Re: [PATCH 4/8] Fix btrfs/095 to work on non-4k block sized filesystems

Filipe Manana
2015-12-10T17:27:21Z

On Mon, Nov 30, 2015 at 10:17 AM, Chandan Rajendra
<chandan@linux.vnet.ibm.com> wrote:
> This commit makes use of the new _filter_xfs_io_blocks_modified filtering
> function to print information in terms of file blocks rather than file
> offset.
>
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>

Thanks!

> ---
> tests/btrfs/095 | 110 +++++++++++++++++++++++++++++-----------------------
> tests/btrfs/095.out | 42 ++++++++++++++++----
> 2 files changed, 96 insertions(+), 56 deletions(-)
>
> diff --git a/tests/btrfs/095 b/tests/btrfs/095
> index 1b4ba90..dec530c 100755
> --- a/tests/btrfs/095
> +++ b/tests/btrfs/095
> @@ -63,84 +63,98 @@ _scratch_mkfs >>$seqres.full 2>&1
> _init_flakey
> _mount_flakey
>
> -# Create prealloc extent covering range [160K, 620K[
> -$XFS_IO_PROG -f -c "falloc 160K 460K" $SCRATCH_MNT/foo
> +BLOCK_SIZE=$(get_block_size $SCRATCH_MNT)
>
> -# Now write to the last 80K of the prealloc extent plus 40K to the unallocated
> -# space that immediately follows it. This creates a new extent of 40K that spans
> -# the range [620K, 660K[.
> -$XFS_IO_PROG -c "pwrite -S 0xaa 540K 120K" $SCRATCH_MNT/foo | _filter_xfs_io
> +# Create prealloc extent covering file block range [40, 155[
> +$XFS_IO_PROG -f -c "falloc $((40 * $BLOCK_SIZE)) $((115 * $BLOCK_SIZE))" \
> + $SCRATCH_MNT/foo
> +
> +# Now write to the last 20 blocks of the prealloc extent plus 10 blocks to the
> +# unallocated space that immediately follows it. This creates a new extent of 10
> +# blocks that spans the block range [155, 165[.
> +$XFS_IO_PROG -c "pwrite -S 0xaa $((135 * $BLOCK_SIZE)) $((30 * $BLOCK_SIZE))" \
> + $SCRATCH_MNT/foo | _filter_xfs_io_blocks_modified
>
> # At this point, there are now 2 back references to the prealloc extent in our
> -# extent tree. Both are for our file offset 160K and one relates to a file
> -# extent item with a data offset of 0 and a length of 380K, while the other
> -# relates to a file extent item with a data offset of 380K and a length of 80K.
> +# extent tree. Both are for our file offset mapped by the 40th block of the file
> +# and one relates to a file extent item with a data offset of 0 and a length of
> +# 95 blocks, while the other relates to a file extent item with a data offset of
> +# 95 blocks and a length of 20 blocks.
>
> # Make sure everything done so far is durably persisted (all back references are
> # in the extent tree, etc).
> sync
>
> -# Now clone all extents of our file that cover the offset 160K up to its eof
> -# (660K at this point) into itself at offset 2M. This leaves a hole in the file
> -# covering the range [660K, 2M[. The prealloc extent will now be referenced by
> -# the file twice, once for offset 160K and once for offset 2M. The 40K extent
> -# that follows the prealloc extent will also be referenced twice by our file,
> -# once for offset 620K and once for offset 2M + 460K.
> -$CLONER_PROG -s $((160 * 1024)) -d $((2 * 1024 * 1024)) -l 0 $SCRATCH_MNT/foo \
> - $SCRATCH_MNT/foo
> -
> -# Now create one new extent in our file with a size of 100Kb. It will span the
> -# range [3M, 3M + 100K[. It also will cause creation of a hole spanning the
> -# range [2M + 460K, 3M[. Our new file size is 3M + 100K.
> -$XFS_IO_PROG -c "pwrite -S 0xbb 3M 100K" $SCRATCH_MNT/foo | _filter_xfs_io
> +# Now clone all extents of our file that cover the file range spanned by 40th
> +# block up to its eof (165th block at this point) into itself at 512th
> +# block. This leaves a hole in the file covering the block range [165, 512[. The
> +# prealloc extent will now be referenced by the file twice, once for offset
> +# mapped by the 40th block and once for offset mapped by 512th block. The 10
> +# blocks extent that follows the prealloc extent will also be referenced twice
> +# by our file, once for offset mapped by the 155th block and once for offset
> +# (512 block + 115 blocks)
> +$CLONER_PROG -s $((40 * $BLOCK_SIZE)) -d $((512 * $BLOCK_SIZE)) -l 0 \
> + $SCRATCH_MNT/foo $SCRATCH_MNT/foo
> +
> +# Now create one new extent in our file with a size of 25 blocks. It will span
> +# the block range [768, 768 + 25[. It also will cause creation of a hole
> +# spanning the block range [512 + 115, 768[. Our new file size is the file
> +# offset mapped by (768 + 25)th block.
> +$XFS_IO_PROG -c "pwrite -S 0xbb $((768 * $BLOCK_SIZE)) $((25 * $BLOCK_SIZE))" \
> + $SCRATCH_MNT/foo | _filter_xfs_io_blocks_modified
>
> # At this point, there are now (in memory) 4 back references to the prealloc
> # extent.
> #
> -# Two of them are for file offset 160K, related to file extent items
> -# matching the file offsets 160K and 540K respectively, with data offsets of
> -# 0 and 380K respectively, and with lengths of 380K and 80K respectively.
> +# Two of them are for file offset mapped by the 40th block, related to file
> +# extent items matching the file offsets mapped by 40th and 135th block
> +# respectively, with data offsets of 0 and 95 blocks respectively, and with
> +# lengths of 95 and 20 blocks respectively.
> #
> -# The other two references are for file offset 2M, related to file extent items
> -# matching the file offsets 2M and 2M + 380K respectively, with data offsets of
> -# 0 and 380K respectively, and with lengths of 380K and 80K respectively.
> +# The other two references are for file offset mapped by 512th block, related to
> +# file extent items matching the file offsets mapped by 512th and (512 + 95)th
> +# block respectively, with data offsets mapped by 0th and 95th block
> +# respectively, and with lengths of 95 and 20 blocks respectively.
> #
> -# The 40K extent has 2 back references, one for file offset 620K and the other
> -# for file offset 2M + 460K.
> +# The 10 block extent has 2 back references, one for file offset mapped by 155th
> +# block and the other for file offset mapped by (512 + 115)th block.
> #
> -# The 100K extent has a single back reference and it relates to file offset 3M.
> +# The 25 blocks extent has a single back reference and it relates to file offset
> +# mapped by 768th block.
> +
>
> -# Now clone our 100K extent into offset 600K. That offset covers the last 20K
> -# of the prealloc extent, the whole 40K extent and 40K of the hole starting at
> -# offset 660K.
> -$CLONER_PROG -s $((3 * 1024 * 1024)) -d $((600 * 1024)) -l $((100 * 1024)) \
> +# Now clone our 25 block extent into offset mapped by 150th block. That offset
> +# covers the last 5 blocks of the prealloc extent, the whole 10 block extent and
> +# 10 blocks of the hole starting at offset mapped by 165th block.
> +$CLONER_PROG -s $((768 * $BLOCK_SIZE)) -d $((150 * $BLOCK_SIZE)) -l $((25 * $BLOCK_SIZE)) \
> $SCRATCH_MNT/foo $SCRATCH_MNT/foo
>
> -# At this point there's only one reference to the 40K extent, at file offset
> -# 2M + 460K, we have 4 references for the prealloc extent (2 for file offset
> -# 160K and 2 for file offset 2M) and 2 references for the 100K extent (1 for
> -# file offset 3M and a new one for file offset 600K).
> +# At this point there's only one reference to the 10 block extent, at file
> +# offset mapped by (512 + 115) block, we have 4 references for the prealloc
> +# extent (2 for file offset mapped by 40th block and 2 for file offset mapped by
> +# 512th block) and 2 references for the 25 block extent (1 for file offset
> +# mapped by 768th block and a new one for file offset mapped by 150th block).
>
> # Now fsync our file to make all its new data and metadata updates are durably
> # persisted and present if a power failure/crash happens after a successful
> # fsync and before the next transaction commit.
> $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo
>
> -echo "File digest before power failure:"
> -md5sum $SCRATCH_MNT/foo | _filter_scratch
> +echo "File contents before power failure:"
> +od -t x1 $SCRATCH_MNT/foo | _filter_od
>
> # During log replay, the btrfs delayed references implementation used to run the
> # deletion of back references before the addition of new back references, which
> # made the addition fail as it didn't find the key in the extent tree that it
> -# was looking for. The failure triggered by this test was related to the 40K
> -# extent, which got 1 reference dropped and 1 reference added during the fsync
> -# log replay - when running the delayed references at transaction commit time,
> -# btrfs was applying the deletion before the insertion, resulting in a failure
> -# of the insertion that ended up turning the fs into read-only mode.
> +# was looking for. The failure triggered by this test was related to the 10
> +# block extent, which got 1 reference dropped and 1 reference added during the
> +# fsync log replay - when running the delayed references at transaction commit
> +# time, btrfs was applying the deletion before the insertion, resulting in a
> +# failure of the insertion that ended up turning the fs into read-only mode.
> _flakey_drop_and_remount
>
> -echo "File digest after log replay:"
> -md5sum $SCRATCH_MNT/foo | _filter_scratch
> +echo "File contents after log replay:"
> +od -t x1 $SCRATCH_MNT/foo | _filter_od
>
> _unmount_flakey
>
> diff --git a/tests/btrfs/095.out b/tests/btrfs/095.out
> index e93435c..e73b24d 100644
> --- a/tests/btrfs/095.out
> +++ b/tests/btrfs/095.out
> @@ -1,9 +1,35 @@
> QA output created by 095
> -wrote 122880/122880 bytes at offset 552960
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -wrote 102400/102400 bytes at offset 3145728
> -XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> -File digest before power failure:
> -beaf47c36659ac29bb9363fb8ffa10a1 SCRATCH_MNT/foo
> -File digest after log replay:
> -beaf47c36659ac29bb9363fb8ffa10a1 SCRATCH_MNT/foo
> +Blocks modified: [135 - 164]
> +Blocks modified: [768 - 792]
> +File contents before power failure:
> +0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +207 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +226 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
> +*
> +257 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +1137 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +1175 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +1400 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
> +*
> +1431
> +File contents after log replay:
> +0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +207 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +226 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
> +*
> +257 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +1137 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
> +*
> +1175 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +1400 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
> +*
> +1431
> --
> 2.1.0
>

--
Filipe David Manana,

"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."