NFS: Add attribute update barriers to nfs_setattr_update_inode()

Ensure that other operations which raced with our setattr RPC call
cannot revert the file attribute changes that were made on the server.
To do so, we artificially bump the attribute generation counter on
the inode so that all calls to nfs_fattr_init() that precede ours
will be dropped.

The motivation for the patch came from Chuck Lever's reports of readaheads
racing with truncate operations and causing the file size to be reverted.

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index b0cbc1ba82dab8ed82b707133d03845a9f72ef19..3a2d127de499fcbd72a50750523464473f477a46 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -556,6 +556,7 @@ EXPORT_SYMBOL_GPL(nfs_setattr);
  * This is a copy of the common vmtruncate, but with the locking
  * corrected to take into account the fact that NFS requires
  * inode->i_size to be updated under the inode->i_lock.
+ * Note: must be called with inode->i_lock held!
  */
 static int nfs_vmtruncate(struct inode * inode, loff_t offset)
 {
@@ -565,14 +566,14 @@ static int nfs_vmtruncate(struct inode * inode, loff_t offset)
        if (err)
                goto out;
 
-       spin_lock(&inode->i_lock);
        i_size_write(inode, offset);
        /* Optimisation */
        if (offset == 0)
                NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_DATA;
-       spin_unlock(&inode->i_lock);
 
+       spin_unlock(&inode->i_lock);
        truncate_pagecache(inode, offset);
+       spin_lock(&inode->i_lock);
 out:
        return err;
 }
@@ -585,10 +586,15 @@ out:
  * Note: we do this in the *proc.c in order to ensure that
  *       it works for things like exclusive creates too.
  */
-void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
+void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr,
+               struct nfs_fattr *fattr)
 {
+       /* Barrier: bump the attribute generation count. */
+       nfs_fattr_set_barrier(fattr);
+
+       spin_lock(&inode->i_lock);
+       NFS_I(inode)->attr_gencount = fattr->gencount;
        if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0) {
-               spin_lock(&inode->i_lock);
                if ((attr->ia_valid & ATTR_MODE) != 0) {
                        int mode = attr->ia_mode & S_IALLUGO;
                        mode |= inode->i_mode & ~S_IALLUGO;
@@ -600,12 +606,13 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
                        inode->i_gid = attr->ia_gid;
                nfs_set_cache_invalid(inode, NFS_INO_INVALID_ACCESS
                                | NFS_INO_INVALID_ACL);
-               spin_unlock(&inode->i_lock);
        }
        if ((attr->ia_valid & ATTR_SIZE) != 0) {
                nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC);
                nfs_vmtruncate(inode, attr->ia_size);
        }
+       nfs_update_inode(inode, fattr);
+       spin_unlock(&inode->i_lock);
 }
 EXPORT_SYMBOL_GPL(nfs_setattr_update_inode);
 

diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index 78e557c3ab87d014694e6e4098faefb20553f579..11109a137c0c8065232e48f09d3811d802258a8b 100644 (file)
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -138,7 +138,7 @@ nfs3_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
        nfs_fattr_init(fattr);
        status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
        if (status == 0)
-               nfs_setattr_update_inode(inode, sattr);
+               nfs_setattr_update_inode(inode, sattr, fattr);
        dprintk("NFS reply setattr: %d\n", status);
        return status;
 }

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4e41340e957d36f47b41c4f68c637d2439ef52e4..c499e02a58ca63ed7ec7f252d7807a03944001c9 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2416,8 +2416,8 @@ static int _nfs4_do_open(struct inode *dir,
                                opendata->o_res.f_attr, sattr,
                                state, label, olabel);
                if (status == 0) {
-                       nfs_setattr_update_inode(state->inode, sattr);
-                       nfs_post_op_update_inode(state->inode, opendata->o_res.f_attr);
+                       nfs_setattr_update_inode(state->inode, sattr,
+                                       opendata->o_res.f_attr);
                        nfs_setsecurity(state->inode, opendata->o_res.f_attr, olabel);
                }
        }
@@ -3291,7 +3291,7 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 
        status = nfs4_do_setattr(inode, cred, fattr, sattr, state, NULL, label);
        if (status == 0) {
-               nfs_setattr_update_inode(inode, sattr);
+               nfs_setattr_update_inode(inode, sattr, fattr);
                nfs_setsecurity(inode, fattr, label);
        }
        nfs4_label_free(label);

diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index b09cc23d6f433bc5ea8aff6cfe68c3910c4f8319..6202bc0f11bb2bfb9ecdb08a1f21967a26c1e501 100644 (file)
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -139,7 +139,7 @@ nfs_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
        nfs_fattr_init(fattr);
        status = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
        if (status == 0)
-               nfs_setattr_update_inode(inode, sattr);
+               nfs_setattr_update_inode(inode, sattr, fattr);
        dprintk("NFS reply setattr: %d\n", status);
        return status;
 }

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 3a4ffb5856cd6a2cf298c4962411857ceb0c44ab..f26e64e0aff846d262d0631c07bbf69103bc8549 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -356,7 +356,7 @@ extern int nfs_revalidate_inode_rcu(struct nfs_server *server, struct inode *ino
 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
 extern int nfs_setattr(struct dentry *, struct iattr *);
-extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
+extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);
 extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,
                                struct nfs4_label *label);
 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);