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Message-ID: <1311800051.25645.43.camel@lade.trondhjem.org>
Date: Wed, 27 Jul 2011 16:54:11 -0400
From: Trond Myklebust <Trond.Myklebust@...app.com>
To: Christoph Hellwig <hch@...radead.org>
Cc: Bryan Schumaker <bjschuma@...app.com>,
Justin Piszcz <jpiszcz@...idpixels.com>,
"J. Bruce Fields" <bfields@...ldses.org>,
linux-nfs@...r.kernel.org, linux-kernel@...r.kernel.org,
xfs@....sgi.com
Subject: Re: 2.6.xx: NFS: directory motion/cam2 contains a readdir loop
On Wed, 2011-07-27 at 16:37 -0400, Trond Myklebust wrote:
> On Wed, 2011-07-27 at 15:47 -0400, Christoph Hellwig wrote:
> > On Wed, Jul 27, 2011 at 03:44:20PM -0400, Justin Piszcz wrote:
> > >
> > >
> > > On Wed, 27 Jul 2011, Christoph Hellwig wrote:
> > >
> > > >On Wed, Jul 27, 2011 at 03:35:01PM -0400, Justin Piszcz wrote:
> > > >>Currently I do not see any dupes, however I have a script that moves
> > > >>images out of the directory once an hour:
> > > >>0 * * * * /usr/local/bin/move_to_old2.sh > /dev/null 2>&1
> > > >
> > > >Do you keep adding files to the directory while you move files out?
> > > Yes, otherwise there are too many files in the directory and viewers, e.g.,
> > > each geeqie (picture viewer) will use > 4-6GB of memory, so I try to keep
> > > it around 5,000 pictures or less.
> > >
> > > >What's the rate of additions/removals to the directory?
> > > Additions it depends, around 5,000 over a 12hr period, 416/hr, current:
> > >
> > > atom:/d1/motion# find cam1|wc
> > > 5215 5215 166853
> > > atom:/d1/motion# find cam2|wc
> > > 5069 5069 162181
> > > atom:/d1/motion# find cam3|wc
> > > 5594 5594 178981
> > > atom:/d1/motion#
> >
> > This sounds a lot like xfs simply filling up the directory index slots
> > of files that you just moved out with new files, and nfs falsely
> > claiming that this is a problem.
>
> Yep. There is an existing bugzilla report for this bug at
>
> https://bugzilla.kernel.org/show_bug.cgi?id=38572
>
> I have a preliminary patch there that attempts to turn off the loop
> detection when the directory is seen to change, however that patch still
> appears to have a bug in it, and I haven't had time to figure out what
> is wrong yet.
>
> Can you perhaps take a look, Bryan?
Actually, Justin, can you test the following slight variant on the patch
in the bugzilla?
8<---------------------------------------------------------
>From 13cf7def9f2d802c3ea300833ba7f88705279cb1 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@...app.com>
Date: Wed, 27 Jul 2011 16:51:56 -0400
Subject: [PATCH] NFS: Fix spurious readdir cookie loop messages
If the directory contents change, then we have to accept that the
file->f_pos value may shrink if we do a 'search-by-cookie'. In that
case, we should turn off the loop detection and let the NFS client
try to recover.
Reported-by: Petr Vandrovec <petr@...drovec.name>
Cc: stable@...nel.org [2.6.39]
Signed-off-by: Trond Myklebust <Trond.Myklebust@...app.com>
---
fs/nfs/dir.c | 25 ++++++++++++++++---------
include/linux/nfs_fs.h | 1 +
2 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 57f578e..73993b9 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -134,7 +134,7 @@ const struct inode_operations nfs4_dir_inode_operations = {
#endif /* CONFIG_NFS_V4 */
-static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct rpc_cred *cred)
+static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir, struct rpc_cred *cred)
{
struct nfs_open_dir_context *ctx;
ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
@@ -143,9 +143,10 @@ static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct rpc_cred *
ctx->dir_cookie = 0;
ctx->dup_cookie = 0;
ctx->cred = get_rpccred(cred);
- } else
- ctx = ERR_PTR(-ENOMEM);
- return ctx;
+ ctx->cache_change_attribute = nfs_save_change_attribute(dir);
+ return ctx;
+ }
+ return ERR_PTR(-ENOMEM);
}
static void put_nfs_open_dir_context(struct nfs_open_dir_context *ctx)
@@ -173,7 +174,7 @@ nfs_opendir(struct inode *inode, struct file *filp)
cred = rpc_lookup_cred();
if (IS_ERR(cred))
return PTR_ERR(cred);
- ctx = alloc_nfs_open_dir_context(cred);
+ ctx = alloc_nfs_open_dir_context(inode, cred);
if (IS_ERR(ctx)) {
res = PTR_ERR(ctx);
goto out;
@@ -323,7 +324,6 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
{
loff_t diff = desc->file->f_pos - desc->current_index;
unsigned int index;
- struct nfs_open_dir_context *ctx = desc->file->private_data;
if (diff < 0)
goto out_eof;
@@ -336,7 +336,6 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
index = (unsigned int)diff;
*desc->dir_cookie = array->array[index].cookie;
desc->cache_entry_index = index;
- ctx->duped = 0;
return 0;
out_eof:
desc->eof = 1;
@@ -349,12 +348,18 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
int i;
loff_t new_pos;
int status = -EAGAIN;
- struct nfs_open_dir_context *ctx = desc->file->private_data;
for (i = 0; i < array->size; i++) {
if (array->array[i].cookie == *desc->dir_cookie) {
+ struct inode *dir = desc->file->f_path.dentry->d_inode;
+ struct nfs_open_dir_context *ctx = desc->file->private_data;
+
new_pos = desc->current_index + i;
- if (new_pos < desc->file->f_pos) {
+ if (!nfs_verify_change_attribute(dir, ctx->cache_change_attribute)
+ || (NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATTR)) {
+ ctx->cache_change_attribute = nfs_save_change_attribute(dir);
+ ctx->duped = 0;
+ } else if (new_pos < desc->file->f_pos) {
ctx->dup_cookie = *desc->dir_cookie;
ctx->duped = 1;
}
@@ -805,6 +810,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
struct page *page = NULL;
int status;
struct inode *inode = desc->file->f_path.dentry->d_inode;
+ struct nfs_open_dir_context *ctx = desc->file->private_data;
dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
(unsigned long long)*desc->dir_cookie);
@@ -818,6 +824,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
desc->page_index = 0;
desc->last_cookie = *desc->dir_cookie;
desc->page = page;
+ ctx->duped = 0;
status = nfs_readdir_xdr_to_array(desc, page, inode);
if (status < 0)
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 8b579be..f45d712 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -99,6 +99,7 @@ struct nfs_open_context {
struct nfs_open_dir_context {
struct rpc_cred *cred;
+ unsigned long cache_change_attribute;
__u64 dir_cookie;
__u64 dup_cookie;
int duped;
--
1.7.6
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@...app.com
www.netapp.com
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