| Message ID | 1493055891-8814-1-git-send-email-zlang@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 25, 2017 at 01:44:51AM +0800, Zorro Lang wrote: > It's possible for post-eof blocks to end up being used for direct I/O > writes. dio write performs an upfront unwritten extent allocation, sends > the dio and then updates the inode size (if necessary) on write > completion. If a file release occurs while a file extending dio write is > in flight, it is possible to mistake the post-eof blocks for speculative > preallocation and incorrectly truncate them from the inode. This means > that the resulting dio write completion can discover a hole and allocate > new blocks rather than perform unwritten extent conversion. > > A kernel warning can be reproduced by generic/299 on XFS: > XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, \ > file: fs/xfs//xfs_trans.c, line: 309 > > The root cause is that xfs_free_eofblocks() uses i_size to truncate > post-eof blocks from the inode, but async, file extending direct writes > do not update i_size until write completion, long after inode locks are > dropped. Therefore, xfs_free_eofblocks() effectively truncates the inode > to the incorrect size. > > Besides reproduce above kernel warning, the verification of written > data is an important distinction between this test and generic/299. > For cover this filesystem corruption testing, write this new case to > check data integrality manually, not only depend on a kernel warning. > > To increase the test stress of aio-dio-eof-race, add two arguments to > this source code to change the file size will be written. > > Signed-off-by: Zorro Lang <zlang@redhat.com> > --- > > Hi, > > V2 did below changes: > 1) change aio-dio-eof-race.c, add two arguments to change the file size > and buffer size. > 2) change fs size from 1G to 256M > 3) move open/close loop before $AIO_TEST > 4) use new aio-dio-eof-race arguments, and use cpu number to decide the > file size. > 5) change open/close operation from "cat" to "xfs_io -c open" > > Thanks, > Zorro > > src/aio-dio-regress/aio-dio-eof-race.c | 74 ++++++++++++++++++++------- > tests/generic/426 | 91 ++++++++++++++++++++++++++++++++++ > tests/generic/426.out | 2 + > tests/generic/group | 1 + > 4 files changed, 151 insertions(+), 17 deletions(-) > create mode 100755 tests/generic/426 > create mode 100644 tests/generic/426.out > > diff --git a/src/aio-dio-regress/aio-dio-eof-race.c b/src/aio-dio-regress/aio-dio-eof-race.c > index 79fd928..7b2c26f 100644 > --- a/src/aio-dio-regress/aio-dio-eof-race.c > +++ b/src/aio-dio-regress/aio-dio-eof-race.c > @@ -29,11 +29,21 @@ > > #include <libaio.h> > > -/* Sized to allow 4 x 512 AIOs */ > -#define BUF_SIZE 2048 > +unsigned long buf_size = 0; > +unsigned long size_MB = 0; > #define IO_PATTERN 0xab > > void > +usage(char *progname) > +{ > + fprintf(stderr, "usage: %s [-s filesize] [-b bufsize] filename\n" > + "\t-s filesize: specify the minimum file size" > + "\t-b bufsize: buffer size", > + progname); > + exit(1); > +} > + > +void > dump_buffer( > void *buf, > off64_t offset, > @@ -83,24 +93,54 @@ int main(int argc, char *argv[]) > struct iocb *iocbs[] = { &iocb1, &iocb2, &iocb3, &iocb4 }; > void *buf; > struct stat statbuf; > - char cmp_buf[BUF_SIZE]; > int fd, err = 0; > off_t eof; > + int c; > + char *cmp_buf = NULL; > + char *filename = NULL; > + > + while ((c = getopt(argc, argv, "s:b:")) != -1) { > + char *endp; > + > + switch (c) { > + case 's': /* XXX MB size will be extended */ > + size_MB = strtol(optarg, &endp, 0); > + break; > + case 'b': /* buffer size */ > + buf_size = strtol(optarg, &endp, 0); > + break; > + default: > + usage(argv[0]); > + } > + } > + > + if (size_MB == 0) /* default size is 8MB */ > + size_MB = 8; > + if (buf_size < 2048) /* default minimum buffer size is 2048 bytes */ > + buf_size = 2048; > + > + if (optind == argc - 1) > + filename = argv[optind]; > + else > + usage(argv[0]); > + > + > > - fd = open(argv[1], O_DIRECT | O_CREAT | O_TRUNC | O_RDWR, 0600); > + fd = open(filename, O_DIRECT | O_CREAT | O_TRUNC | O_RDWR, 0600); > if (fd == -1) { > perror("open"); > return 1; > } > > - err = posix_memalign(&buf, getpagesize(), BUF_SIZE); > + err = posix_memalign(&buf, getpagesize(), buf_size); > if (err) { > fprintf(stderr, "error %s during %s\n", > strerror(err), > "posix_memalign"); > return 1; > } > - memset(cmp_buf, IO_PATTERN, BUF_SIZE); > + cmp_buf = malloc(buf_size); > + memset(cmp_buf, IO_PATTERN, buf_size); > > err = io_setup(4, &ctx); > if (err) { > @@ -113,8 +153,8 @@ int main(int argc, char *argv[]) > eof = 0; > > /* Keep extending until 8MB (fairly arbitrary) */ > - while (eof < 8 * 1024 * 1024) { > - memset(buf, IO_PATTERN, BUF_SIZE); > + while (eof < size_MB * 1024 * 1024) { > + memset(buf, IO_PATTERN, buf_size); > fstat(fd, &statbuf); > eof = statbuf.st_size; > > @@ -125,10 +165,10 @@ int main(int argc, char *argv[]) > * management and stale block zeroing for races and can lead to > * data corruption when not handled properly. > */ > - io_prep_pwrite(&iocb1, fd, buf, BUF_SIZE/4, eof + 0*BUF_SIZE/4); > - io_prep_pwrite(&iocb2, fd, buf, BUF_SIZE/4, eof + 1*BUF_SIZE/4); > - io_prep_pwrite(&iocb3, fd, buf, BUF_SIZE/4, eof + 2*BUF_SIZE/4); > - io_prep_pwrite(&iocb4, fd, buf, BUF_SIZE/4, eof + 3*BUF_SIZE/4); > + io_prep_pwrite(&iocb1, fd, buf, buf_size/4, eof + 0*buf_size/4); > + io_prep_pwrite(&iocb2, fd, buf, buf_size/4, eof + 1*buf_size/4); > + io_prep_pwrite(&iocb3, fd, buf, buf_size/4, eof + 2*buf_size/4); > + io_prep_pwrite(&iocb4, fd, buf, buf_size/4, eof + 3*buf_size/4); > > err = io_submit(ctx, 4, iocbs); > if (err != 4) { > @@ -150,20 +190,20 @@ int main(int argc, char *argv[]) > * And then read it back. > * > * Using pread to keep it simple, but AIO has the same effect. > - * eof is the prior eof; we just wrote BUF_SIZE more. > + * eof is the prior eof; we just wrote buf_size more. > */ > - if (pread(fd, buf, BUF_SIZE, eof) != BUF_SIZE) { > + if (pread(fd, buf, buf_size, eof) != buf_size) { > perror("pread"); > return 1; > } > > /* > * We launched 4 AIOs which, stitched together, should write > - * a seamless BUF_SIZE worth of IO_PATTERN to the last block. > + * a seamless buf_size worth of IO_PATTERN to the last block. > */ > - if (memcmp(buf, cmp_buf, BUF_SIZE)) { > + if (memcmp(buf, cmp_buf, buf_size)) { > printf("corruption while extending from %ld\n", eof); > - dump_buffer(buf, 0, BUF_SIZE); > + dump_buffer(buf, 0, buf_size); > return 1; > } > } > diff --git a/tests/generic/426 b/tests/generic/426 > new file mode 100755 > index 0000000..8c4e204 > --- /dev/null > +++ b/tests/generic/426 > @@ -0,0 +1,91 @@ > +#! /bin/bash > +# FS QA Test 426 > +# > +# Try to trigger a race of free eofblocks and file extending dio writes. > +# A known bug of XFS has been fixed by "e4229d6 xfs: fix eofblocks race > +# with file extending async dio writes" > +# > +#----------------------------------------------------------------------- > +# 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.* > +} > + > +# get standard environment, filters and checks > +. ./common/rc > +. ./common/filter > + > +# remove previous $seqres.full before test > +rm -f $seqres.full > + > +# real QA test starts here > + > +# Modify as appropriate. > +_supported_fs generic > +_supported_os Linux > +_require_scratch > +_require_aiodio aio-dio-eof-race _require_test_program "feature" > + > +# limit the filesystem size, to save the time of filling filesystem > +_scratch_mkfs_sized $((256 * 1024 * 1024)) >>$seqres.full 2>&1 > +_scratch_mount > + > +# try to write more bytes than filesystem size to fill the filesystem > +$XFS_IO_PROG -f -c "pwrite -S 0x55 0 $((256 * 1024 * 1024 * 2))" \ > + $SCRATCH_MNT/fillfs-$seq 2>/dev/null > +rm -f $SCRATCH_MNT/fillfs-$seq Better to have some comments on this fill-and-remove operation. My two minor nits :) Thanks, Eryu > + > +# open & close the file frequently, to trigger xfs_free_eofblocks > +while true; do > + $XFS_IO_PROG -f -c open $SCRATCH_MNT/tst-aio-dio-eof-race.$seq \ > + >/dev/null 2>&1 > +done & > +open_close_pid=$! > + > +nr_cpu=`$here/src/feature -o` > +fsize=$((nr_cpu * 10)) > +if [ $fsize -gt 200 ]; then > + fsize=200 > +fi > +# start a background aio writer, which does several extending loops > +# internally and check data integrality > +$AIO_TEST -s $fsize -b 65536 $SCRATCH_MNT/tst-aio-dio-eof-race.$seq > +status=$? > + > +kill $open_close_pid > +wait $open_close_pid > +if [ $status -ne 0 ]; then > + od -t x1 $SCRATCH_MNT/tst-aio-dio-eof-race.$seq >> $seqres.full > + exit > +fi > + > +# success, all done > +status=0 > +exit > diff --git a/tests/generic/426.out b/tests/generic/426.out > new file mode 100644 > index 0000000..ad7a01a > --- /dev/null > +++ b/tests/generic/426.out > @@ -0,0 +1,2 @@ > +QA output created by 426 > +Success, all done. > diff --git a/tests/generic/group b/tests/generic/group > index 6d6e4f6..70c36f9 100644 > --- a/tests/generic/group > +++ b/tests/generic/group > @@ -428,3 +428,4 @@ > 423 auto quick > 424 auto quick > 425 auto quick attr > +426 auto aio rw > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe fstests" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Apr 25, 2017 at 01:44:51AM +0800, Zorro Lang wrote: > It's possible for post-eof blocks to end up being used for direct I/O > writes. dio write performs an upfront unwritten extent allocation, sends > the dio and then updates the inode size (if necessary) on write > completion. If a file release occurs while a file extending dio write is > in flight, it is possible to mistake the post-eof blocks for speculative > preallocation and incorrectly truncate them from the inode. This means > that the resulting dio write completion can discover a hole and allocate > new blocks rather than perform unwritten extent conversion. > > A kernel warning can be reproduced by generic/299 on XFS: > XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, \ > file: fs/xfs//xfs_trans.c, line: 309 > > The root cause is that xfs_free_eofblocks() uses i_size to truncate > post-eof blocks from the inode, but async, file extending direct writes > do not update i_size until write completion, long after inode locks are > dropped. Therefore, xfs_free_eofblocks() effectively truncates the inode > to the incorrect size. > > Besides reproduce above kernel warning, the verification of written > data is an important distinction between this test and generic/299. > For cover this filesystem corruption testing, write this new case to > check data integrality manually, not only depend on a kernel warning. > > To increase the test stress of aio-dio-eof-race, add two arguments to > this source code to change the file size will be written. > > Signed-off-by: Zorro Lang <zlang@redhat.com> > --- > > Hi, > > V2 did below changes: > 1) change aio-dio-eof-race.c, add two arguments to change the file size > and buffer size. > 2) change fs size from 1G to 256M > 3) move open/close loop before $AIO_TEST > 4) use new aio-dio-eof-race arguments, and use cpu number to decide the > file size. > 5) change open/close operation from "cat" to "xfs_io -c open" > > Thanks, > Zorro > > src/aio-dio-regress/aio-dio-eof-race.c | 74 ++++++++++++++++++++------- > tests/generic/426 | 91 ++++++++++++++++++++++++++++++++++ > tests/generic/426.out | 2 + > tests/generic/group | 1 + > 4 files changed, 151 insertions(+), 17 deletions(-) > create mode 100755 tests/generic/426 > create mode 100644 tests/generic/426.out > > diff --git a/src/aio-dio-regress/aio-dio-eof-race.c b/src/aio-dio-regress/aio-dio-eof-race.c > index 79fd928..7b2c26f 100644 > --- a/src/aio-dio-regress/aio-dio-eof-race.c > +++ b/src/aio-dio-regress/aio-dio-eof-race.c ... > @@ -113,8 +153,8 @@ int main(int argc, char *argv[]) > eof = 0; > > /* Keep extending until 8MB (fairly arbitrary) */ Nit: stale comment. Otherwise this looks fine to me. Thanks for the test! Reviewed-by: Brian Foster <bfoster@redhat.com> > - while (eof < 8 * 1024 * 1024) { > - memset(buf, IO_PATTERN, BUF_SIZE); > + while (eof < size_MB * 1024 * 1024) { > + memset(buf, IO_PATTERN, buf_size); > fstat(fd, &statbuf); > eof = statbuf.st_size; > > @@ -125,10 +165,10 @@ int main(int argc, char *argv[]) > * management and stale block zeroing for races and can lead to > * data corruption when not handled properly. > */ > - io_prep_pwrite(&iocb1, fd, buf, BUF_SIZE/4, eof + 0*BUF_SIZE/4); > - io_prep_pwrite(&iocb2, fd, buf, BUF_SIZE/4, eof + 1*BUF_SIZE/4); > - io_prep_pwrite(&iocb3, fd, buf, BUF_SIZE/4, eof + 2*BUF_SIZE/4); > - io_prep_pwrite(&iocb4, fd, buf, BUF_SIZE/4, eof + 3*BUF_SIZE/4); > + io_prep_pwrite(&iocb1, fd, buf, buf_size/4, eof + 0*buf_size/4); > + io_prep_pwrite(&iocb2, fd, buf, buf_size/4, eof + 1*buf_size/4); > + io_prep_pwrite(&iocb3, fd, buf, buf_size/4, eof + 2*buf_size/4); > + io_prep_pwrite(&iocb4, fd, buf, buf_size/4, eof + 3*buf_size/4); > > err = io_submit(ctx, 4, iocbs); > if (err != 4) { > @@ -150,20 +190,20 @@ int main(int argc, char *argv[]) > * And then read it back. > * > * Using pread to keep it simple, but AIO has the same effect. > - * eof is the prior eof; we just wrote BUF_SIZE more. > + * eof is the prior eof; we just wrote buf_size more. > */ > - if (pread(fd, buf, BUF_SIZE, eof) != BUF_SIZE) { > + if (pread(fd, buf, buf_size, eof) != buf_size) { > perror("pread"); > return 1; > } > > /* > * We launched 4 AIOs which, stitched together, should write > - * a seamless BUF_SIZE worth of IO_PATTERN to the last block. > + * a seamless buf_size worth of IO_PATTERN to the last block. > */ > - if (memcmp(buf, cmp_buf, BUF_SIZE)) { > + if (memcmp(buf, cmp_buf, buf_size)) { > printf("corruption while extending from %ld\n", eof); > - dump_buffer(buf, 0, BUF_SIZE); > + dump_buffer(buf, 0, buf_size); > return 1; > } > } > diff --git a/tests/generic/426 b/tests/generic/426 > new file mode 100755 > index 0000000..8c4e204 > --- /dev/null > +++ b/tests/generic/426 > @@ -0,0 +1,91 @@ > +#! /bin/bash > +# FS QA Test 426 > +# > +# Try to trigger a race of free eofblocks and file extending dio writes. > +# A known bug of XFS has been fixed by "e4229d6 xfs: fix eofblocks race > +# with file extending async dio writes" > +# > +#----------------------------------------------------------------------- > +# 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.* > +} > + > +# get standard environment, filters and checks > +. ./common/rc > +. ./common/filter > + > +# remove previous $seqres.full before test > +rm -f $seqres.full > + > +# real QA test starts here > + > +# Modify as appropriate. > +_supported_fs generic > +_supported_os Linux > +_require_scratch > +_require_aiodio aio-dio-eof-race > + > +# limit the filesystem size, to save the time of filling filesystem > +_scratch_mkfs_sized $((256 * 1024 * 1024)) >>$seqres.full 2>&1 > +_scratch_mount > + > +# try to write more bytes than filesystem size to fill the filesystem > +$XFS_IO_PROG -f -c "pwrite -S 0x55 0 $((256 * 1024 * 1024 * 2))" \ > + $SCRATCH_MNT/fillfs-$seq 2>/dev/null > +rm -f $SCRATCH_MNT/fillfs-$seq > + > +# open & close the file frequently, to trigger xfs_free_eofblocks > +while true; do > + $XFS_IO_PROG -f -c open $SCRATCH_MNT/tst-aio-dio-eof-race.$seq \ > + >/dev/null 2>&1 > +done & > +open_close_pid=$! > + > +nr_cpu=`$here/src/feature -o` > +fsize=$((nr_cpu * 10)) > +if [ $fsize -gt 200 ]; then > + fsize=200 > +fi > +# start a background aio writer, which does several extending loops > +# internally and check data integrality > +$AIO_TEST -s $fsize -b 65536 $SCRATCH_MNT/tst-aio-dio-eof-race.$seq > +status=$? > + > +kill $open_close_pid > +wait $open_close_pid > +if [ $status -ne 0 ]; then > + od -t x1 $SCRATCH_MNT/tst-aio-dio-eof-race.$seq >> $seqres.full > + exit > +fi > + > +# success, all done > +status=0 > +exit > diff --git a/tests/generic/426.out b/tests/generic/426.out > new file mode 100644 > index 0000000..ad7a01a > --- /dev/null > +++ b/tests/generic/426.out > @@ -0,0 +1,2 @@ > +QA output created by 426 > +Success, all done. > diff --git a/tests/generic/group b/tests/generic/group > index 6d6e4f6..70c36f9 100644 > --- a/tests/generic/group > +++ b/tests/generic/group > @@ -428,3 +428,4 @@ > 423 auto quick > 424 auto quick > 425 auto quick attr > +426 auto aio rw > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe fstests" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/src/aio-dio-regress/aio-dio-eof-race.c b/src/aio-dio-regress/aio-dio-eof-race.c index 79fd928..7b2c26f 100644 --- a/src/aio-dio-regress/aio-dio-eof-race.c +++ b/src/aio-dio-regress/aio-dio-eof-race.c @@ -29,11 +29,21 @@ #include <libaio.h> -/* Sized to allow 4 x 512 AIOs */ -#define BUF_SIZE 2048 +unsigned long buf_size = 0; +unsigned long size_MB = 0; #define IO_PATTERN 0xab void +usage(char *progname) +{ + fprintf(stderr, "usage: %s [-s filesize] [-b bufsize] filename\n" + "\t-s filesize: specify the minimum file size" + "\t-b bufsize: buffer size", + progname); + exit(1); +} + +void dump_buffer( void *buf, off64_t offset, @@ -83,24 +93,54 @@ int main(int argc, char *argv[]) struct iocb *iocbs[] = { &iocb1, &iocb2, &iocb3, &iocb4 }; void *buf; struct stat statbuf; - char cmp_buf[BUF_SIZE]; int fd, err = 0; off_t eof; + int c; + char *cmp_buf = NULL; + char *filename = NULL; + + while ((c = getopt(argc, argv, "s:b:")) != -1) { + char *endp; + + switch (c) { + case 's': /* XXX MB size will be extended */ + size_MB = strtol(optarg, &endp, 0); + break; + case 'b': /* buffer size */ + buf_size = strtol(optarg, &endp, 0); + break; + default: + usage(argv[0]); + } + } + + if (size_MB == 0) /* default size is 8MB */ + size_MB = 8; + if (buf_size < 2048) /* default minimum buffer size is 2048 bytes */ + buf_size = 2048; + + if (optind == argc - 1) + filename = argv[optind]; + else + usage(argv[0]); + + - fd = open(argv[1], O_DIRECT | O_CREAT | O_TRUNC | O_RDWR, 0600); + fd = open(filename, O_DIRECT | O_CREAT | O_TRUNC | O_RDWR, 0600); if (fd == -1) { perror("open"); return 1; } - err = posix_memalign(&buf, getpagesize(), BUF_SIZE); + err = posix_memalign(&buf, getpagesize(), buf_size); if (err) { fprintf(stderr, "error %s during %s\n", strerror(err), "posix_memalign"); return 1; } - memset(cmp_buf, IO_PATTERN, BUF_SIZE); + cmp_buf = malloc(buf_size); + memset(cmp_buf, IO_PATTERN, buf_size); err = io_setup(4, &ctx); if (err) { @@ -113,8 +153,8 @@ int main(int argc, char *argv[]) eof = 0; /* Keep extending until 8MB (fairly arbitrary) */ - while (eof < 8 * 1024 * 1024) { - memset(buf, IO_PATTERN, BUF_SIZE); + while (eof < size_MB * 1024 * 1024) { + memset(buf, IO_PATTERN, buf_size); fstat(fd, &statbuf); eof = statbuf.st_size; @@ -125,10 +165,10 @@ int main(int argc, char *argv[]) * management and stale block zeroing for races and can lead to * data corruption when not handled properly. */ - io_prep_pwrite(&iocb1, fd, buf, BUF_SIZE/4, eof + 0*BUF_SIZE/4); - io_prep_pwrite(&iocb2, fd, buf, BUF_SIZE/4, eof + 1*BUF_SIZE/4); - io_prep_pwrite(&iocb3, fd, buf, BUF_SIZE/4, eof + 2*BUF_SIZE/4); - io_prep_pwrite(&iocb4, fd, buf, BUF_SIZE/4, eof + 3*BUF_SIZE/4); + io_prep_pwrite(&iocb1, fd, buf, buf_size/4, eof + 0*buf_size/4); + io_prep_pwrite(&iocb2, fd, buf, buf_size/4, eof + 1*buf_size/4); + io_prep_pwrite(&iocb3, fd, buf, buf_size/4, eof + 2*buf_size/4); + io_prep_pwrite(&iocb4, fd, buf, buf_size/4, eof + 3*buf_size/4); err = io_submit(ctx, 4, iocbs); if (err != 4) { @@ -150,20 +190,20 @@ int main(int argc, char *argv[]) * And then read it back. * * Using pread to keep it simple, but AIO has the same effect. - * eof is the prior eof; we just wrote BUF_SIZE more. + * eof is the prior eof; we just wrote buf_size more. */ - if (pread(fd, buf, BUF_SIZE, eof) != BUF_SIZE) { + if (pread(fd, buf, buf_size, eof) != buf_size) { perror("pread"); return 1; } /* * We launched 4 AIOs which, stitched together, should write - * a seamless BUF_SIZE worth of IO_PATTERN to the last block. + * a seamless buf_size worth of IO_PATTERN to the last block. */ - if (memcmp(buf, cmp_buf, BUF_SIZE)) { + if (memcmp(buf, cmp_buf, buf_size)) { printf("corruption while extending from %ld\n", eof); - dump_buffer(buf, 0, BUF_SIZE); + dump_buffer(buf, 0, buf_size); return 1; } } diff --git a/tests/generic/426 b/tests/generic/426 new file mode 100755 index 0000000..8c4e204 --- /dev/null +++ b/tests/generic/426 @@ -0,0 +1,91 @@ +#! /bin/bash +# FS QA Test 426 +# +# Try to trigger a race of free eofblocks and file extending dio writes. +# A known bug of XFS has been fixed by "e4229d6 xfs: fix eofblocks race +# with file extending async dio writes" +# +#----------------------------------------------------------------------- +# 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.* +} + +# get standard environment, filters and checks +. ./common/rc +. ./common/filter + +# remove previous $seqres.full before test +rm -f $seqres.full + +# real QA test starts here + +# Modify as appropriate. +_supported_fs generic +_supported_os Linux +_require_scratch +_require_aiodio aio-dio-eof-race + +# limit the filesystem size, to save the time of filling filesystem +_scratch_mkfs_sized $((256 * 1024 * 1024)) >>$seqres.full 2>&1 +_scratch_mount + +# try to write more bytes than filesystem size to fill the filesystem +$XFS_IO_PROG -f -c "pwrite -S 0x55 0 $((256 * 1024 * 1024 * 2))" \ + $SCRATCH_MNT/fillfs-$seq 2>/dev/null +rm -f $SCRATCH_MNT/fillfs-$seq + +# open & close the file frequently, to trigger xfs_free_eofblocks +while true; do + $XFS_IO_PROG -f -c open $SCRATCH_MNT/tst-aio-dio-eof-race.$seq \ + >/dev/null 2>&1 +done & +open_close_pid=$! + +nr_cpu=`$here/src/feature -o` +fsize=$((nr_cpu * 10)) +if [ $fsize -gt 200 ]; then + fsize=200 +fi +# start a background aio writer, which does several extending loops +# internally and check data integrality +$AIO_TEST -s $fsize -b 65536 $SCRATCH_MNT/tst-aio-dio-eof-race.$seq +status=$? + +kill $open_close_pid +wait $open_close_pid +if [ $status -ne 0 ]; then + od -t x1 $SCRATCH_MNT/tst-aio-dio-eof-race.$seq >> $seqres.full + exit +fi + +# success, all done +status=0 +exit diff --git a/tests/generic/426.out b/tests/generic/426.out new file mode 100644 index 0000000..ad7a01a --- /dev/null +++ b/tests/generic/426.out @@ -0,0 +1,2 @@ +QA output created by 426 +Success, all done. diff --git a/tests/generic/group b/tests/generic/group index 6d6e4f6..70c36f9 100644 --- a/tests/generic/group +++ b/tests/generic/group @@ -428,3 +428,4 @@ 423 auto quick 424 auto quick 425 auto quick attr +426 auto aio rw
It's possible for post-eof blocks to end up being used for direct I/O writes. dio write performs an upfront unwritten extent allocation, sends the dio and then updates the inode size (if necessary) on write completion. If a file release occurs while a file extending dio write is in flight, it is possible to mistake the post-eof blocks for speculative preallocation and incorrectly truncate them from the inode. This means that the resulting dio write completion can discover a hole and allocate new blocks rather than perform unwritten extent conversion. A kernel warning can be reproduced by generic/299 on XFS: XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, \ file: fs/xfs//xfs_trans.c, line: 309 The root cause is that xfs_free_eofblocks() uses i_size to truncate post-eof blocks from the inode, but async, file extending direct writes do not update i_size until write completion, long after inode locks are dropped. Therefore, xfs_free_eofblocks() effectively truncates the inode to the incorrect size. Besides reproduce above kernel warning, the verification of written data is an important distinction between this test and generic/299. For cover this filesystem corruption testing, write this new case to check data integrality manually, not only depend on a kernel warning. To increase the test stress of aio-dio-eof-race, add two arguments to this source code to change the file size will be written. Signed-off-by: Zorro Lang <zlang@redhat.com> --- Hi, V2 did below changes: 1) change aio-dio-eof-race.c, add two arguments to change the file size and buffer size. 2) change fs size from 1G to 256M 3) move open/close loop before $AIO_TEST 4) use new aio-dio-eof-race arguments, and use cpu number to decide the file size. 5) change open/close operation from "cat" to "xfs_io -c open" Thanks, Zorro src/aio-dio-regress/aio-dio-eof-race.c | 74 ++++++++++++++++++++------- tests/generic/426 | 91 ++++++++++++++++++++++++++++++++++ tests/generic/426.out | 2 + tests/generic/group | 1 + 4 files changed, 151 insertions(+), 17 deletions(-) create mode 100755 tests/generic/426 create mode 100644 tests/generic/426.out