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>

1 files changed, 17 insertions, 9 deletions

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index d8512423ba72..1cc600e77bb4 100644
--- 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) {