From: "J. Bruce Fields" <bfields@redhat.com>
To: Jeff Layton <jlayton@kernel.org>
Cc: Daire Byrne <daire@dneg.com>,
Trond Myklebust <trondmy@hammerspace.com>,
linux-cachefs <linux-cachefs@redhat.com>,
linux-nfs <linux-nfs@vger.kernel.org>,
"J. Bruce Fields" <bfields@redhat.com>
Subject: [PATCH 6/8] nfsd: move change attribute generation to filesystem
Date: Fri, 20 Nov 2020 17:39:18 -0500 [thread overview]
Message-ID: <1605911960-12516-6-git-send-email-bfields@redhat.com> (raw)
In-Reply-To: <1605911960-12516-1-git-send-email-bfields@redhat.com>
From: "J. Bruce Fields" <bfields@redhat.com>
After this, only filesystems lacking change attribute support will leave
the fetch_iversion export op NULL.
This seems cleaner to me, and will allow some minor optimizations in the
nfsd code.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
fs/btrfs/export.c | 2 ++
fs/ext4/super.c | 9 +++++++++
fs/nfsd/nfs4xdr.c | 2 +-
fs/nfsd/nfsfh.h | 25 +++----------------------
fs/nfsd/xdr4.h | 4 +++-
fs/xfs/xfs_export.c | 2 ++
include/linux/iversion.h | 26 ++++++++++++++++++++++++++
7 files changed, 46 insertions(+), 24 deletions(-)
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 1a8d419d9e1f..ece32440999a 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -7,6 +7,7 @@
#include "btrfs_inode.h"
#include "print-tree.h"
#include "export.h"
+#include <linux/iversion.h>
#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \
parent_objectid) / 4)
@@ -279,4 +280,5 @@ const struct export_operations btrfs_export_ops = {
.fh_to_parent = btrfs_fh_to_parent,
.get_parent = btrfs_get_parent,
.get_name = btrfs_get_name,
+ .fetch_iversion = generic_fetch_iversion,
};
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ef4734b40e2a..a4f48273d435 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1685,11 +1685,20 @@ static const struct super_operations ext4_sops = {
.bdev_try_to_free_page = bdev_try_to_free_page,
};
+static u64 ext4_fetch_iversion(struct inode *inode)
+{
+ if (IS_I_VERSION(inode))
+ return generic_fetch_iversion(inode);
+ else
+ return time_to_chattr(&inode->i_ctime);
+}
+
static const struct export_operations ext4_export_ops = {
.fh_to_dentry = ext4_fh_to_dentry,
.fh_to_parent = ext4_fh_to_parent,
.get_parent = ext4_get_parent,
.commit_metadata = ext4_nfs_commit_metadata,
+ .fetch_iversion = ext4_fetch_iversion,
};
enum {
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 18c912930947..182190684792 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3187,7 +3187,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
p = xdr_reserve_space(xdr, 4);
if (!p)
goto out_resource;
- if (IS_I_VERSION(d_inode(dentry)))
+ if (IS_I_VERSION(d_inode(dentry))
*p++ = cpu_to_be32(NFS4_CHANGE_TYPE_IS_MONOTONIC_INCR);
else
*p++ = cpu_to_be32(NFS4_CHANGE_TYPE_IS_TIME_METADATA);
diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 2656a3464c6c..ac3e309d7339 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -46,8 +46,8 @@ typedef struct svc_fh {
struct timespec64 fh_pre_mtime; /* mtime before oper */
struct timespec64 fh_pre_ctime; /* ctime before oper */
/*
- * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
- * to find out if it is valid.
+ * pre-op nfsv4 change attr: note must check for fetch_iversion
+ * op to find out if it is valid.
*/
u64 fh_pre_change;
@@ -246,31 +246,12 @@ fh_clear_wcc(struct svc_fh *fhp)
fhp->fh_pre_saved = false;
}
-/*
- * We could use i_version alone as the change attribute. However,
- * i_version can go backwards after a reboot. On its own that doesn't
- * necessarily cause a problem, but if i_version goes backwards and then
- * is incremented again it could reuse a value that was previously used
- * before boot, and a client who queried the two values might
- * incorrectly assume nothing changed.
- *
- * By using both ctime and the i_version counter we guarantee that as
- * long as time doesn't go backwards we never reuse an old value.
- */
static inline u64 nfsd4_change_attribute(struct kstat *stat,
struct inode *inode)
{
if (inode->i_sb->s_export_op->fetch_iversion)
return inode->i_sb->s_export_op->fetch_iversion(inode);
- else if (IS_I_VERSION(inode)) {
- u64 chattr;
-
- chattr = stat->ctime.tv_sec;
- chattr <<= 30;
- chattr += stat->ctime.tv_nsec;
- chattr += inode_query_iversion(inode);
- return chattr;
- } else
+ else
return time_to_chattr(&stat->ctime);
}
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 9c2d942d055d..f0c8fbe704a2 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -761,10 +761,12 @@ void warn_on_nonidempotent_op(struct nfsd4_op *op);
static inline void
set_change_info(struct nfsd4_change_info *cinfo, struct svc_fh *fhp)
{
+ struct inode *inode = d_inode(fhp->fh_dentry);
+
BUG_ON(!fhp->fh_pre_saved);
cinfo->atomic = (u32)fhp->fh_post_saved;
- if (IS_I_VERSION(d_inode(fhp->fh_dentry))) {
+ if (inode->i_sb->s_export_op->fetch_iversion) {
cinfo->before_change = fhp->fh_pre_change;
cinfo->after_change = fhp->fh_post_change;
} else {
diff --git a/fs/xfs/xfs_export.c b/fs/xfs/xfs_export.c
index 465fd9e048d4..b950fac3d7df 100644
--- a/fs/xfs/xfs_export.c
+++ b/fs/xfs/xfs_export.c
@@ -16,6 +16,7 @@
#include "xfs_inode_item.h"
#include "xfs_icache.h"
#include "xfs_pnfs.h"
+#include <linux/iversion.h>
/*
* Note that we only accept fileids which are long enough rather than allow
@@ -234,4 +235,5 @@ const struct export_operations xfs_export_operations = {
.map_blocks = xfs_fs_map_blocks,
.commit_blocks = xfs_fs_commit_blocks,
#endif
+ .fetch_iversion = generic_fetch_iversion,
};
diff --git a/include/linux/iversion.h b/include/linux/iversion.h
index 3bfebde5a1a6..ded74523c8a6 100644
--- a/include/linux/iversion.h
+++ b/include/linux/iversion.h
@@ -328,6 +328,32 @@ inode_query_iversion(struct inode *inode)
return cur >> I_VERSION_QUERIED_SHIFT;
}
+/*
+ * We could use i_version alone as the NFSv4 change attribute. However,
+ * i_version can go backwards after a reboot. On its own that doesn't
+ * necessarily cause a problem, but if i_version goes backwards and then
+ * is incremented again it could reuse a value that was previously used
+ * before boot, and a client who queried the two values might
+ * incorrectly assume nothing changed.
+ *
+ * By using both ctime and the i_version counter we guarantee that as
+ * long as time doesn't go backwards we never reuse an old value.
+ *
+ * A filesystem that has an on-disk boot counter or similar might prefer
+ * to use that to avoid the risk of the change attribute going backwards
+ * if system time is set backwards.
+ */
+static inline u64 generic_fetch_iversion(struct inode *inode)
+{
+ u64 chattr;
+
+ chattr = inode->i_ctime.tv_sec;
+ chattr <<= 30;
+ chattr += inode->i_ctime.tv_nsec;
+ chattr += inode_query_iversion(inode);
+ return chattr;
+}
+
/*
* For filesystems without any sort of change attribute, the best we can
* do is fake one up from the ctime:
--
2.28.0
next prev parent reply other threads:[~2020-11-20 22:39 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 17:31 Adventures in NFS re-exporting Daire Byrne
2020-09-08 9:40 ` Mkrtchyan, Tigran
2020-09-08 11:06 ` Daire Byrne
2020-09-15 17:21 ` J. Bruce Fields
2020-09-15 19:59 ` Trond Myklebust
2020-09-16 16:01 ` Daire Byrne
2020-10-19 16:19 ` Daire Byrne
2020-10-19 17:53 ` [PATCH 0/2] Add NFSv3 emulation of the lookupp operation trondmy
2020-10-19 17:53 ` [PATCH 1/2] NFSv3: Refactor nfs3_proc_lookup() to split out the dentry trondmy
2020-10-19 17:53 ` [PATCH 2/2] NFSv3: Add emulation of the lookupp() operation trondmy
2020-10-19 20:05 ` [PATCH v2 0/2] Add NFSv3 emulation of the lookupp operation trondmy
2020-10-19 20:05 ` [PATCH v2 1/2] NFSv3: Refactor nfs3_proc_lookup() to split out the dentry trondmy
2020-10-19 20:05 ` [PATCH v2 2/2] NFSv3: Add emulation of the lookupp() operation trondmy
2020-10-20 18:37 ` [PATCH v3 0/3] Add NFSv3 emulation of the lookupp operation trondmy
2020-10-20 18:37 ` [PATCH v3 1/3] NFSv3: Refactor nfs3_proc_lookup() to split out the dentry trondmy
2020-10-20 18:37 ` [PATCH v3 2/3] NFSv3: Add emulation of the lookupp() operation trondmy
2020-10-20 18:37 ` [PATCH v3 3/3] NFSv4: Observe the NFS_MOUNT_SOFTREVAL flag in _nfs4_proc_lookupp trondmy
2020-10-21 9:33 ` Adventures in NFS re-exporting Daire Byrne
2020-11-09 16:02 ` bfields
2020-11-12 13:01 ` Daire Byrne
2020-11-12 13:57 ` bfields
2020-11-12 18:33 ` Daire Byrne
2020-11-12 20:55 ` bfields
2020-11-12 23:05 ` Daire Byrne
2020-11-13 14:50 ` bfields
2020-11-13 22:26 ` bfields
2020-11-14 12:57 ` Daire Byrne
2020-11-16 15:18 ` bfields
2020-11-16 15:53 ` bfields
2020-11-16 19:21 ` Daire Byrne
2020-11-16 15:29 ` Jeff Layton
2020-11-16 15:56 ` bfields
2020-11-16 16:03 ` Jeff Layton
2020-11-16 16:14 ` bfields
2020-11-16 16:38 ` Jeff Layton
2020-11-16 19:03 ` bfields
2020-11-16 20:03 ` Jeff Layton
2020-11-17 3:16 ` bfields
2020-11-17 3:18 ` [PATCH 1/4] nfsd: move fill_{pre,post}_wcc to nfsfh.c J. Bruce Fields
2020-11-17 3:18 ` [PATCH 2/4] nfsd: pre/post attr is using wrong change attribute J. Bruce Fields
2020-11-17 12:34 ` Jeff Layton
2020-11-17 15:26 ` J. Bruce Fields
2020-11-17 15:34 ` Jeff Layton
2020-11-20 22:38 ` J. Bruce Fields
2020-11-20 22:39 ` [PATCH 1/8] nfsd: only call inode_query_iversion in the I_VERSION case J. Bruce Fields
2020-11-20 22:39 ` [PATCH 2/8] nfsd: simplify nfsd4_change_info J. Bruce Fields
2020-11-20 22:39 ` [PATCH 3/8] nfsd: minor nfsd4_change_attribute cleanup J. Bruce Fields
2020-11-21 0:34 ` Jeff Layton
2020-11-20 22:39 ` [PATCH 4/8] nfsd4: don't query change attribute in v2/v3 case J. Bruce Fields
2020-11-20 22:39 ` [PATCH 5/8] nfs: use change attribute for NFS re-exports J. Bruce Fields
2020-11-20 22:39 ` J. Bruce Fields [this message]
2020-11-21 0:58 ` [PATCH 6/8] nfsd: move change attribute generation to filesystem Jeff Layton
2020-11-21 1:01 ` J. Bruce Fields
2020-11-21 13:00 ` Jeff Layton
2020-11-20 22:39 ` [PATCH 7/8] nfsd: skip some unnecessary stats in the v4 case J. Bruce Fields
2020-11-20 22:39 ` [PATCH 8/8] Revert "nfsd4: support change_attr_type attribute" J. Bruce Fields
2020-11-20 22:44 ` [PATCH 2/4] nfsd: pre/post attr is using wrong change attribute J. Bruce Fields
2020-11-21 1:03 ` Jeff Layton
2020-11-21 21:44 ` Daire Byrne
2020-11-22 0:02 ` bfields
2020-11-22 1:55 ` Daire Byrne
2020-11-22 3:03 ` bfields
2020-11-23 20:07 ` Daire Byrne
2020-11-17 15:25 ` J. Bruce Fields
2020-11-17 3:18 ` [PATCH 3/4] nfs: don't mangle i_version on NFS J. Bruce Fields
2020-11-17 12:27 ` Jeff Layton
2020-11-17 14:14 ` J. Bruce Fields
2020-11-17 3:18 ` [PATCH 4/4] nfs: support i_version in the NFSv4 case J. Bruce Fields
2020-11-17 12:34 ` Jeff Layton
2020-11-24 20:35 ` Adventures in NFS re-exporting Daire Byrne
2020-11-24 21:15 ` bfields
2020-11-24 22:15 ` Frank Filz
2020-11-25 14:47 ` 'bfields'
2020-11-25 16:25 ` Frank Filz
2020-11-25 19:03 ` 'bfields'
2020-11-26 0:04 ` Frank Filz
2020-11-25 17:14 ` Daire Byrne
2020-11-25 19:31 ` bfields
2020-12-03 12:20 ` Daire Byrne
2020-12-03 18:51 ` bfields
2020-12-03 20:27 ` Trond Myklebust
2020-12-03 21:13 ` bfields
2020-12-03 21:32 ` Frank Filz
2020-12-03 21:34 ` Trond Myklebust
2020-12-03 21:45 ` Frank Filz
2020-12-03 21:57 ` Trond Myklebust
2020-12-03 22:04 ` bfields
2020-12-03 22:14 ` Trond Myklebust
2020-12-03 22:39 ` Frank Filz
2020-12-03 22:50 ` Trond Myklebust
2020-12-03 23:34 ` Frank Filz
2020-12-03 22:44 ` bfields
2020-12-03 21:54 ` bfields
2020-12-03 22:45 ` bfields
2020-12-03 22:53 ` Trond Myklebust
2020-12-03 23:16 ` bfields
2020-12-03 23:28 ` Frank Filz
2020-12-04 1:02 ` Trond Myklebust
2020-12-04 1:41 ` bfields
2020-12-04 2:27 ` Trond Myklebust
2020-09-17 16:01 ` Daire Byrne
2020-09-17 19:09 ` bfields
2020-09-17 20:23 ` Frank van der Linden
2020-09-17 21:57 ` bfields
2020-09-19 11:08 ` Daire Byrne
2020-09-22 16:43 ` Chuck Lever
2020-09-23 20:25 ` Daire Byrne
2020-09-23 21:01 ` Frank van der Linden
2020-09-26 9:00 ` Daire Byrne
2020-09-28 15:49 ` Frank van der Linden
2020-09-28 16:08 ` Chuck Lever
2020-09-28 17:42 ` Frank van der Linden
2020-09-22 12:31 ` Daire Byrne
2020-09-22 13:52 ` Trond Myklebust
2020-09-23 12:40 ` J. Bruce Fields
2020-09-23 13:09 ` Trond Myklebust
2020-09-23 17:07 ` bfields
2020-09-30 19:30 ` [Linux-cachefs] " Jeff Layton
2020-10-01 0:09 ` Daire Byrne
2020-10-01 10:36 ` Jeff Layton
2020-10-01 12:38 ` Trond Myklebust
2020-10-01 16:39 ` Jeff Layton
2020-10-05 12:54 ` Daire Byrne
2020-10-13 9:59 ` Daire Byrne
2020-10-01 18:41 ` J. Bruce Fields
2020-10-01 19:24 ` Trond Myklebust
2020-10-01 19:26 ` bfields
2020-10-01 19:29 ` Trond Myklebust
2020-10-01 19:51 ` bfields
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