Fix mmap / libaio deadlock
authorBrian Behlendorf <behlendorf1@llnl.gov>
Wed, 28 Mar 2018 17:19:22 +0000 (10:19 -0700)
committerGitHub <noreply@github.com>
Wed, 28 Mar 2018 17:19:22 +0000 (10:19 -0700)
Calling uiomove() in mappedread() under the page lock can result
in a deadlock if the user space page needs to be faulted in.

Resolve the issue by dropping the page lock before the uiomove().
The inode range lock protects against concurrent updates via
zfs_read() and zfs_write().

Reviewed-by: Albert Lee <trisk@forkgnu.org>
Reviewed-by: Chunwei Chen <david.chen@nutanix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7335
Closes #7339

14 files changed:
config/user-libaio.m4 [new file with mode: 0644]
config/user.m4
config/zfs-build.m4
configure.ac
module/zfs/zfs_vnops.c
rpm/generic/zfs.spec.in
tests/runfiles/linux.run
tests/zfs-tests/cmd/Makefile.am
tests/zfs-tests/cmd/mmap_libaio/.gitignore [new file with mode: 0644]
tests/zfs-tests/cmd/mmap_libaio/Makefile.am [new file with mode: 0644]
tests/zfs-tests/cmd/mmap_libaio/mmap_libaio.c [new file with mode: 0644]
tests/zfs-tests/include/commands.cfg
tests/zfs-tests/tests/functional/mmap/Makefile.am
tests/zfs-tests/tests/functional/mmap/mmap_libaio_001_pos.ksh [new file with mode: 0755]

diff --git a/config/user-libaio.m4 b/config/user-libaio.m4
new file mode 100644 (file)
index 0000000..d7a7cb5
--- /dev/null
@@ -0,0 +1,14 @@
+dnl #
+dnl # Check for libaio - only used for libaiot test cases.
+dnl #
+AC_DEFUN([ZFS_AC_CONFIG_USER_LIBAIO], [
+       LIBAIO=
+
+       AC_CHECK_HEADER([libaio.h], [
+           user_libaio=yes
+           AC_SUBST([LIBAIO], ["-laio"])
+           AC_DEFINE([HAVE_LIBAIO], 1, [Define if you have libaio])
+       ], [
+           user_libaio=no
+       ])
+])
index f5e5e9acd4af31a2610e1991928556b4c8295501..f2f366e3c9ff3a734e43291eeb0bed7055e01c6b 100644 (file)
@@ -13,6 +13,7 @@ AC_DEFUN([ZFS_AC_CONFIG_USER], [
        ZFS_AC_CONFIG_USER_LIBBLKID
        ZFS_AC_CONFIG_USER_LIBUDEV
        ZFS_AC_CONFIG_USER_LIBSSL
+       ZFS_AC_CONFIG_USER_LIBAIO
        ZFS_AC_CONFIG_USER_RUNSTATEDIR
        ZFS_AC_CONFIG_USER_MAKEDEV_IN_SYSMACROS
        ZFS_AC_CONFIG_USER_MAKEDEV_IN_MKDEV
index 818e999825b7a13a38e08a167968c52ff088e560..d9b052e27760ab8c754faef84aa3194b7491c524 100644 (file)
@@ -140,11 +140,11 @@ AC_DEFUN([ZFS_AC_CONFIG], [
        AM_CONDITIONAL([CONFIG_KERNEL],
            [test "$ZFS_CONFIG" = kernel -o "$ZFS_CONFIG" = all] &&
            [test "x$enable_linux_builtin" != xyes ])
-       AM_CONDITIONAL([WANT_DEVNAME2DEVID],
-           [test "x$user_libudev" = xyes ])
        AM_CONDITIONAL([CONFIG_QAT],
            [test "$ZFS_CONFIG" = kernel -o "$ZFS_CONFIG" = all] &&
            [test "x$qatsrc" != x ])
+       AM_CONDITIONAL([WANT_DEVNAME2DEVID], [test "x$user_libudev" = xyes ])
+       AM_CONDITIONAL([WANT_MMAP_LIBAIO], [test "x$user_libaio" = xyes ])
 ])
 
 dnl #
index c5585ea40dd99c01f8e1db3a6db33ea236d69a86..5a84ffcbf40c093d9bf29fab24e6875ccc852472 100644 (file)
@@ -165,6 +165,7 @@ AC_CONFIG_FILES([
        tests/zfs-tests/cmd/mkfiles/Makefile
        tests/zfs-tests/cmd/mktree/Makefile
        tests/zfs-tests/cmd/mmap_exec/Makefile
+       tests/zfs-tests/cmd/mmap_libaio/Makefile
        tests/zfs-tests/cmd/mmapwrite/Makefile
        tests/zfs-tests/cmd/nvlist_to_lua/Makefile
        tests/zfs-tests/cmd/randfree_file/Makefile
index a2d7d7b24da6ff89bb4104916b01a249a555f7fd..14caa80e542f3a0108c355cc45466bbafce2207b 100644 (file)
@@ -400,6 +400,7 @@ mappedread(struct inode *ip, int nbytes, uio_t *uio)
                pp = find_lock_page(mp, start >> PAGE_SHIFT);
                if (pp) {
                        ASSERT(PageUptodate(pp));
+                       unlock_page(pp);
 
                        pb = kmap(pp);
                        error = uiomove(pb + off, bytes, UIO_READ, uio);
@@ -409,7 +410,6 @@ mappedread(struct inode *ip, int nbytes, uio_t *uio)
                                flush_dcache_page(pp);
 
                        mark_page_accessed(pp);
-                       unlock_page(pp);
                        put_page(pp);
                } else {
                        error = dmu_read_uio_dbuf(sa_get_db(zp->z_sa_hdl),
index 52dc80a4ef95be85c7005c90ce3ab1663c8898e4..beb7671a10fe9fa3305da94e47b79fc59bb1db12 100644 (file)
@@ -189,6 +189,7 @@ Requires:       fio
 Requires:       acl
 Requires:       sudo
 Requires:       sysstat
+Requires:      libaio
 AutoReqProv:    no
 
 %description test
index 7c2ca84bffd101f2a69e7e51365745b9a59f8045..1852937164cacbd3c35c0d1eeb29920257395c60 100644 (file)
@@ -572,7 +572,7 @@ 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_libaio_001_pos']
 tags = ['functional', 'mmap']
 
 [tests/functional/mmp]
index bc19f184c49631089f1b09f7fc944c77b506fe4a..0673fcbf62179a2ea1d679203eb8156c81ff6a23 100644 (file)
@@ -14,6 +14,7 @@ SUBDIRS = \
        mkfiles \
        mktree \
        mmap_exec \
+       mmap_libaio \
        mmapwrite \
        nvlist_to_lua \
        randfree_file \
diff --git a/tests/zfs-tests/cmd/mmap_libaio/.gitignore b/tests/zfs-tests/cmd/mmap_libaio/.gitignore
new file mode 100644 (file)
index 0000000..792c8d3
--- /dev/null
@@ -0,0 +1 @@
+/mmap_libaio
diff --git a/tests/zfs-tests/cmd/mmap_libaio/Makefile.am b/tests/zfs-tests/cmd/mmap_libaio/Makefile.am
new file mode 100644 (file)
index 0000000..67d0f0e
--- /dev/null
@@ -0,0 +1,9 @@
+include $(top_srcdir)/config/Rules.am
+
+pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/bin
+
+if WANT_MMAP_LIBAIO
+pkgexec_PROGRAMS = mmap_libaio
+mmap_libaio_SOURCES = mmap_libaio.c
+mmap_libaio_LDADD = $(LIBAIO)
+endif
diff --git a/tests/zfs-tests/cmd/mmap_libaio/mmap_libaio.c b/tests/zfs-tests/cmd/mmap_libaio/mmap_libaio.c
new file mode 100644 (file)
index 0000000..21119eb
--- /dev/null
@@ -0,0 +1,88 @@
+/*
+ * 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 2018 Canonical.  All rights reserved.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <libaio.h>
+#include <err.h>
+
+io_context_t io_ctx;
+
+static void
+do_sync_io(struct iocb *iocb)
+{
+       struct io_event event;
+       struct iocb *iocbs[] = { iocb };
+       struct timespec ts = { 30, 0 };
+
+       if (io_submit(io_ctx, 1, iocbs) != 1)
+               err(1, "io_submit failed");
+
+       if (io_getevents(io_ctx, 0, 1, &event, &ts) != 1)
+               err(1, "io_getevents failed");
+}
+
+int
+main(int argc, char **argv)
+{
+       char *buf;
+       int page_size = getpagesize();
+       int buf_size = strtol(argv[2], NULL, 0);
+       int rwfd;
+       struct iocb iocb;
+
+       if (io_queue_init(1024, &io_ctx))
+               err(1, "io_queue_init failed");
+
+       rwfd = open(argv[1], O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+       if (rwfd < 0)
+               err(1, "open failed");
+
+       if (ftruncate(rwfd, buf_size) < 0)
+               err(1, "ftruncate failed");
+
+       buf = mmap(0, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rwfd, 0);
+       if (buf == MAP_FAILED)
+               err(1, "mmap failed");
+
+       (void) io_prep_pwrite(&iocb, rwfd, buf, buf_size, 0);
+       do_sync_io(&iocb);
+
+       (void) io_prep_pread(&iocb, rwfd, buf, buf_size, 0);
+       do_sync_io(&iocb);
+
+       if (close(rwfd))
+               err(1, "close failed");
+
+       if (io_queue_release(io_ctx) != 0)
+               err(1, "io_queue_release failed");
+
+       return (0);
+}
index 64d6ad5d727db9384710ad2d27e980425d4ec986..2a6c3b13d2faf969c93a203d259a4bf5abc79216 100644 (file)
@@ -164,6 +164,7 @@ export ZFSTEST_FILES='chg_usr_exec
     mkfiles
     mktree
     mmap_exec
+    mmap_libaio
     mmapwrite
     nvlist_to_lua
     randfree_file
index cb444ec379d0ab11ab1a02021a7883fd69f83152..4e1db6041f41d7cdc2897073b71a878a9d9684a9 100644 (file)
@@ -4,4 +4,5 @@ dist_pkgdata_SCRIPTS = \
        cleanup.ksh \
        mmap.cfg \
        mmap_read_001_pos.ksh \
-       mmap_write_001_pos.ksh
+       mmap_write_001_pos.ksh \
+       mmap_libaio_001_pos.ksh
diff --git a/tests/zfs-tests/tests/functional/mmap/mmap_libaio_001_pos.ksh b/tests/zfs-tests/tests/functional/mmap/mmap_libaio_001_pos.ksh
new file mode 100755 (executable)
index 0000000..36a7e76
--- /dev/null
@@ -0,0 +1,61 @@
+#!/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 2018 Canonical.  All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/mmap/mmap.cfg
+
+#
+# DESCRIPTION:
+# Verify libaio functions correctly with mmap()'d files.
+#
+# STRATEGY:
+# 1. Call mmap_libaio binary
+# 2. Verify the file exists and is the expected size
+# 3. Verify the filesystem is intact and not hung in any way
+#
+
+verify_runnable "global"
+
+log_assert "verify mmap'd pages work with libaio"
+
+# mmap_libaio is built when the libaio-devel package is installed.
+if ! which mmap_libaio; then
+       log_unsupported "This test requires mmap_libaio."
+fi
+
+log_must chmod 777 $TESTDIR
+
+for size in 512 4096 8192; do
+       log_mustnot stat $TESTDIR/test-libaio-file
+       log_must mmap_libaio $TESTDIR/test-libaio-file $size
+       log_must verify_eq $(stat --format=%s $TESTDIR/test-libaio-file) $size
+       log_must rm $TESTDIR/test-libaio-file
+done
+
+typeset dir=$(get_device_dir $DISKS)
+verify_filesys "$TESTPOOL" "$TESTPOOL/$TESTFS" "$dir"
+
+log_pass "mmap'd pages work with libaio"