On Tue, Oct 10, 2017 at 10:02:09AM -0400, Brian Foster wrote: > On Tue, Oct 10, 2017 at 03:42:08PM +0800, Eryu Guan wrote: > > From: Zheng Liu <wenqing.lz@xxxxxxxxxx> > > > > In this commit a new test case is added to test that i_size races > > don't occur under dio reads/writes. We add a program in /src dir, > > which has a writer to issue some append dio writes. Meanwhile it > > has a reader in this test to do some dio reads. As we expect, > > reader should read nothing or data with 'a'. But it might read some > > data with '0'. > > > > The bug can be reproduced by this test case [1]. > > > > 1. http://patchwork.ozlabs.org/patch/311761/ > > > > This ostensibly tests commit: > > 9fe55eea7 Fix race when checking i_size on direct i/o read > > > > Update by Eric Sandeen: > > - update to recent xfstests > > - update commit log > > > > Update by Eryu Guan: > > - add aio-dio support to the test and add 'aio' group > > - add ability to test different alignments > > - move test from src/ to src/aio-dio-regress/ > > - add .gitignore entry > > - rebase against latest xfstests with various minor fixes & cleanups > > - update commit log > > > > Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx> > > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > > Signed-off-by: Eryu Guan <eguan@xxxxxxxxxx> > > --- > > v2: > > - start background reader in a thread first then start writer only after > > reader starts issuing reads > > > > Confirmed that v2 still reproduces the bug reliably with unpatched > > kernel and test passed with v4.14-rc3 kernel. > > > > Eric's original post > > http://www.spinics.net/lists/fstests/msg06978.html > > > > .gitignore | 1 + > > .../aio-dio-append-write-read-race.c | 230 +++++++++++++++++++++ > > tests/generic/464 | 75 +++++++ > > tests/generic/464.out | 3 + > > tests/generic/group | 1 + > > 5 files changed, 310 insertions(+) > > create mode 100644 src/aio-dio-regress/aio-dio-append-write-read-race.c > > create mode 100755 tests/generic/464 > > create mode 100644 tests/generic/464.out > > > ... > > diff --git a/src/aio-dio-regress/aio-dio-append-write-read-race.c b/src/aio-dio-regress/aio-dio-append-write-read-race.c > > new file mode 100644 > > index 000000000000..2956599c1474 > > --- /dev/null > > +++ b/src/aio-dio-regress/aio-dio-append-write-read-race.c > > @@ -0,0 +1,230 @@ > ... > > +static void *reader(void *arg) > > +{ > > + struct io_data *data = (struct io_data *)arg; > > + int ret; > > + > > + memset(data->buf, 'b', data->blksize); > > + do { > > + ret = pread(data->fd, data->buf, data->blksize, data->offset); > > + if (ret < 0) > > + perror("read file"); > > + if (!reader_ready) > > + reader_ready = 1; > > Hmm, this looks potentially racy with the associated reader_ready = 0 > down in writer(). Once writer() executes, suppose it resets > reader_read, then reader() reads the data, resets reader_ready = 1 and > exits. ISTM reader_ready would incorrectly == 1 the next time around the > loop. You're right, that's possible. > > I think it's fine to set reader_ready = 1 after the memset(). Then just > reinit it to 0 in main() before the reader thread is started (instead of > down in writer())..? Yeah, this looks much clearer, I'll send v3 shortly. Thanks a lot! Eryu > > Brian > > > + } while (ret <= 0); > > + > > + return NULL; > > +} > > + > > +static void *writer(struct io_data *data) > > +{ > > + int ret; > > + > > + while (!reader_ready) > > + usleep(1); > > + > > + if (data->use_aio) { > > + struct io_context *ctx = NULL; > > + struct io_event evs[1]; > > + struct iocb iocb; > > + struct iocb *iocbs[] = { &iocb }; > > + > > + ret = io_setup(1, &ctx); > > + if (ret) { > > + fprintf(stderr, "error %s during io_setup\n", > > + strerror(ret)); > > + return NULL; > > + } > > + io_prep_pwrite(&iocb, data->fd, data->buf, data->blksize, data->offset); > > + ret = io_submit(ctx, 1, iocbs); > > + if (ret != 1) { > > + fprintf(stderr, "error %s during io_submit\n", > > + strerror(ret)); > > + return NULL; > > + } > > + ret = io_getevents(ctx, 1, 1, evs, NULL); > > + if (ret != 1) { > > + fprintf(stderr, "error %s during io_getevents\n", > > + strerror(ret)); > > + return NULL; > > + } > > + } else { > > + ret = pwrite(data->fd, data->buf, data->blksize, data->offset); > > + if (ret < 0) > > + perror("write file failed"); > > + } > > + > > + reader_ready = 0; > > + return NULL; > > +} > > + > > +int main(int argc, char *argv[]) > > +{ > > + pthread_t tid; > > + struct io_data wdata; > > + struct io_data rdata; > > + size_t max_blocks = 128; /* 128 */ > > + size_t blksize = 1 * 1024 * 1024; /* 1M */ > > + char *rbuf = NULL, *wbuf = NULL; > > + int rfd = 0, wfd = 0; > > + int i, j, c; > > + int use_aio = 1; > > + int ret = 0; > > + int io_align = 4096; > > + char *prog; > > + char *testfile; > > + > > + > > + prog = basename(argv[0]); > > + > > + while ((c = getopt(argc, argv, "a:d")) != -1) { > > + switch (c) { > > + case 'a': > > + io_align = strtol(optarg, NULL, 0); > > + break; > > + case 'd': > > + use_aio = 0; > > + break; > > + default: > > + usage(prog); > > + } > > + } > > + if (optind != argc - 1) > > + usage(prog); > > + testfile = argv[optind]; > > + > > + wfd = open(testfile, O_CREAT|O_DIRECT|O_WRONLY|O_TRUNC, 0644); > > + if (wfd < 0) { > > + perror("open for write"); > > + exit(1); > > + } > > + > > + rfd = open(testfile, O_DIRECT|O_RDONLY, 0644); > > + if (rfd < 0) { > > + perror("open for read"); > > + ret = 1; > > + goto err; > > + } > > + > > + ret = posix_memalign((void **)&wbuf, io_align, blksize); > > + if (ret) { > > + fprintf(stderr, "failed to alloc memory: %s\n", strerror(ret)); > > + ret = 1; > > + goto err; > > + } > > + > > + ret = posix_memalign((void **)&rbuf, io_align, blksize); > > + if (ret) { > > + fprintf(stderr, "failed to alloc memory: %s\n", strerror(ret)); > > + ret = 1; > > + goto err; > > + } > > + > > + memset(wbuf, 'a', blksize); > > + wdata.fd = wfd; > > + wdata.blksize = blksize; > > + wdata.buf = wbuf; > > + wdata.use_aio = use_aio; > > + rdata.fd = rfd; > > + rdata.blksize = blksize; > > + rdata.buf = rbuf; > > + > > + for (i = 0; i < max_blocks; i++) { > > + wdata.offset = rdata.offset = i * blksize; > > + > > + ret = pthread_create(&tid, NULL, reader, &rdata); > > + if (ret) { > > + fprintf(stderr, "create reader thread failed: %s\n", > > + strerror(ret)); > > + ret = 1; > > + goto err; > > + } > > + > > + writer(&wdata); > > + > > + ret = pthread_join(tid, NULL); > > + if (ret) { > > + fprintf(stderr, "pthread join reader failed: %s\n", > > + strerror(ret)); > > + ret = 1; > > + goto err; > > + } > > + > > + for (j = 0; j < blksize; j++) { > > + if (rdata.buf[j] != 'a') { > > + fprintf(stderr, "encounter an error: " > > + "block %d offset %d, content %x\n", > > + i, j, rbuf[j]); > > + ret = 1; > > + goto err; > > + } > > + } > > + } > > + > > +err: > > + if (rfd) > > + close(rfd); > > + if (wfd) > > + close(wfd); > > + if (rbuf) > > + free(rbuf); > > + if (wbuf) > > + free(wbuf); > > + > > + exit(ret); > > +} > > diff --git a/tests/generic/464 b/tests/generic/464 > > new file mode 100755 > > index 000000000000..b0423c91a7cf > > --- /dev/null > > +++ b/tests/generic/464 > > @@ -0,0 +1,75 @@ > > +#! /bin/bash > > +# FS QA Test No. 464 > > +# > > +# Test i_size is updated properly under dio read/write > > +# > > +#----------------------------------------------------------------------- > > +# Copyright (c) 2013 Alibaba Group. All Rights Reserved. > > +# Copyright (c) 2017 Red Hat Inc. All Rights Reserved. > > +# > > +# This program is free software; you can redistribute it and/or > > +# modify it under the terms of the GNU General Public License as > > +# published by the Free Software Foundation. > > +# > > +# This program is distributed in the hope that it would be useful, > > +# but WITHOUT ANY WARRANTY; without even the implied warranty of > > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > +# GNU General Public License for more details. > > +# > > +# You should have received a copy of the GNU General Public License > > +# along with this program; if not, write the Free Software Foundation, > > +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA > > +#----------------------------------------------------------------------- > > +# > > + > > +seq=`basename $0` > > +seqres=$RESULT_DIR/$seq > > +echo "QA output created by $seq" > > + > > +here=`pwd` > > +tmp=/tmp/$$ > > +status=1 # failure is the default! > > +trap "_cleanup; exit \$status" 0 1 2 3 15 > > + > > +_cleanup() > > +{ > > + cd / > > + rm -f $tmp.* $testfile.* > > +} > > + > > +# get standard environment, filters and checks > > +. ./common/rc > > +. ./common/filter > > + > > +# real QA test starts here > > +_supported_fs generic > > +_supported_os Linux > > + > > +_require_aiodio aio-dio-append-write-read-race > > +_require_test_program "feature" > > + > > +testfile=$TEST_DIR/$seq.$$ > > +min_dio_align=`_min_dio_alignment $TEST_DEV` > > +page_size=`$here/src/feature -s` > > + > > +rm -f $seqres.full > > + > > +echo "non-aio dio test" > > +align=$min_dio_align > > +while [ $align -le $page_size ]; do > > + echo "$AIO_TEST -a $align -d $testfile.$align" >> $seqres.full > > + $AIO_TEST -a $align -d $testfile.$align 2>&1 | tee -a $seqres.full > > + align=$((align * 2)) > > +done > > + > > +echo "aio-dio test" > > +align=$min_dio_align > > +while [ $align -le $page_size ]; do > > + echo "$AIO_TEST -a $align $testfile.$align" >> $seqres.full > > + $AIO_TEST -a $align $testfile.$align 2>&1 | tee -a $seqres.full > > + align=$((align * 2)) > > +done > > + > > +# success, all done > > +status=0 > > +exit > > diff --git a/tests/generic/464.out b/tests/generic/464.out > > new file mode 100644 > > index 000000000000..14e66fe7d778 > > --- /dev/null > > +++ b/tests/generic/464.out > > @@ -0,0 +1,3 @@ > > +QA output created by 464 > > +non-aio dio test > > +aio-dio test > > diff --git a/tests/generic/group b/tests/generic/group > > index 9f173e7a63c9..556add16286b 100644 > > --- a/tests/generic/group > > +++ b/tests/generic/group > > @@ -466,3 +466,4 @@ > > 461 auto shutdown stress > > 462 auto quick dax > > 463 auto rw > > +464 auto rw quick aio > > -- > > 2.13.6 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe fstests" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
