Ramping up data preallocation

Ramps up data preallocation based on the number of online
blocks. This results in a simple 2<<n block allocation pattern
until n=11 (2048) - the default value of data_prealloc_blocks.

Signed-off-by: Auke Kok <auke.kok@versity.com>

kmod/src/data.c

@@ -384,6 +384,12 @@ static inline u64 ext_last(struct scoutfs_extent *ext)
  * This can waste a lot of space for small or sparse files but is
  * reasonable when a file population is known to be large and dense but
  * known to be written with non-streaming write patterns.
+ *
+ * In either strategy, preallocation ramps up proportionally with the
+ * file's online block count rather than jumping to the full prealloc
+ * size.  This avoids overallocation for small files in mixed-size
+ * workloads while still allowing large files to benefit from full
+ * preallocation.
  */
 static int alloc_block(struct super_block *sb, struct inode *inode,
 		       struct scoutfs_extent *ext, u64 iblock,
@@ -400,6 +406,7 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
 	struct scoutfs_extent found;
 	struct scoutfs_extent pre = {0,};
 	bool undo_pre = false;
+	bool have_onoff = false;
 	u64 blkno = 0;
 	u64 online;
 	u64 offline;
@@ -445,6 +452,7 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
 		 * blocks.
 		 */
 		scoutfs_inode_get_onoff(inode, &online, &offline);
+		have_onoff = true;
 		if (iblock > 1 && iblock == online) {
 			ret = scoutfs_ext_next(sb, &data_ext_ops, &args,
 					       iblock, 1, &found);
@@ -491,6 +499,16 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
 	/* overall prealloc limit */
 	count = min_t(u64, count, opts.data_prealloc_blocks);
 
+	/*
+	 * Ramp preallocation up proportionally with the file's online
+	 * block count rather than jumping to the full prealloc size.
+	 */
+	if (!ext->len) {
+		if (!have_onoff)
+			scoutfs_inode_get_onoff(inode, &online, &offline);
+		count = max_t(u64, 1, min(count, online));
+	}
+
 	ret = scoutfs_alloc_data(sb, datinf->alloc, datinf->wri,
 				 &datinf->dalloc, count, &blkno, &count);
 	if (ret < 0)

kmod/src/quota.c

@@ -34,6 +34,7 @@
 #include "totl.h"
 #include "util.h"
 #include "quota.h"
+#include "trans.h"
 #include "counters.h"
 #include "scoutfs_trace.h"
 
@@ -1086,6 +1087,10 @@ int scoutfs_quota_mod_rule(struct super_block *sb, bool is_add,
 	if (ret < 0)
 		goto out;
 
+	ret = scoutfs_hold_trans(sb, true);
+	if (ret < 0)
+		goto out;
+
 	down_write(&qtinf->rwsem);
 
 	if (is_add) {
@@ -1095,28 +1100,30 @@ int scoutfs_quota_mod_rule(struct super_block *sb, bool is_add,
 		else if (ret == 0)
 			ret = -EEXIST;
 		if (ret < 0)
-			goto unlock;
+			goto release;
 
 		rule_to_rule_val(&rv, &rule);
 		ret = scoutfs_item_create(sb, &key, &rv, sizeof(rv), lock);
 		if (ret < 0)
-			goto unlock;
+			goto release;
 
 	} else {
 		ret = find_rule(sb, &rule, &key, lock) ?:
 		      scoutfs_item_delete(sb, &key, lock);
 		if (ret < 0)
-			goto unlock;
+			goto release;
 	}
 
 	scoutfs_quota_invalidate(sb);
 	ret = 0;
 
-unlock:
+release:
 	up_write(&qtinf->rwsem);
-	scoutfs_unlock(sb, lock, SCOUTFS_LOCK_WRITE);
+	scoutfs_release_trans(sb);
 
 out:
+	scoutfs_unlock(sb, lock, SCOUTFS_LOCK_WRITE);
+
 	if (is_add)
 		trace_scoutfs_quota_add_rule(sb, &rule, ret);
 	else

tests/funcs/filter.sh

@@ -87,7 +87,7 @@ awk '
 	( in_block == 2 ) {
 		buf = buf $0 "\n"
 		if ($0 ~ /<\/TASK>/) {
-			if (buf ~ /xfs_nondir_ilock_class/ && buf ~ /fs_reclaim/) {
+			if (buf ~ /xfs_(nondir_|dir_)?ilock_class/ && buf ~ /fs_reclaim/) {
 				# known xfs lockdep false positive, discard
 			} else {
 				printf "%s", buf

tests/golden/data-prealloc

@@ -8,10 +8,10 @@
 /mnt/test/test/data-prealloc/file-1: extents: 32
 /mnt/test/test/data-prealloc/file-2: extents: 32
 == any writes to region prealloc get full extents
-/mnt/test/test/data-prealloc/file-1: extents: 4
-/mnt/test/test/data-prealloc/file-2: extents: 4
-/mnt/test/test/data-prealloc/file-1: extents: 4
-/mnt/test/test/data-prealloc/file-2: extents: 4
+/mnt/test/test/data-prealloc/file-1: extents: 8
+/mnt/test/test/data-prealloc/file-2: extents: 8
+/mnt/test/test/data-prealloc/file-1: extents: 8
+/mnt/test/test/data-prealloc/file-2: extents: 8
 == streaming offline writes get full extents either way
 /mnt/test/test/data-prealloc/file-1: extents: 4
 /mnt/test/test/data-prealloc/file-2: extents: 4
@@ -20,8 +20,8 @@
 == goofy preallocation amounts work
 /mnt/test/test/data-prealloc/file-1: extents: 6
 /mnt/test/test/data-prealloc/file-2: extents: 6
-/mnt/test/test/data-prealloc/file-1: extents: 6
-/mnt/test/test/data-prealloc/file-2: extents: 6
+/mnt/test/test/data-prealloc/file-1: extents: 10
+/mnt/test/test/data-prealloc/file-2: extents: 10
 /mnt/test/test/data-prealloc/file-1: extents: 3
 /mnt/test/test/data-prealloc/file-2: extents: 3
 == block writes into region allocs hole

tests/run-tests.sh

@@ -694,8 +694,8 @@ for t in $tests; do
 		if [ "$sts" == "$T_PASS_STATUS" ]; then
 			dmesg | t_filter_dmesg > "$T_TMPDIR/dmesg.after"
 			diff --old-line-format="" --unchanged-line-format="" \
-				"$T_TMPDIR/dmesg.before" "$T_TMPDIR/dmesg.after" > \
-				"$T_TMPDIR/dmesg.new"
+				"$T_TMPDIR/dmesg.before" "$T_TMPDIR/dmesg.after" | \
+				grep -v '^$' > "$T_TMPDIR/dmesg.new"
 
 			if [ -s "$T_TMPDIR/dmesg.new" ]; then
 				message="unexpected messages in dmesg"