NFS: Improve handling of directory verifiers

If the server insists on using the readdir verifiers in order to allow
cookies to expire, then we should ensure that we cache the verifier
with the cookie, so that we can return an error if the application
tries to use the expired cookie.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 3b44bef3a1b44676ef1b0e1278cac8a10e9bab6c..454377228167b8b4a01bffd5f937ca95af4d2a1c 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -155,6 +155,7 @@ struct nfs_readdir_descriptor {
        loff_t          current_index;
        loff_t          prev_index;
 
+       __be32          verf[NFS_DIR_VERIFIER_SIZE];
        unsigned long   dir_verifier;
        unsigned long   timestamp;
        unsigned long   gencount;
@@ -466,15 +467,15 @@ static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc)
 
 /* Fill a page with xdr information before transferring to the cache page */
 static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
-                                 u64 cookie, struct page **pages,
-                                 size_t bufsize)
+                                 __be32 *verf, u64 cookie,
+                                 struct page **pages, size_t bufsize,
+                                 __be32 *verf_res)
 {
        struct inode *inode = file_inode(desc->file);
-       __be32 verf_res[2];
        struct nfs_readdir_arg arg = {
                .dentry = file_dentry(desc->file),
                .cred = desc->file->f_cred,
-               .verf = NFS_I(inode)->cookieverf,
+               .verf = verf,
                .cookie = cookie,
                .pages = pages,
                .page_len = bufsize,
@@ -503,8 +504,6 @@ static int nfs_readdir_xdr_filler(struct nfs_readdir_descriptor *desc,
        }
        desc->timestamp = timestamp;
        desc->gencount = gencount;
-       memcpy(NFS_I(inode)->cookieverf, res.verf,
-              sizeof(NFS_I(inode)->cookieverf));
 error:
        return error;
 }
@@ -770,11 +769,13 @@ out_freepages:
 }
 
 static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc,
-                                   struct page *page, struct inode *inode)
+                                   struct page *page, __be32 *verf_arg,
+                                   __be32 *verf_res)
 {
        struct page **pages;
        struct nfs_entry *entry;
        size_t array_size;
+       struct inode *inode = file_inode(desc->file);
        size_t dtsize = NFS_SERVER(inode)->dtsize;
        int status = -ENOMEM;
 
@@ -801,8 +802,9 @@ static int nfs_readdir_xdr_to_array(struct nfs_readdir_descriptor *desc,
 
        do {
                unsigned int pglen;
-               status = nfs_readdir_xdr_filler(desc, entry->cookie,
-                                               pages, dtsize);
+               status = nfs_readdir_xdr_filler(desc, verf_arg, entry->cookie,
+                                               pages, dtsize,
+                                               verf_res);
                if (status < 0)
                        break;
 
@@ -854,13 +856,15 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
 {
        struct inode *inode = file_inode(desc->file);
        struct nfs_inode *nfsi = NFS_I(inode);
+       __be32 verf[NFS_DIR_VERIFIER_SIZE];
        int res;
 
        desc->page = nfs_readdir_page_get_cached(desc);
        if (!desc->page)
                return -ENOMEM;
        if (nfs_readdir_page_needs_filling(desc->page)) {
-               res = nfs_readdir_xdr_to_array(desc, desc->page, inode);
+               res = nfs_readdir_xdr_to_array(desc, desc->page,
+                                              nfsi->cookieverf, verf);
                if (res < 0) {
                        nfs_readdir_page_unlock_and_put_cached(desc);
                        if (res == -EBADCOOKIE || res == -ENOTSYNC) {
@@ -870,6 +874,7 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
                        }
                        return res;
                }
+               memcpy(nfsi->cookieverf, verf, sizeof(nfsi->cookieverf));
        }
        res = nfs_readdir_search_array(desc);
        if (res == 0) {
@@ -902,6 +907,7 @@ static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc)
 static void nfs_do_filldir(struct nfs_readdir_descriptor *desc)
 {
        struct file     *file = desc->file;
+       struct nfs_inode *nfsi = NFS_I(file_inode(file));
        struct nfs_cache_array *array;
        unsigned int i = 0;
 
@@ -915,6 +921,7 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc)
                        desc->eof = true;
                        break;
                }
+               memcpy(desc->verf, nfsi->cookieverf, sizeof(desc->verf));
                if (i < (array->size-1))
                        desc->dir_cookie = array->array[i+1].cookie;
                else
@@ -949,8 +956,8 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc)
 static int uncached_readdir(struct nfs_readdir_descriptor *desc)
 {
        struct page     *page = NULL;
+       __be32          verf[NFS_DIR_VERIFIER_SIZE];
        int             status;
-       struct inode *inode = file_inode(desc->file);
 
        dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
                        (unsigned long long)desc->dir_cookie);
@@ -967,7 +974,7 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc)
        desc->duped = 0;
 
        nfs_readdir_page_init_array(page, desc->dir_cookie);
-       status = nfs_readdir_xdr_to_array(desc, page, inode);
+       status = nfs_readdir_xdr_to_array(desc, page, desc->verf, verf);
        if (status < 0)
                goto out_release;
 
@@ -1023,6 +1030,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
        desc->dup_cookie = dir_ctx->dup_cookie;
        desc->duped = dir_ctx->duped;
        desc->attr_gencount = dir_ctx->attr_gencount;
+       memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf));
        spin_unlock(&file->f_lock);
 
        do {
@@ -1061,6 +1069,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
        dir_ctx->dup_cookie = desc->dup_cookie;
        dir_ctx->duped = desc->duped;
        dir_ctx->attr_gencount = desc->attr_gencount;
+       memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf));
        spin_unlock(&file->f_lock);
 
        kfree(desc);
@@ -1101,6 +1110,8 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
                        dir_ctx->dir_cookie = offset;
                else
                        dir_ctx->dir_cookie = 0;
+               if (offset == 0)
+                       memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf));
                dir_ctx->duped = 0;
        }
        spin_unlock(&filp->f_lock);

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index aa6493905bbe87f9445c44133f27e564ebbbb8c8..9b765a900b2894aab55404b9f0ed6608823c7581 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -229,7 +229,6 @@ static void nfs_zap_caches_locked(struct inode *inode)
        nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
        nfsi->attrtimeo_timestamp = jiffies;
 
-       memset(NFS_I(inode)->cookieverf, 0, sizeof(NFS_I(inode)->cookieverf));
        if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) {
                nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATTR
                                        | NFS_INO_INVALID_DATA
@@ -1237,7 +1236,6 @@ EXPORT_SYMBOL_GPL(nfs_revalidate_inode);
 
 static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
 {
-       struct nfs_inode *nfsi = NFS_I(inode);
        int ret;
 
        if (mapping->nrpages != 0) {
@@ -1250,11 +1248,6 @@ static int nfs_invalidate_mapping(struct inode *inode, struct address_space *map
                if (ret < 0)
                        return ret;
        }
-       if (S_ISDIR(inode->i_mode)) {
-               spin_lock(&inode->i_lock);
-               memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
-               spin_unlock(&inode->i_lock);
-       }
        nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
        nfs_fscache_wait_on_invalidate(inode);
 

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index dd6b463dda809784e0563f5b0fc695e2a36e885c..681ed98e4ba8e54de34ec917774187b1aabf37e9 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -45,6 +45,11 @@
  */
 #define NFS_RPC_SWAPFLAGS              (RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS)
 
+/*
+ * Size of the NFS directory verifier
+ */
+#define NFS_DIR_VERIFIER_SIZE          2
+
 /*
  * NFSv3/v4 Access mode cache entry
  */
@@ -89,6 +94,7 @@ struct nfs_open_context {
 struct nfs_open_dir_context {
        struct list_head list;
        unsigned long attr_gencount;
+       __be32  verf[NFS_DIR_VERIFIER_SIZE];
        __u64 dir_cookie;
        __u64 dup_cookie;
        signed char duped;
@@ -156,7 +162,7 @@ struct nfs_inode {
         * This is the cookie verifier used for NFSv3 readdir
         * operations
         */
-       __be32                  cookieverf[2];
+       __be32                  cookieverf[NFS_DIR_VERIFIER_SIZE];
 
        atomic_long_t           nrequests;
        struct nfs_mds_commit_info commit_info;