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overlay/061: enhance mmap ro/rw inconsistencies test

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overlay/061 is currently the only overlay test that is expected to
fail on upstream kernel.

It is a flavor of test overlay/016 with mread in stead of pread.
The ro/rw inconsistencies related to file read()/write() API were
fixed with stacked file operations in v4.19, but the ro/rw
inconsistencies related to shared mmap read/write remain to be
fixed.

The test currently checks cache coherency between mmap read and file
write(), but this sort of cache coherency is a Linux implementation
detail not a requirement of the API.

Instead of mread vs. pwrite, check consistency of mread vs. mwrite
to shared mmap, which is required by the MMAP_SHARED API.

Because we can, perform the test on shared memory that maps files
that are already close and check also that mwrite after file is
closed is persistent. This adds test coverage for future overlayfs
writeback code.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
This commit is contained in:
Amir Goldstein
2019-01-27 10:38:50 +02:00
committed by Eryu Guan
parent ebc6c083d3
commit 43c3528091
2 changed files with 31 additions and 9 deletions
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tests/overlay/061
+29 -7
View File
@@ -4,14 +4,15 @@
#
# FSQA Test No. 061
#
# Test ro/rw fd data inconsistecies
# Test memory mapped data inconsistencies
#
# This is a variant of test overlay/016 with mread instead of pread.
#
# This simple test demonstrates a known issue with overlayfs:
# - process A opens file F for read + mmap
# - process B writes new data to file F
# - process A reads old data from mapped memory
# - process A created shared ro mmap on file F
# - process B created shared rw mmap on file F
# - process B writes new data to shared mmap
# - process A reads old data from shared mmap
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
@@ -49,15 +50,36 @@ echo "This is old news" > $lowerdir/foo
_scratch_mount
filter_xfs_io_mmap()
{
# filter out these lines:
# [000] 0x7f3d9aece000 - 0x7f3d9aece010 r-- SCRATCH_MNT/foo (0 : 16)
grep -Fv '[00'
}
#
# mmap MAP_SHARED|PROT_READ of rofd
# write to rwfd
# read from mapped memory
# mmap MAP_SHARED|PROT_WRITE of rwfd
# write to rw mmap
# read from ro mmap
#
$XFS_IO_PROG -r $SCRATCH_MNT/foo \
-C "mmap -r 0 16" \
-C "close" \
-C "open $SCRATCH_MNT/foo" \
-C "pwrite -S 0x61 0 16" \
-C "mmap -w 0 16" \
-C "close" \
-C "mwrite -S 0x61 0 16" \
-C "munmap" \
-C "mread -v 0 16" \
| _filter_xfs_io | _filter_scratch | filter_xfs_io_mmap
_scratch_cycle_mount
# Verify mmap write after close has persisted through mount cycle
echo "After mount cycle:"
$XFS_IO_PROG -r $SCRATCH_MNT/foo \
-C "mmap -r 0 16" \
-C "mread -v 0 16" \
| _filter_xfs_io | _filter_scratch
tests/overlay/061.out
+2 -2
View File
@@ -1,4 +1,4 @@
QA output created by 061
wrote 16/16 bytes at offset 0
XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
00000000: 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 aaaaaaaaaaaaaaaa
After mount cycle:
00000000: 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 61 aaaaaaaaaaaaaaaa