p9fs: fix panics in p9fs_vget_common

[njain15_protonmail.com]

Summary

This is similar to D55755, with some additional fixes / refactoring.

vfs_hash_insert() already calls vgone() and vput() on the node, so it will call p9fs_reclaim(). Same with ismntque. As for p9fs_reload_stats_dotl() case, we need to call vgone() before vput(), since the current state of the vnode will be uninitialized when we get there.

[njain15_protonmail.com]

Could you commit it as well?

[kib]

In D58632#1345651, @njain15_protonmail.com wrote:

Could you commit it as well?

Mail me git-formatted patch, with the right metadata.