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From: trondmy@kernel.org
To: linux-nfs@vger.kernel.org
Subject: [PATCH v2 16/16] NFS: Improve handling of directory verifiers
Date: Tue,  3 Nov 2020 10:33:29 -0500
Message-ID: <20201103153329.531942-17-trondmy@kernel.org> (raw)
In-Reply-To: <20201103153329.531942-16-trondmy@kernel.org>

From: Trond Myklebust <trond.myklebust@hammerspace.com>

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>
---
 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];
 
 	atomic_long_t		nrequests;
 	struct nfs_mds_commit_info commit_info;
-- 
2.28.0


  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-03 15:33 [PATCH v2 00/16] Readdir enhancements trondmy
2020-11-03 15:33 ` [PATCH v2 01/16] NFS: Ensure contents of struct nfs_open_dir_context are consistent trondmy
2020-11-03 15:33   ` [PATCH v2 02/16] NFS: Clean up readdir struct nfs_cache_array trondmy
2020-11-03 15:33     ` [PATCH v2 03/16] NFS: Clean up nfs_readdir_page_filler() trondmy
2020-11-03 15:33       ` [PATCH v2 04/16] NFS: Clean up directory array handling trondmy
2020-11-03 15:33         ` [PATCH v2 05/16] NFS: Don't discard readdir results trondmy
2020-11-03 15:33           ` [PATCH v2 06/16] NFS: Remove unnecessary kmap in nfs_readdir_xdr_to_array() trondmy
2020-11-03 15:33             ` [PATCH v2 07/16] NFS: Replace kmap() with kmap_atomic() in nfs_readdir_search_array() trondmy
2020-11-03 15:33               ` [PATCH v2 08/16] NFS: Simplify struct nfs_cache_array_entry trondmy
2020-11-03 15:33                 ` [PATCH v2 09/16] NFS: Support larger readdir buffers trondmy
2020-11-03 15:33                   ` [PATCH v2 10/16] NFS: More readdir cleanups trondmy
2020-11-03 15:33                     ` [PATCH v2 11/16] NFS: nfs_do_filldir() does not return a value trondmy
2020-11-03 15:33                       ` [PATCH v2 12/16] NFS: Reduce readdir stack usage trondmy
2020-11-03 15:33                         ` [PATCH v2 13/16] NFS: Cleanup to remove nfs_readdir_descriptor_t typedef trondmy
2020-11-03 15:33                           ` [PATCH v2 14/16] NFS: Allow the NFS generic code to pass in a verifier to readdir trondmy
2020-11-03 15:33                             ` [PATCH v2 15/16] NFS: Handle NFS4ERR_NOT_SAME and NFSERR_BADCOOKIE from readdir calls trondmy
2020-11-03 15:33                               ` trondmy [this message]
2020-11-04 10:12                                 ` [PATCH v2 16/16] NFS: Improve handling of directory verifiers Mkrtchyan, Tigran
2020-11-04 17:21                                   ` Trond Myklebust
2020-11-03 15:55           ` [PATCH v2 05/16] NFS: Don't discard readdir results Benjamin Coddington
2020-11-03 16:14             ` Trond Myklebust
2020-11-04 16:14 ` [PATCH v2 00/16] Readdir enhancements Benjamin Coddington
2020-11-04 17:04   ` Trond Myklebust
2020-11-04 17:19     ` Benjamin Coddington

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