From: Luis Henriques <lhenriques@xxxxxxxx> [ Upstream commit 750670341a24cb714e624e0fd7da30900ad93752 ] When filling an inode with info from the MDS, i_blkbits is being initialized using fl_stripe_unit, which contains the stripe unit in bytes. Unfortunately, this doesn't make sense for directories as they have fl_stripe_unit set to '0'. This means that i_blkbits will be set to 0xff, causing an UBSAN undefined behaviour in i_blocksize(): UBSAN: Undefined behaviour in ./include/linux/fs.h:731:12 shift exponent 255 is too large for 32-bit type 'int' Fix this by initializing i_blkbits to CEPH_BLOCK_SHIFT if fl_stripe_unit is zero. Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ceph/inode.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index ca3821b0309f7..b1e49fcf7754f 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -805,7 +805,12 @@ static int fill_inode(struct inode *inode, struct page *locked_page, /* update inode */ inode->i_rdev = le32_to_cpu(info->rdev); - inode->i_blkbits = fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1; + /* directories have fl_stripe_unit set to zero */ + if (le32_to_cpu(info->layout.fl_stripe_unit)) + inode->i_blkbits = + fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1; + else + inode->i_blkbits = CEPH_BLOCK_SHIFT; __ceph_update_quota(ci, iinfo->max_bytes, iinfo->max_files); -- 2.20.1
