[PATCH,2/2] ext4: change type to same as sectors in disk_stats

From: Huijin Park
Date: Fri Nov 30 2018 - 04:33:28 EST


From: "huijin.park" <huijin.park@xxxxxxxxxxx>

This patch changes the 's_sectors_written_start' type to u64
same as the 'sectors' type in disk_stats.
Because if the 'sectors' has more than about 2TiB,
the 's_sectors_written_start' will overflow in 32 bit system.
And it makes invalid statistics([session|lifetime]_write_kbytes).

Signed-off-by: huijin.park <huijin.park@xxxxxxxxxxx>
---
fs/ext4/ext4.h | 2 +-
fs/ext4/sysfs.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 3f89d0a..d3a08b2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1457,7 +1457,7 @@ struct ext4_sb_info {
struct ext4_locality_group __percpu *s_locality_groups;

/* for write statistics */
- unsigned long s_sectors_written_start;
+ u64 s_sectors_written_start;
u64 s_kbytes_written;

/* the size of zero-out chunk */
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 9212a02..59ac5cf 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -57,7 +57,7 @@ static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)

if (!sb->s_bdev->bd_part)
return snprintf(buf, PAGE_SIZE, "0\n");
- return snprintf(buf, PAGE_SIZE, "%lu\n",
+ return snprintf(buf, PAGE_SIZE, "%llu\n",
(part_stat_read(sb->s_bdev->bd_part,
sectors[STAT_WRITE]) -
sbi->s_sectors_written_start) >> 1);
--
1.7.9.5