path: root/mkfs.c
diff options
authorChandan Rajendra <>2016-06-17 11:07:54 +0530
committerDavid Sterba <>2016-06-17 17:11:26 +0200
commit49ec1413a78624d4bf4c99d184c8fbaf99cd0ad4 (patch)
tree07302f30c7e394dbe5bcfa39b9e936278bf1f509 /mkfs.c
parentdf05c7ed455f519e6e15e46196392e4757257305 (diff)
Btrfs-progs: Initialize stripesize to the value of sectorsize
stripesize should ideally be set to the value of sectorsize. However previous versions of btrfs-progs/mkfs.btrfs had set stripesize to a value of 4096. On machines with PAGE_SIZE other than 4096, This could lead to the following scenario, - /dev/loop0, /dev/loop1 and /dev/loop2 are mounted as a single filesystem. The filesystem was created by an older version of mkfs.btrfs which set stripesize to 4k. - losetup -a /dev/loop0: [0030]:19477 (/root/disk-imgs/file-0.img) /dev/loop1: [0030]:16577 (/root/disk-imgs/file-1.img) /dev/loop2: [64770]:3423229 (/root/disk-imgs/file-2.img) - /etc/mtab lists only /dev/loop0 - losetup /dev/loop4 /root/disk-imgs/file-1.img The new mkfs.btrfs invoked as 'mkfs.btrfs -f /dev/loop4' succeeds even though /dev/loop1 has already been mounted and has /root/disk-imgs/file-1.img as its backing file. The above behaviour occurs because check_super() function returns an error code (due to stripesize not being set to 4096) and hence check_mounted_where() function treats /dev/loop1 as a disk containing a filesystem other than Btrfs. Hence as a workaround this commit allows 4096 as a valid stripesize. Signed-off-by: Chandan Rajendra <> Signed-off-by: David Sterba <>
Diffstat (limited to 'mkfs.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/mkfs.c b/mkfs.c
index a3a3c140..697bdc2e 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -1482,6 +1482,7 @@ int main(int argc, char **argv)
sectorsize = max(sectorsize, (u32)sysconf(_SC_PAGESIZE));
+ stripesize = sectorsize;
saved_optind = optind;
dev_cnt = argc - optind;
if (dev_cnt == 0)