On 11/10/21 11:50 PM, Miklos Szeredi wrote: > On Tue, 2 Nov 2021 at 06:26, Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx> wrote: >> >> When the per inode DAX hint changes while the file is still *opened*, it >> is quite complicated and maybe fragile to dynamically change the DAX >> state. >> >> Hence mark the inode and corresponding dentries as DONE_CACHE once the >> per inode DAX hint changes, so that the inode instance will be evicted >> and freed as soon as possible once the file is closed and the last >> reference to the inode is put. And then when the file gets reopened next >> time, the new instantiated inode will reflect the new DAX state. >> >> In summary, when the per inode DAX hint changes for an *opened* file, the >> DAX state of the file won't be updated until this file is closed and >> reopened later. > > This patch does nothing, since fuse already uses .drop_inode = > generic_delete_inode, which is has the same effect as setting > I_DONTCACHE, at least in the fuse case (inode should never be dirty at > eviction). Yes, it is. .drop_inode() of FUSE will always free inode. Here we only need to set dentry as DCACHE_DONTCACHE. Here I just call d_mark_dontcache() directly, though I_DONTCACHE is useless but harmless in the case of FUSE... > In fact it may be cleaner to set I_DONTCACHE > unconditionally and remove the .drop_inode callback setting. It works in both cases, I mean, in current case (current code retained untouched) and the case you described above. -- Thanks, Jeffle
