On 5/27/22 13:49, Christoph Hellwig wrote:
Add a few helpers to consolidate code for btrfs read repair testing:
- _btrfs_get_first_logical() gets the btrfs logical address for the
first extent in a file
- _btrfs_get_device_path and _btrfs_get_physical use the
btrfs-map-logical tool to find the device path and physical address
for btrfs logical address for a specific mirror
- _btrfs_direct_read_on_mirror and _btrfs_buffered_read_on_mirror
read the data from a specific mirror
These will be used to consolidate the read repair tests and avoid
duplication for new tests.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
---
common/btrfs | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++
common/config | 1 +
2 files changed, 76 insertions(+)
diff --git a/common/btrfs b/common/btrfs
index ac597ca4..b69feeee 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -505,3 +505,78 @@ _btrfs_metadump()
$BTRFS_IMAGE_PROG "$device" "$dumpfile"
[ -n "$DUMP_COMPRESSOR" ] && $DUMP_COMPRESSOR -f "$dumpfile" &> /dev/null
}
+
+# Return the btrfs logical address for the first block in a file
+_btrfs_get_first_logical()
+{
+ local file=$1
+ _require_command "$FILEFRAG_PROG" filefrag
+
+ ${FILEFRAG_PROG} -v $SCRATCH_MNT/foobar >> $seqres.full
+ ${FILEFRAG_PROG} -v $file | _filter_filefrag | cut -d '#' -f 1
+}
+
+# Find the device path for a btrfs logical offset
+_btrfs_get_device_path()
+{
+ local logical=$1
+ local stripe=$2
+
+ _require_command "$BTRFS_MAP_LOGICAL_PROG" btrfs-map-logical
+
+ $BTRFS_MAP_LOGICAL_PROG -l $logical $SCRATCH_DEV | \
+ $AWK_PROG "(\$1 ~ /mirror/ && \$2 ~ /$stripe/) { print \$8 }"
+}
+
+
+# Find the device physical sector for a btrfs logical offset
+_btrfs_get_physical()
+{
+ local logical=$1
+ local stripe=$2
+
+ _require_command "$BTRFS_MAP_LOGICAL_PROG" btrfs-map-logical
+
+ $BTRFS_MAP_LOGICAL_PROG -b -l $logical $SCRATCH_DEV >> $seqres.full 2>&1
+ $BTRFS_MAP_LOGICAL_PROG -l $logical $SCRATCH_DEV | \
+ $AWK_PROG "(\$1 ~ /mirror/ && \$2 ~ /$stripe/) { print \$6 }"
+}
+
+# Read from a specific stripe to test read recovery that corrupted a specific
+# stripe. Btrfs uses the PID to select the mirror, so keep reading until the
+# xfs_io process that performed the read was executed with a PID that ends up
+# on the intended mirror.
+_btrfs_direct_read_on_mirror()
+{
+ local mirror=$1
+ local nr_mirrors=$2
+ local file=$3
+ local offset=$4
+ local size=$5
+
+ while [[ -z $( (( BASHPID % nr_mirrors == mirror )) &&
+ exec $XFS_IO_PROG -d \
+ -c "pread -b $size $offset $size" $file) ]]; do
+ :
+ done
+}
+
+# Read from a specific stripe to test read recovery that corrupted a specific
+# stripe. Btrfs uses the PID to select the mirror, so keep reading until the
+# xfs_io process that performed the read was executed with a PID that ends up
+# on the intended mirror.
+_btrfs_buffered_read_on_mirror()
+{
+ local mirror=$1
+ local nr_mirrors=$2
+ local file=$3
+ local offset=$4
+ local size=$5
+
+ echo 3 > /proc/sys/vm/drop_caches
+ while [[ -z $( (( BASHPID % nr_mirrors == mirror )) &&
+ exec $XFS_IO_PROG \
+ -c "pread -b $size $offset $size" $file) ]]; do
I am confused if it should be BASHPID or PID?
Next, it is ok if the xfs_io_prog fails and returns != 0.
(Part of the test).
But then we will continue in the while loop. No?
Sorry, I am sceptical about this. Could you please clarify
how this works?
Thanks, Anand
+ :
+ done
+}
diff --git a/common/config b/common/config
index c6428f90..df20afc1 100644
--- a/common/config
+++ b/common/config
@@ -228,6 +228,7 @@ export E2IMAGE_PROG="$(type -P e2image)"
export BLKZONE_PROG="$(type -P blkzone)"
export GZIP_PROG="$(type -P gzip)"
export BTRFS_IMAGE_PROG="$(type -P btrfs-image)"
+export BTRFS_MAP_LOGICAL_PROG=$(type -P btrfs-map-logical)
# use 'udevadm settle' or 'udevsettle' to wait for lv to be settled.
# newer systems have udevadm command but older systems like RHEL5 don't.
