Re: [PATCH 1/2 v2] nfs: use change attribute for NFS re-exports
From: Chuck Lever <hidden>
Date: 2021-01-29 20:47:29
Also in:
linux-fsdevel
Hi Bruce-
On Jan 29, 2021, at 2:26 PM, J. Bruce Fields [off-list ref] wrote: From: "J. Bruce Fields" <redacted> When exporting NFS, we may as well use the real change attribute returned by the original server instead of faking up a change attribute from the ctime. Note we can't do that by setting I_VERSION--that would also turn on the logic in iversion.h which treats the lower bit specially, and that doesn't make sense for NFS. So instead we define a new export operation for filesystems like NFS that want to manage the change attribute themselves. Signed-off-by: J. Bruce Fields <redacted>
These two patches have replaced the v1 patches from last week in the for-next branch at git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git These are included provisionally while review and further testing is ongoing.
quoted hunk ↗ jump to hunk
--- fs/nfs/export.c | 18 ++++++++++++++++++ fs/nfsd/nfsfh.h | 5 ++++- include/linux/exportfs.h | 1 + 3 files changed, 23 insertions(+), 1 deletion(-)diff --git a/fs/nfs/export.c b/fs/nfs/export.c index 7412bb164fa7..f2b34cfe286c 100644 --- a/fs/nfs/export.c +++ b/fs/nfs/export.c@@ -167,10 +167,28 @@ nfs_get_parent(struct dentry *dentry)return parent; } +static u64 nfs_fetch_iversion(struct inode *inode) +{ + struct nfs_server *server = NFS_SERVER(inode); + + /* Is this the right call?: */ + nfs_revalidate_inode(server, inode); + /* + * Also, note we're ignoring any returned error. That seems to be + * the practice for cache consistency information elsewhere in + * the server, but I'm not sure why. + */ + if (server->nfs_client->rpc_ops->version >= 4) + return inode_peek_iversion_raw(inode); + else + return time_to_chattr(&inode->i_ctime); +} + const struct export_operations nfs_export_ops = { .encode_fh = nfs_encode_fh, .fh_to_dentry = nfs_fh_to_dentry, .get_parent = nfs_get_parent, + .fetch_iversion = nfs_fetch_iversion, .flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK| EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS| EXPORT_OP_NOATOMIC_ATTR,diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h index cb20c2cd3469..f58933519f38 100644 --- a/fs/nfsd/nfsfh.h +++ b/fs/nfsd/nfsfh.h@@ -12,6 +12,7 @@#include <linux/sunrpc/svc.h> #include <uapi/linux/nfsd/nfsfh.h> #include <linux/iversion.h> +#include <linux/exportfs.h> static inline __u32 ino_t_to_u32(ino_t ino) {@@ -264,7 +265,9 @@ fh_clear_wcc(struct svc_fh *fhp)static inline u64 nfsd4_change_attribute(struct kstat *stat, struct inode *inode) { - if (IS_I_VERSION(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;diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index 9f4d4bcbf251..fe848901fcc3 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h@@ -213,6 +213,7 @@ struct export_operations {bool write, u32 *device_generation); int (*commit_blocks)(struct inode *inode, struct iomap *iomaps, int nr_iomaps, struct iattr *iattr); + u64 (*fetch_iversion)(struct inode *); #define EXPORT_OP_NOWCC (0x1) /* don't collect v3 wcc data */ #define EXPORT_OP_NOSUBTREECHK (0x2) /* no subtree checking */ #define EXPORT_OP_CLOSE_BEFORE_UNLINK (0x4) /* close files before unlink */ -- 2.29.2
-- Chuck Lever