----- Original Message -----
> From: trondmy@xxxxxxxxxx
> To: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>
> Sent: Tuesday, 3 November, 2020 16:33:29
> Subject: [PATCH v2 16/16] NFS: Improve handling of directory verifiers
> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/dir.c | 35 +++++++++++++++++++++++------------
> fs/nfs/inode.c | 7 -------
> include/linux/nfs_fs.h | 8 +++++++-
> 3 files changed, 30 insertions(+), 20 deletions(-)
>
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 1c5a5f9cb228..0bd9cc625bdb 100644
> --- 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;
> @@ -467,15 +468,15 @@ 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,
> @@ -504,8 +505,6 @@ 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;
> }
> @@ -771,11 +770,13 @@ static struct page **nfs_readdir_alloc_pages(size_t
> npages)
> }
>
> 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;
>
> @@ -802,8 +803,9 @@ 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;
>
> @@ -855,13 +857,15 @@ 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) {
> @@ -871,6 +875,7 @@ 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) {
> @@ -903,6 +908,7 @@ 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;
>
> @@ -916,6 +922,7 @@ 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
> @@ -950,8 +957,8 @@ 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);
> @@ -968,7 +975,7 @@ 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;
>
> @@ -1024,6 +1031,7 @@ 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 {
> @@ -1062,6 +1070,7 @@ 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);
> @@ -1102,6 +1111,8 @@ 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 aa6493905bbe..9b765a900b28 100644
> --- 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 dd6b463dda80..681ed98e4ba8 100644
> --- 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];
Just for my education. Why we use 2x32 bit BE encoded ints instead of raw 8 bytes?
And if it's treaded as a number, as spec sometimes does ("The request's cookieverf
field should be set to 0"), then why it's not then __be64?
Tigran.
>
> atomic_long_t nrequests;
> struct nfs_mds_commit_info commit_info;
> --
> 2.28.0
