z_ISDIR(type) S_ISDIR(type) #define zn_has_cached_data(zp) ((zp)->z_is_mapped) +#define zn_flush_cached_data(zp, sync) write_inode_now(ZTOI(zp), sync) #define zn_rlimit_fsize(zp, uio) (0) /* diff --git a/include/sys/dnode.h b/include/sys/dnode.h index 2cdc5b8798a..af8775b9ee0 100644 --- a/include/sys/dnode.h +++ b/include/sys/dnode.h @@ -425,6 +425,7 @@ boolean_t dnode_add_ref(dnode_t *dn, void *ref); void dnode_rele(dnode_t *dn, void *ref); void dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting); int dnode_try_claim(objset_t *os, uint64_t object, int slots); +boolean_t dnode_is_dirty(dnode_t *dn); void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx); void dnode_set_dirtyctx(dnode_t *dn, dmu_tx_t *tx, void *tag); void dnode_sync(dnode_t *dn, dmu_tx_t *tx); diff --git a/man/man4/zfs.4 b/man/man4/zfs.4 index 2aed6895754..20b24d898d8 100644 --- a/man/man4/zfs.4 +++ b/man/man4/zfs.4 @@ -1574,7 +1574,7 @@ Allow no-operation writes. The occurrence of nopwrites will further depend on other pool properties .Pq i.a. the checksumming and compression algorithms . . -.It Sy zfs_dmu_offset_next_sync Ns = Ns Sy 0 Ns | ns 1 Pq int +.It Sy zfs_dmu_offset_next_sync Ns = Ns Sy 0 Ns | Ns 1 Pq int Enable forcing TXG sync to find holes. When enabled forces ZFS to act like prior versions when .Sy SEEK_HOLE No or Sy SEEK_DATA diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c index 1c47430953b..8302d506146 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -2095,42 +2095,41 @@ int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off) { dnode_t *dn; - int i, err; - boolean_t clean = B_TRUE; + int err; +restart: err = dnode_hold(os, object, FTAG, &dn); if (err) return (err); - /* - * Check if dnode is dirty - */ - for (i = 0; i < TXG_SIZE; i++) { - if (multilist_link_active(&dn->dn_dirty_link[i])) { - clean = B_FALSE; - break; - } - } + rw_enter(&dn->dn_struct_rwlock, RW_READER); - /* - * If compatibility option is on, sync any current changes before - * we go trundling through the block pointers. - */ - if (!clean && zfs_dmu_offset_next_sync) { - clean = B_TRUE; - dnode_rele(dn, FTAG); - txg_wait_synced(dmu_objset_pool(os), 0); - err = dnode_hold(os, object, FTAG, &dn); - if (err) - return (err); - } + if (dnode_is_dirty(dn)) { + /* + * If the zfs_dmu_offset_next_sync module option is enabled + * then strict hole reporting has been requested. Dirty + * dnodes must be synced to disk to accurately report all + * holes. When disabled (the default) dirty dnodes are + * reported to not have any holes which is always safe. + * + * When called by zfs_holey_common() the zp->z_rangelock + * is held to prevent zfs_write() and mmap writeback from + * re-dirtying the dnode after txg_wait_synced(). + */ + if (zfs_dmu_offset_next_sync) { + rw_exit(&dn->dn_struct_rwlock); + dnode_rele(dn, FTAG); + txg_wait_synced(dmu_objset_pool(os), 0); + goto restart; + } - if (clean) - err = dnode_next_offset(dn, - (hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0); - else err = SET_ERROR(EBUSY); + } else { + err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK | + (hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0); + } + rw_exit(&dn->dn_struct_rwlock); dnode_rele(dn, FTAG); return (err); diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c index 7f741542ce0..572d88ec2bf 100644 --- a/module/zfs/dnode.c +++ b/module/zfs/dnode.c @@ -1648,6 +1648,26 @@ dnode_try_claim(objset_t *os, uint64_t object, int slots) slots, NULL, NULL)); } +/* + * Checks if the dnode contains any uncommitted dirty records. + */ +boolean_t +dnode_is_dirty(dnode_t *dn) +{ + mutex_enter(&dn->dn_mtx); + + for (int i = 0; i < TXG_SIZE; i++) { + if (list_head(&dn->dn_dirty_records[i]) != NULL) { + mutex_exit(&dn->dn_mtx); + return (B_TRUE); + } + } + + mutex_exit(&dn->dn_mtx); + + return (B_FALSE); +} + void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx) { diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c index 8229bc9a93e..170e392abe9 100644 --- a/module/zfs/zfs_vnops.c +++ b/module/zfs/zfs_vnops.c @@ -85,6 +85,7 @@ zfs_fsync(znode_t *zp, int syncflag, cred_t *cr) static int zfs_holey_common(znode_t *zp, ulong_t cmd, loff_t *off) { + zfs_locked_range_t *lr; uint64_t noff = (uint64_t)*off; /* new offset */ uint64_t file_sz; int error; @@ -100,12 +101,18 @@ zfs_holey_common(znode_t *zp, ulong_t cmd, loff_t *off) else hole = B_FALSE; + /* Flush any mmap()'d data to disk */ + if (zn_has_cached_data(zp)) + zn_flush_cached_data(zp, B_FALSE); + + lr = zfs_rangelock_enter(&zp->z_rangelock, 0, file_sz, RL_READER); error = dmu_offset_next(ZTOZSB(zp)->z_os, zp->z_id, hole, &noff); + zfs_rangelock_exit(lr); if (error == ESRCH) return (SET_ERROR(ENXIO)); - /* file was dirty, so fall back to using generic logic */ + /* File was dirty, so fall back to using generic logic */ if (error == EBUSY) { if (hole) *off = file_sz; diff --git a/tests/runfiles/common.run b/tests/runfiles/common.run index a62cd6ad39f..97ee7b8ae24 100644 --- a/tests/runfiles/common.run +++ b/tests/runfiles/common.run @@ -669,7 +669,7 @@ tests = ['migration_001_pos', 'migration_002_pos', 'migration_003_pos', tags = ['functional', 'migration'] [tests/functional/mmap] -tests = ['mmap_write_001_pos', 'mmap_read_001_pos'] +tests = ['mmap_write_001_pos', 'mmap_read_001_pos', 'mmap_seek_001_pos'] tags = ['functional', 'mmap'] [tests/functional/mount] diff --git a/tests/zfs-tests/cmd/Makefile.am b/tests/zfs-tests/cmd/Makefile.am index 2b965ca7000..d1c29fcd1c6 100644 --- a/tests/zfs-tests/cmd/Makefile.am +++ b/tests/zfs-tests/cmd/Makefile.am @@ -19,6 +19,7 @@ SUBDIRS = \ mktree \ mmap_exec \ mmap_libaio \ + mmap_seek \ mmapwrite \ nvlist_to_lua \ randwritecomp \ diff --git a/tests/zfs-tests/cmd/mmap_seek/.gitignore b/tests/zfs-tests/cmd/mmap_seek/.gitignore new file mode 100644 index 00000000000..6b05a791750 --- /dev/null +++ b/tests/zfs-tests/cmd/mmap_seek/.gitignore @@ -0,0 +1 @@ +/mmap_seek diff --git a/tests/zfs-tests/cmd/mmap_seek/Makefile.am b/tests/zfs-tests/cmd/mmap_seek/Makefile.am new file mode 100644 index 00000000000..b938931125f --- /dev/null +++ b/tests/zfs-tests/cmd/mmap_seek/Makefile.am @@ -0,0 +1,6 @@ +include $(top_srcdir)/config/Rules.am + +pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/bin + +pkgexec_PROGRAMS = mmap_seek +mmap_seek_SOURCES = mmap_seek.c diff --git a/tests/zfs-tests/cmd/mmap_seek/mmap_seek.c b/tests/zfs-tests/cmd/mmap_seek/mmap_seek.c new file mode 100644 index 00000000000..f476e1dba9a --- /dev/null +++ b/tests/zfs-tests/cmd/mmap_seek/mmap_seek.c @@ -0,0 +1,147 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ + +/* + * Copyright (c) 2021 by Lawrence Livermore National Security, LLC. + */ + +#include +#include +#include +#include +#include +#include +#include + +static void +seek_data(int fd, off_t offset, off_t expected) +{ + off_t data_offset = lseek(fd, offset, SEEK_DATA); + if (data_offset != expected) { + fprintf(stderr, "lseek(fd, %d, SEEK_DATA) = %d (expected %d)\n", + (int)offset, (int)data_offset, (int)expected); + exit(2); + } +} + +static void +seek_hole(int fd, off_t offset, off_t expected) +{ + off_t hole_offset = lseek(fd, offset, SEEK_HOLE); + if (hole_offset != expected) { + fprintf(stderr, "lseek(fd, %d, SEEK_HOLE) = %d (expected %d)\n", + (int)offset, (int)hole_offset, (int)expected); + exit(2); + } +} + +int +main(int argc, char **argv) +{ + char *execname = argv[0]; + char *file_path = argv[1]; + char *buf = NULL; + int err; + + if (argc != 4) { + (void) printf("usage: %s " + "\n", argv[0]); + exit(1); + } + + int fd = open(file_path, O_RDWR | O_CREAT, 0666); + if (fd == -1) { + (void) fprintf(stderr, "%s: %s: ", execname, file_path); + perror("open"); + exit(2); + } + + off_t file_size = atoi(argv[2]); + off_t block_size = atoi(argv[3]); + + if (block_size * 2 > file_size) { + (void) fprintf(stderr, "file size must be at least " + "double the block size\n"); + exit(2); + } + + err = ftruncate(fd, file_size); + if (err == -1) { + perror("ftruncate"); + exit(2); + } + + if ((buf = mmap(NULL, file_size, PROT_READ | PROT_WRITE, + MAP_SHARED, fd, 0)) == MAP_FAILED) { + perror("mmap"); + exit(2); + } + + /* Verify the file is sparse and reports no data. */ + seek_data(fd, 0, -1); + + /* Verify the file is reported as a hole. */ + seek_hole(fd, 0, 0); + + /* Verify search beyond end of file is an error. */ + seek_data(fd, 2 * file_size, -1); + seek_hole(fd, 2 * file_size, -1); + + /* Dirty the first byte. */ + memset(buf, 'a', 1); + seek_data(fd, 0, 0); + seek_data(fd, block_size, -1); + seek_hole(fd, 0, block_size); + seek_hole(fd, block_size, block_size); + + /* Dirty the first half of the file. */ + memset(buf, 'b', file_size / 2); + seek_data(fd, 0, 0); + seek_data(fd, block_size, block_size); + seek_hole(fd, 0, P2ROUNDUP(file_size / 2, block_size)); + seek_hole(fd, block_size, P2ROUNDUP(file_size / 2, block_size)); + + /* Dirty the whole file. */ + memset(buf, 'c', file_size); + seek_data(fd, 0, 0); + seek_data(fd, file_size * 3 / 4, + P2ROUNDUP(file_size * 3 / 4, block_size)); + seek_hole(fd, 0, file_size); + seek_hole(fd, file_size / 2, file_size); + + /* Punch a hole (required compression be enabled). */ + memset(buf + block_size, 0, block_size); + seek_data(fd, 0, 0); + seek_data(fd, block_size, 2 * block_size); + seek_hole(fd, 0, block_size); + seek_hole(fd, block_size, block_size); + seek_hole(fd, 2 * block_size, file_size); + + err = munmap(buf, file_size); + if (err == -1) { + perror("munmap"); + exit(2); + } + + close(fd); + + return (0); +} diff --git a/tests/zfs-tests/include/commands.cfg b/tests/zfs-tests/include/commands.cfg index 1ec73f25bae..4497a6248b4 100644 --- a/tests/zfs-tests/include/commands.cfg +++ b/tests/zfs-tests/include/commands.cfg @@ -209,6 +209,7 @@ export ZFSTEST_FILES='badsend mktree mmap_exec mmap_libaio + mmap_seek mmapwrite nvlist_to_lua randfree_file diff --git a/tests/zfs-tests/include/tunables.cfg b/tests/zfs-tests/include/tunables.cfg index 56d430a3987..fff43e46916 100644 --- a/tests/zfs-tests/include/tunables.cfg +++ b/tests/zfs-tests/include/tunables.cfg @@ -33,6 +33,7 @@ DEADMAN_FAILMODE deadman.failmode zfs_deadman_failmode DEADMAN_SYNCTIME_MS deadman.synctime_ms zfs_deadman_synctime_ms DEADMAN_ZIOTIME_MS deadman.ziotime_ms zfs_deadman_ziotime_ms DISABLE_IVSET_GUID_CHECK disable_ivset_guid_check zfs_disable_ivset_guid_check +DMU_OFFSET_NEXT_SYNC dmu_offset_next_sync zfs_dmu_offset_next_sync INITIALIZE_CHUNK_SIZE initialize_chunk_size zfs_initialize_chunk_size INITIALIZE_VALUE initialize_value zfs_initialize_value KEEP_LOG_SPACEMAPS_AT_EXPORT keep_log_spacemaps_at_export zfs_keep_log_spacemaps_at_export diff --git a/tests/zfs-tests/tests/functional/mmap/Makefile.am b/tests/zfs-tests/tests/functional/mmap/Makefile.am index 2adc398b8c0..b26791ee7ce 100644 --- a/tests/zfs-tests/tests/functional/mmap/Makefile.am +++ b/tests/zfs-tests/tests/functional/mmap/Makefile.am @@ -4,7 +4,8 @@ dist_pkgdata_SCRIPTS = \ cleanup.ksh \ mmap_read_001_pos.ksh \ mmap_write_001_pos.ksh \ - mmap_libaio_001_pos.ksh + mmap_libaio_001_pos.ksh \ + mmap_seek_001_pos.ksh dist_pkgdata_DATA = \ mmap.cfg diff --git a/tests/zfs-tests/tests/functional/mmap/mmap_seek_001_pos.ksh b/tests/zfs-tests/tests/functional/mmap/mmap_seek_001_pos.ksh new file mode 100755 index 00000000000..6188549ad8d --- /dev/null +++ b/tests/zfs-tests/tests/functional/mmap/mmap_seek_001_pos.ksh @@ -0,0 +1,67 @@ +#!/bin/ksh -p +# +# CDDL HEADER START +# +# The contents of this file are subject to the terms of the +# Common Development and Distribution License (the "License"). +# You may not use this file except in compliance with the License. +# +# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE +# or http://www.opensolaris.org/os/licensing. +# See the License for the specific language governing permissions +# and limitations under the License. +# +# When distributing Covered Code, include this CDDL HEADER in each +# file and include the License file at usr/src/OPENSOLARIS.LICENSE. +# If applicable, add the following below this CDDL HEADER, with the +# fields enclosed by brackets "[]" replaced with your own identifying +# information: Portions Copyright [yyyy] [name of copyright owner] +# +# CDDL HEADER END +# + +# +# Copyright (c) 2021 by Lawrence Livermore National Security, LLC. +# + +. $STF_SUITE/include/libtest.shlib +. $STF_SUITE/tests/functional/mmap/mmap.cfg + +# +# DESCRIPTION: +# lseek() data/holes for an mmap()'d file. +# +# STRATEGY: +# 1. Enable compression and hole reporting for dirty files. +# 2. Call mmap_seek binary test case for various record sizes. +# + +verify_runnable "global" + +function cleanup +{ + log_must zfs set compression=off $TESTPOOL/$TESTFS + log_must zfs set recordsize=128k $TESTPOOL/$TESTFS + log_must rm -f $TESTDIR/test-mmap-file + log_must set_tunable64 DMU_OFFSET_NEXT_SYNC $dmu_offset_next_sync +} + +log_assert "lseek() data/holes for an mmap()'d file." + +log_onexit cleanup + +# Enable hole reporting for dirty files. +typeset dmu_offset_next_sync=$(get_tunable DMU_OFFSET_NEXT_SYNC) +log_must set_tunable64 DMU_OFFSET_NEXT_SYNC 1 + +# Compression must be enabled to convert zero'd blocks to holes. +# This behavior is checked by the mmap_seek test. +log_must zfs set compression=on $TESTPOOL/$TESTFS + +for bs in 4096 8192 16384 32768 65536 131072; do + log_must zfs set recordsize=$bs $TESTPOOL/$TESTFS + log_must mmap_seek $TESTDIR/test-mmap-file $((1024*1024)) $bs + log_must rm $TESTDIR/test-mmap-file +done + +log_pass "lseek() data/holes for an mmap()'d file succeeded."