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Merge pull request #128 from versity/zab/prealloc_fragmentation

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Zab/prealloc fragmentation
This commit is contained in:
Zach Brown
2023-06-29 09:57:32 -07:00
committed by GitHub
parent 49fe89741d 847916860d
commit a9da27444f
3 changed files with 445 additions and 8 deletions
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37
kmod/src/data.c
View File

@@ -456,11 +456,13 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
} else {
/*
* Preallocation of aligned regions only preallocates if
* the aligned region contains no extents at all. This
* could be fooled by offline sparse extents but we
* don't want to iterate over all offline extents in the
* aligned region.
* Preallocation within aligned regions tries to
* allocate an extent to fill the hole in the region
* that contains iblock. We search for a next extent
* from the start of the region. If it's at the start
* we might have to search again to find an existing
* extent at the end of the region. (This next could be
* given to us by the caller).
*/
div64_u64_rem(iblock, opts.data_prealloc_blocks, &rem);
start = iblock - rem;
@@ -468,8 +470,20 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
ret = scoutfs_ext_next(sb, &data_ext_ops, &args, start, 1, &found);
if (ret < 0 && ret != -ENOENT)
goto out;
if (found.len && found.start < start + count)
count = 1;
/* trim count if there's an extent in the region before iblock */
if (found.len && found.start < iblock) {
count -= (found.start + found.len) - start;
start = found.start + found.len;
/* see if there's also an extent after iblock */
ret = scoutfs_ext_next(sb, &data_ext_ops, &args, iblock, 1, &found);
if (ret < 0 && ret != -ENOENT)
goto out;
}
/* trim count by a next extent in the region */
if (found.len && found.start > start && found.start < start + count)
count = (found.start - start);
}
/* overall prealloc limit */
@@ -1253,6 +1267,7 @@ int scoutfs_data_move_blocks(struct inode *from, u64 from_off,
from_iblock = from_off >> SCOUTFS_BLOCK_SM_SHIFT;
count = (byte_len + SCOUTFS_BLOCK_SM_MASK) >> SCOUTFS_BLOCK_SM_SHIFT;
to_iblock = to_off >> SCOUTFS_BLOCK_SM_SHIFT;
from_start = from_iblock;
/* only move extent blocks inside i_size, careful not to wrap */
from_size = i_size_read(from);
@@ -1329,7 +1344,7 @@ int scoutfs_data_move_blocks(struct inode *from, u64 from_off,
/* find the next extent to move */
ret = scoutfs_ext_next(sb, &data_ext_ops, &from_args,
from_iblock, 1, &ext);
from_start, 1, &ext);
if (ret < 0) {
if (ret == -ENOENT) {
done = true;
@@ -1417,6 +1432,12 @@ int scoutfs_data_move_blocks(struct inode *from, u64 from_off,
i_size_read(from);
i_size_write(to, to_size);
}
/* find next after moved extent, avoiding wrapping */
if (from_start + len < from_start)
from_start = from_iblock + count + 1;
else
from_start += len;
}

322
tests/golden/data-prealloc
View File

@@ -24,3 +24,325 @@
/mnt/test/test/data-prealloc/file-2: 5 extents found
/mnt/test/test/data-prealloc/file-1: 3 extents found
/mnt/test/test/data-prealloc/file-2: 3 extents found
== block writes into region allocs hole
wrote blk 24
wrote blk 32
wrote blk 40
wrote blk 55
wrote blk 63
wrote blk 71
wrote blk 72
wrote blk 79
wrote blk 80
wrote blk 87
wrote blk 88
wrote blk 95
before:
24.. 1:
32.. 1:
40.. 1:
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 0 at pos 0
wrote blk 0
0.. 1:
1.. 7: unwritten
24.. 1:
32.. 1:
40.. 1:
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 0 at pos 1
wrote blk 15
0.. 1:
1.. 14: unwritten
15.. 1:
24.. 1:
32.. 1:
40.. 1:
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 0 at pos 2
wrote blk 19
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
32.. 1:
40.. 1:
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 1 at pos 0
wrote blk 25
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
40.. 1:
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 1 at pos 1
wrote blk 39
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 1 at pos 2
wrote blk 44
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 2 at pos 0
wrote blk 48
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
48.. 1:
49.. 6: unwritten
55.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 2 at pos 1
wrote blk 62
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
48.. 1:
49.. 6: unwritten
55.. 1:
56.. 6: unwritten
62.. 1:
63.. 1:
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 2 at pos 2
wrote blk 67
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
48.. 1:
49.. 6: unwritten
55.. 1:
56.. 6: unwritten
62.. 1:
63.. 1:
64.. 3: unwritten
67.. 1:
68.. 3: unwritten
71.. 2:
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 3 at pos 0
wrote blk 73
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
48.. 1:
49.. 6: unwritten
55.. 1:
56.. 6: unwritten
62.. 1:
63.. 1:
64.. 3: unwritten
67.. 1:
68.. 3: unwritten
71.. 2:
73.. 1:
74.. 5: unwritten
79.. 2:
87.. 2:
95.. 1: eof
writing into existing 3 at pos 1
wrote blk 86
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
48.. 1:
49.. 6: unwritten
55.. 1:
56.. 6: unwritten
62.. 1:
63.. 1:
64.. 3: unwritten
67.. 1:
68.. 3: unwritten
71.. 2:
73.. 1:
74.. 5: unwritten
79.. 2:
81.. 5: unwritten
86.. 1:
87.. 2:
95.. 1: eof
writing into existing 3 at pos 2
wrote blk 92
0.. 1:
1.. 14: unwritten
15.. 1:
16.. 3: unwritten
19.. 1:
20.. 4: unwritten
24.. 1:
25.. 1:
26.. 6: unwritten
32.. 1:
33.. 6: unwritten
39.. 1:
40.. 1:
41.. 3: unwritten
44.. 1:
45.. 3: unwritten
48.. 1:
49.. 6: unwritten
55.. 1:
56.. 6: unwritten
62.. 1:
63.. 1:
64.. 3: unwritten
67.. 1:
68.. 3: unwritten
71.. 2:
73.. 1:
74.. 5: unwritten
79.. 2:
81.. 5: unwritten
86.. 1:
87.. 2:
89.. 3: unwritten
92.. 1:
93.. 2: unwritten
95.. 1: eof

94
tests/tests/data-prealloc.sh
View File

@@ -6,6 +6,15 @@
#
t_require_commands scoutfs stat filefrag dd touch truncate
write_block()
{
local file="$1"
local blk="$2"
dd if=/dev/zero of="$file" bs=4096 seek=$blk count=1 conv=notrunc status=none
echo "wrote blk $blk"
}
write_forwards()
{
local prefix="$1"
@@ -70,6 +79,25 @@ print_extents_found()
filefrag "$prefix"* 2>&1 | grep "extent.*found" | t_filter_fs
}
#
# print the logical start, len, and flags if they're there.
#
print_logical_extents()
{
local file="$1"
filefrag -v -b4096 "$file" 2>&1 | t_filter_fs | awk '
($1 ~ /[0-9]+:/) {
if ($NF !~ /[0-9]+:/) {
flags=$NF
} else {
flags=""
}
print $2, $6, flags
}
'
}
t_save_all_sysfs_mount_options data_prealloc_blocks
t_save_all_sysfs_mount_options data_prealloc_contig_only
restore_options()
@@ -133,4 +161,70 @@ t_set_sysfs_mount_option 0 data_prealloc_contig_only 0
write_forwards $prefix 3
print_extents_found $prefix
#
# prepare aligned regions of 8 blocks that we'll write into.
# We'll right into the first, last, and middle block of each
# region which was prepared with no existing extents, one at
# the start, and one at the end.
#
# Let's keep this last because it creates a ton of output to read
# through.
#
echo "== block writes into region allocs hole"
t_set_sysfs_mount_option 0 data_prealloc_blocks 8
t_set_sysfs_mount_option 0 data_prealloc_contig_only 1
touch "$prefix"
truncate -s 0 "$prefix"
# write initial blocks in regions
base=0
for sides in 0 1 2 3; do
for i in 0 1 2; do
case "$sides" in
# none
0) ;;
# left
1) write_block $prefix $((base + 0)) ;;
# right
2) write_block $prefix $((base + 7)) ;;
# both
3) write_block $prefix $((base + 0))
write_block $prefix $((base + 7)) ;;
esac
((base+=8))
done
done
echo before:
print_logical_extents "$prefix"
# now write into the first, middle, and last empty block of each
t_set_sysfs_mount_option 0 data_prealloc_contig_only 0
base=0
for sides in 0 1 2 3; do
for i in 0 1 2; do
echo "writing into existing $sides at pos $i"
case "$sides" in
# none
0) left=$base; right=$((base + 7));;
# left
1) left=$((base + 1)); right=$((base + 7));;
# right
2) left=$((base)); right=$((base + 6));;
# both
3) left=$((base + 1)); right=$((base + 6));;
esac
case "$i" in
# start
0) write_block $prefix $left ;;
# end
1) write_block $prefix $right ;;
# mid (both has 6 blocks internally)
2) write_block $prefix $((left + 3)) ;;
esac
print_logical_extents "$prefix"
((base+=8))
done
done
t_pass