NFS: Add attribute update barriers to nfs_setattr_update_inode()

commit f044636d972246d451e06226cc1675d5da389762 upstream.

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>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index e5eb677ca9ce383f059066377c824996f60105d8..127a6d9d81b70cce8bbdd2f5d17399051c3de881 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -545,6 +545,7 @@ 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)
 {
@@ -554,11 +555,11 @@ static int nfs_vmtruncate(struct inode * inode, loff_t offset)
        if (err)
                goto out;
 
-       spin_lock(&inode->i_lock);
        i_size_write(inode, offset);
-       spin_unlock(&inode->i_lock);
 
+       spin_unlock(&inode->i_lock);
        truncate_pagecache(inode, offset);
+       spin_lock(&inode->i_lock);
 out:
        return err;
 }
@@ -571,10 +572,15 @@ 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. */
+       fattr->gencount = nfs_inc_attr_generation_counter();
+
+       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;
@@ -585,12 +591,13 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
                if ((attr->ia_valid & ATTR_GID) != 0)
                        inode->i_gid = attr->ia_gid;
                NFS_I(inode)->cache_validity |= 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 90cb10d7b6936d1fc478f46572728e65e3874f29..8ef5276776f96d0eaadcd99343a5de9a3bda1550 100644 (file)
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -136,7 +136,7 @@ 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 43c27110387ab142fda1a3512a0448d7ad8621f8..36a72b59d7c8dc23306287f54fe2d95657ca38cf 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2276,8 +2276,8 @@ 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);
                }
        }
@@ -3114,7 +3114,7 @@ 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 a8f57c728df561ac58e158c9fb46ca3b7c77004e..7ffaeffc1330ea558d8e4c4484142d775554cd91 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 a632498d42fa061fa9f4c85b91d10a27f53eedb4..f4bf1b59332773bbd4602950aece728b9dc7aad1 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -354,7 +354,7 @@ extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
 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);