On Sun, 21 Jul 2013, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
>
> The MDS uses caps message to notify clients about deleted inode.
> when receiving a such message, invalidate any alias of the inode.
> This makes the kernel release the inode ASAP.
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> ---
> fs/ceph/caps.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 25442b4..b446fdd 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -2334,6 +2334,28 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
> }
>
> /*
> + * Invalidate unlinked inode's aliases, so we can drop the inode
> + * from the cache ASAP.
> + */
> +static void invalidate_aliases(struct inode *inode)
> +{
> + struct dentry *dn;
> +
> + dout("invalidate_aliases inode %p\n", inode);
> + d_prune_aliases(inode);
> + while ((dn = d_find_alias(inode))) {
> + d_delete(dn);
> + dput(dn);
I don't think this loop is safe. d_delete() won't unlink the inode if
there are other refs to the dentry, which would make this get stuck in a
loop. Maybe simple checking if we get the same dentry back from
d_find_alias() as the previous call?
> + /*
> + * for dir inode, d_find_alias() can return
> + * disconnected dentry
> + */
> + if (S_ISDIR(inode->i_mode))
> + break;
> + }
If we handle the more general case, I'm not sure we need any special case
here for the directory... although I confess I'm not sure why disconnected
dentries should be treated specially at all.
> +}
> +
> +/*
> * Handle a cap GRANT message from the MDS. (Note that a GRANT may
> * actually be a revocation if it specifies a smaller cap set.)
> *
> @@ -2363,6 +2385,7 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
> int writeback = 0;
> int revoked_rdcache = 0;
> int queue_invalidate = 0;
> + int deleted_inode = 0;
>
> dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
> inode, cap, mds, seq, ceph_cap_string(newcaps));
> @@ -2407,8 +2430,12 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
> from_kgid(&init_user_ns, inode->i_gid));
> }
>
> - if ((issued & CEPH_CAP_LINK_EXCL) == 0)
> + if ((issued & CEPH_CAP_LINK_EXCL) == 0) {
> set_nlink(inode, le32_to_cpu(grant->nlink));
> + if (inode->i_nlink == 0 &&
> + (newcaps & (CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL)))
> + deleted_inode = 1;
> + }
>
> if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
> int len = le32_to_cpu(grant->xattr_len);
> @@ -2517,6 +2544,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
> ceph_queue_writeback(inode);
> if (queue_invalidate)
> ceph_queue_invalidate(inode);
> + if (deleted_inode)
> + invalidate_aliases(inode);
> if (wake)
> wake_up_all(&ci->i_cap_wq);
This looks good, though.
Thanks!
sage
>
> --
> 1.8.1.4
>
>
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