From 70b87f77294d16d3e567056ba4c9ee2b091a5b50 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 30 Nov 2020 17:46:14 -0500 Subject: nfsd: only call inode_query_iversion in the I_VERSION case inode_query_iversion() can modify i_version. Depending on the exported filesystem, that may not be safe. For example, if you're re-exporting NFS, NFS stores the server's change attribute in i_version and does not expect it to be modified locally. This has been observed causing unnecessary cache invalidations. The way a filesystem indicates that it's OK to call inode_query_iverson() is by setting SB_I_VERSION. So, move the I_VERSION check out of encode_change(), where it's used only in GETATTR responses, to nfsd4_change_attribute(), which is also called for pre- and post- operation attributes. (Note we could also pull the NFSEXP_V4ROOT case into nfsd4_change_attribute() as well. That would actually be a no-op, since pre/post attrs are only used for metadata-modifying operations, and V4ROOT exports are read-only. But we might make the change in the future just for simplicity.) Reported-by: Daire Byrne Signed-off-by: J. Bruce Fields Signed-off-by: Chuck Lever --- fs/nfsd/nfs3xdr.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'fs/nfsd/nfs3xdr.c') diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index a6718b952975..4599de24ef1a 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -291,14 +291,13 @@ void fill_post_wcc(struct svc_fh *fhp) printk("nfsd: inode locked twice during operation.\n"); err = fh_getattr(fhp, &fhp->fh_post_attr); - fhp->fh_post_change = nfsd4_change_attribute(&fhp->fh_post_attr, - d_inode(fhp->fh_dentry)); if (err) { fhp->fh_post_saved = false; - /* Grab the ctime anyway - set_change_info might use it */ fhp->fh_post_attr.ctime = d_inode(fhp->fh_dentry)->i_ctime; } else fhp->fh_post_saved = true; + fhp->fh_post_change = nfsd4_change_attribute(&fhp->fh_post_attr, + d_inode(fhp->fh_dentry)); } /* -- cgit v1.2.3