[rh7] ploop: Add comment about ploop_pvd_header::m_FirstBlockOffset

Submitted by Kirill Tkhai on Aug. 20, 2019, 9:55 a.m.

Details

Message ID 156629494517.20867.16862974678316022797.stgit@localhost.localdomain
State New
Series "ploop: Add comment about ploop_pvd_header::m_FirstBlockOffset"
Headers show

Commit Message

Kirill Tkhai Aug. 20, 2019, 9:55 a.m.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
 drivers/block/ploop/fmt_ploop1.c |    5 +++++
 1 file changed, 5 insertions(+)

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diff --git a/drivers/block/ploop/fmt_ploop1.c b/drivers/block/ploop/fmt_ploop1.c
index 5ca9f257be31..f54b4bf2039c 100644
--- a/drivers/block/ploop/fmt_ploop1.c
+++ b/drivers/block/ploop/fmt_ploop1.c
@@ -659,6 +659,11 @@  static int expand_holes_bitmap(struct ploop_delta *delta,
 	if (!delta->holes_bitmap)
 		return 0;
 
+	/*
+	 * According to BUG_ON() in ploop1_prepare_grow(),
+	 * we do not support zero m_FirstBlockOffset
+	 * at least since 2013.
+	 */
 	md_off = vh->m_FirstBlockOffset >> log;
 	nr = md_off + vh->m_Size;