| Message ID | 20220930111840.10695-4-jlayton@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfs/nfsd: clean up handling of i_version counter | expand |
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 > >
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