From: "NeilBrown" <neilb@suse.de>
To: "Jeff Layton" <jlayton@kernel.org>
Cc: tytso@mit.edu, adilger.kernel@dilger.ca, djwong@kernel.org,
david@fromorbit.com, trondmy@hammerspace.com,
viro@zeniv.linux.org.uk, zohar@linux.ibm.com, xiubli@redhat.com,
chuck.lever@oracle.com, lczerner@redhat.com, jack@suse.cz,
bfields@fieldses.org, brauner@kernel.org, fweimer@redhat.com,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, ceph-devel@vger.kernel.org,
linux-ext4@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-xfs@vger.kernel.org, "Jeff Layton" <jlayton@redhat.com>
Subject: Re: [PATCH v6 3/9] vfs: plumb i_version handling into struct kstat
Date: Tue, 04 Oct 2022 10:14:32 +1100 [thread overview]
Message-ID: <166483887224.14457.15787196896853726744@noble.neil.brown.name> (raw)
In-Reply-To: <20220930111840.10695-4-jlayton@kernel.org>
On Fri, 30 Sep 2022, Jeff Layton wrote:
> From: Jeff Layton <jlayton@redhat.com>
>
> The NFS server has a lot of special handling for different types of
> change attribute access, depending on what sort of inode we have. In
> most cases, it's doing a getattr anyway and then fetching that value
> after the fact.
>
> Rather that do that, add a new STATX_VERSION flag that is a kernel-only
> symbol (for now). If requested and getattr can implement it, it can fill
> out this field. For IS_I_VERSION inodes, add a generic implementation in
> vfs_getattr_nosec. Take care to mask STATX_VERSION off in requests from
> userland and in the result mask.
>
> Eventually if we decide to make this available to userland, we can just
> designate a field for it in struct statx, and move the STATX_VERSION
> definition to the uapi header.
Above does not mention STATX_ATTR_VERSION_MONOTONIC, but it appears in
that patch - which is confusing.
But the patch is good, so
Reviewed-by: NeilBrown <neilb@suse.de>
Thanks,
NeilBrown
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/stat.c | 17 +++++++++++++++--
> include/linux/stat.h | 9 +++++++++
> 2 files changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/fs/stat.c b/fs/stat.c
> index a7930d744483..e7f8cd4b24e1 100644
> --- a/fs/stat.c
> +++ b/fs/stat.c
> @@ -17,6 +17,7 @@
> #include <linux/syscalls.h>
> #include <linux/pagemap.h>
> #include <linux/compat.h>
> +#include <linux/iversion.h>
>
> #include <linux/uaccess.h>
> #include <asm/unistd.h>
> @@ -118,6 +119,11 @@ int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
> stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
> STATX_ATTR_DAX);
>
> + if ((request_mask & STATX_VERSION) && IS_I_VERSION(inode)) {
> + stat->result_mask |= STATX_VERSION;
> + stat->version = inode_query_iversion(inode);
> + }
> +
> mnt_userns = mnt_user_ns(path->mnt);
> if (inode->i_op->getattr)
> return inode->i_op->getattr(mnt_userns, path, stat,
> @@ -587,9 +593,11 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
>
> memset(&tmp, 0, sizeof(tmp));
>
> - tmp.stx_mask = stat->result_mask;
> + /* STATX_VERSION is kernel-only for now */
> + tmp.stx_mask = stat->result_mask & ~STATX_VERSION;
> tmp.stx_blksize = stat->blksize;
> - tmp.stx_attributes = stat->attributes;
> + /* STATX_ATTR_VERSION_MONOTONIC is kernel-only for now */
> + tmp.stx_attributes = stat->attributes & ~STATX_ATTR_VERSION_MONOTONIC;
> tmp.stx_nlink = stat->nlink;
> tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
> tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
> @@ -628,6 +636,11 @@ int do_statx(int dfd, struct filename *filename, unsigned int flags,
> if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
> return -EINVAL;
>
> + /* STATX_VERSION is kernel-only for now. Ignore requests
> + * from userland.
> + */
> + mask &= ~STATX_VERSION;
> +
> error = vfs_statx(dfd, filename, flags, &stat, mask);
> if (error)
> return error;
> diff --git a/include/linux/stat.h b/include/linux/stat.h
> index ff277ced50e9..4e9428d86a3a 100644
> --- a/include/linux/stat.h
> +++ b/include/linux/stat.h
> @@ -52,6 +52,15 @@ struct kstat {
> u64 mnt_id;
> u32 dio_mem_align;
> u32 dio_offset_align;
> + u64 version;
> };
>
> +/* These definitions are internal to the kernel for now. Mainly used by nfsd. */
> +
> +/* mask values */
> +#define STATX_VERSION 0x40000000U /* Want/got stx_change_attr */
> +
> +/* file attribute values */
> +#define STATX_ATTR_VERSION_MONOTONIC 0x8000000000000000ULL /* version monotonically increases */
> +
> #endif
> --
> 2.37.3
>
>
next prev parent reply other threads:[~2022-10-03 23:14 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-30 11:18 [PATCH v6 0/9] vfs/nfsd: clean up handling of i_version counter Jeff Layton
2022-09-30 11:18 ` [PATCH v6 1/9] iversion: move inode_query_iversion to libfs.c Jeff Layton
2022-10-03 23:05 ` NeilBrown
2022-09-30 11:18 ` [PATCH v6 2/9] iversion: clarify when the i_version counter must be updated Jeff Layton
2022-10-03 23:10 ` NeilBrown
2022-10-04 9:53 ` Jeff Layton
2022-09-30 11:18 ` [PATCH v6 3/9] vfs: plumb i_version handling into struct kstat Jeff Layton
2022-10-03 23:14 ` NeilBrown [this message]
2022-09-30 11:18 ` [PATCH v6 4/9] nfs: report the inode version in getattr if requested Jeff Layton
2022-10-03 23:29 ` NeilBrown
2022-10-04 9:43 ` Jeff Layton
2022-10-04 22:27 ` NeilBrown
2022-09-30 11:18 ` [PATCH v6 5/9] ceph: " Jeff Layton
2022-09-30 11:18 ` [PATCH v6 6/9] nfsd: use the getattr operation to fetch i_version Jeff Layton
2022-09-30 14:34 ` Chuck Lever III
2022-09-30 22:32 ` Dave Chinner
2022-10-03 23:39 ` NeilBrown
2022-10-05 10:06 ` Jeff Layton
2022-10-05 13:33 ` Chuck Lever III
2022-10-05 13:34 ` Trond Myklebust
2022-10-05 13:57 ` Jeff Layton
2022-10-05 21:14 ` NeilBrown
2022-10-06 11:15 ` Jeff Layton
2022-10-06 21:17 ` Dave Chinner
2022-09-30 11:18 ` [PATCH v6 7/9] vfs: expose STATX_VERSION to userland Jeff Layton
2022-10-03 23:42 ` NeilBrown
2022-10-05 10:08 ` Jeff Layton
2022-09-30 11:18 ` [PATCH v6 8/9] vfs: update times after copying data in __generic_file_write_iter Jeff Layton
2022-10-01 20:39 ` kernel test robot
2022-10-01 21:00 ` kernel test robot
2022-10-02 7:08 ` Amir Goldstein
2022-10-03 13:01 ` Jeff Layton
2022-10-03 13:52 ` Amir Goldstein
2022-10-03 22:56 ` NeilBrown
2022-10-05 16:40 ` Jeff Layton
2022-10-05 21:40 ` NeilBrown
2022-09-30 11:18 ` [PATCH v6 9/9] ext4: update times after I/O in write codepaths Jeff Layton
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