NFS: nfs_wcc_update_inode() should set nfsi->attr_gencount

If the call to nfs_wcc_update_inode() results in an attribute update, we
need to ensure that the inode's attr_gencount gets bumped too, otherwise
we are not protected against races with other GETATTR calls.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index d8512423ba7298ee56368fd27e42d4d01fd7cee2..1cc600e77bb43aa14ba3d1547d5780c2a0e7c0a5 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -881,9 +881,10 @@ out:
        return ret;
 }
 
-static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
+static unsigned long nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 {
        struct nfs_inode *nfsi = NFS_I(inode);
+       unsigned long ret = 0;
 
        if ((fattr->valid & NFS_ATTR_FATTR_PRECHANGE)
                        && (fattr->valid & NFS_ATTR_FATTR_CHANGE)
@@ -891,25 +892,32 @@ static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
                nfsi->change_attr = fattr->change_attr;
                if (S_ISDIR(inode->i_mode))
                        nfsi->cache_validity |= NFS_INO_INVALID_DATA;
+               ret |= NFS_INO_INVALID_ATTR;
        }
        /* If we have atomic WCC data, we may update some attributes */
        if ((fattr->valid & NFS_ATTR_FATTR_PRECTIME)
                        && (fattr->valid & NFS_ATTR_FATTR_CTIME)
-                       && timespec_equal(&inode->i_ctime, &fattr->pre_ctime))
-                       memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
+                       && timespec_equal(&inode->i_ctime, &fattr->pre_ctime)) {
+               memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
+               ret |= NFS_INO_INVALID_ATTR;
+       }
 
        if ((fattr->valid & NFS_ATTR_FATTR_PREMTIME)
                        && (fattr->valid & NFS_ATTR_FATTR_MTIME)
                        && timespec_equal(&inode->i_mtime, &fattr->pre_mtime)) {
-                       memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
-                       if (S_ISDIR(inode->i_mode))
-                               nfsi->cache_validity |= NFS_INO_INVALID_DATA;
+               memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
+               if (S_ISDIR(inode->i_mode))
+                       nfsi->cache_validity |= NFS_INO_INVALID_DATA;
+               ret |= NFS_INO_INVALID_ATTR;
        }
        if ((fattr->valid & NFS_ATTR_FATTR_PRESIZE)
                        && (fattr->valid & NFS_ATTR_FATTR_SIZE)
                        && i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size)
-                       && nfsi->npages == 0)
-                       i_size_write(inode, nfs_size_to_loff_t(fattr->size));
+                       && nfsi->npages == 0) {
+               i_size_write(inode, nfs_size_to_loff_t(fattr->size));
+               ret |= NFS_INO_INVALID_ATTR;
+       }
+       return ret;
 }
 
 /**
@@ -1223,7 +1231,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
                        | NFS_INO_REVAL_PAGECACHE);
 
        /* Do atomic weak cache consistency updates */
-       nfs_wcc_update_inode(inode, fattr);
+       invalid |= nfs_wcc_update_inode(inode, fattr);
 
        /* More cache consistency checks */
        if (fattr->valid & NFS_ATTR_FATTR_CHANGE) {