On Wed, 2020-11-11 at 15:39 +0000, Luis Henriques wrote:
> When doing a rename across quota realms, there's a corner case that isn't
> handled correctly. Here's a testcase:
>
> mkdir files limit
> truncate files/file -s 10G
> setfattr limit -n ceph.quota.max_bytes -v 1000000
> mv files limit/
>
> The above will succeed because ftruncate(2) won't result in an immediate
> notification of the MDSs with the new file size, and thus the quota realms
> stats won't be updated.
>
> This patch forces a sync with the MDS every time there's an ATTR_SIZE that
> sets a new i_size, even if we have Fx caps.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: dffdcd71458e ("ceph: allow rename operation under different quota realms")
> URL: https://tracker.ceph.com/issues/36593
> Signed-off-by: Luis Henriques <lhenriques@xxxxxxx>
> ---
> fs/ceph/inode.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 526faf4778ce..30e3f240ac96 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -2136,15 +2136,8 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
> if (ia_valid & ATTR_SIZE) {
> dout("setattr %p size %lld -> %lld\n", inode,
> inode->i_size, attr->ia_size);
> - if ((issued & CEPH_CAP_FILE_EXCL) &&
> - attr->ia_size > inode->i_size) {
> - i_size_write(inode, attr->ia_size);
> - inode->i_blocks = calc_inode_blocks(attr->ia_size);
> - ci->i_reported_size = attr->ia_size;
> - dirtied |= CEPH_CAP_FILE_EXCL;
> - ia_valid |= ATTR_MTIME;
> - } else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
> - attr->ia_size != inode->i_size) {
> + if ((issued & (CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_SHARED)) ||
> + (attr->ia_size != inode->i_size)) {
> req->r_args.setattr.size = cpu_to_le64(attr->ia_size);
> req->r_args.setattr.old_size =
> cpu_to_le64(inode->i_size);
Hmm...this makes truncates more expensive when we have caps. I'd rather
not do that if we can help it.
What about instead having the client mimic a fsync when there is a
rename across quota realms? If we can't tell that reliably then we could
also just do an effective fsync ahead of any cross-directory rename?
--
Jeff Layton <jlayton@xxxxxxxxxx>
