[PATCH v3 1/2] common/dmlogwrites: add _require_log_writes_sized helper

Add a new helper function _require_log_writes_sized() to check if the
LOGWRITES_DEV meets a minimum size requirement.

This is useful for tests that use dm-log-writes with additional space
requirements, such as creating LVM snapshots during log replay or tests
that generate large amounts of logged I/O operations.

The function takes a size parameter in KB, calls _require_log_writes()
internally, and skips the test if LOGWRITES_DEV is smaller than the
required size.

Suggested-by: Darrick J. Wong <[email protected]>
Suggested-by: Anand Jain <[email protected]>
Signed-off-by: Disha Goel <[email protected]>
---
v2 -> v3:
- Fixed variable declaration order - declare all local variables at the
  beginning of the function
- Use $size instead of $1 for clarity in the comparison

 common/dmlogwrites | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/common/dmlogwrites b/common/dmlogwrites
index a27e1966..b457ef7f 100644
--- a/common/dmlogwrites
+++ b/common/dmlogwrites
@@ -14,6 +14,22 @@ _require_log_writes()
 	_require_test_program "log-writes/replay-log"
 }
 
+# Require a log writes device of a minimum size
+# $1: minimum size in KB
+_require_log_writes_sized()
+{
+	local size=$1
+	local devsize
+
+	[ $# -eq 1 ] || _fail "_require_log_writes_sized: expected size param"
+
+	_require_log_writes
+
+	devsize=$(_get_device_size $LOGWRITES_DEV)
+	[ $devsize -lt $size ] && \
+		_notrun "LOGWRITES_DEV too small, ${devsize}KB < ${size}KB"
+}
+
 # Starting from v4.15-rc1, DAX support was added to dm-log-writes, but note
 # that it doesn't track the data that we write via the mmap(), so we can't do
 # any data integrity checking. We can only verify that the metadata writes for
-- 
2.45.1