linux-kernel - Re: [PATCH] cifs: Fix duplicate fscache cookie warnings

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Message-ID: <CAH2r5mujc2dPCTN15DqoDJXkg8wOUaZbpDZ562CHsStZmuAOUQ@mail.gmail.com>
Date: Wed, 27 Mar 2024 12:07:34 -0500
From: Steve French <smfrench@...il.com>
To: David Howells <dhowells@...hat.com>
Cc: Steve French <sfrench@...ba.org>, Shyam Prasad N <nspmangalore@...il.com>, 
	Rohith Surabattula <rohiths.msft@...il.com>, Jeff Layton <jlayton@...nel.org>, 
	Christian Brauner <brauner@...nel.org>, linux-cifs@...r.kernel.org, netfs@...ts.linux.dev, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cifs: Fix duplicate fscache cookie warnings

added to cifs-2.6.git (also added Fixes tag) pending testing

On Wed, Mar 27, 2024 at 10:00 AM David Howells <dhowells@...hat.com> wrote:
>
> fscache emits a lot of duplicate cookie warnings with cifs because the
> index key for the fscache cookies does not include everything that the
> cifs_find_inode() function does.  The latter is used with iget5_locked() to
> distinguish between inodes in the local inode cache.
>
> Fix this by adding the creation time and file type to the fscache cookie
> key.
>
> Additionally, add a couple of comments to note that if one is changed the
> other must be also.
>
> Signed-off-by: David Howells <dhowells@...hat.com>
> cc: Steve French <sfrench@...ba.org>
> cc: Shyam Prasad N <nspmangalore@...il.com>
> cc: Rohith Surabattula <rohiths.msft@...il.com>
> cc: Jeff Layton <jlayton@...nel.org>
> cc: linux-cifs@...r.kernel.org
> cc: netfs@...ts.linux.dev
> cc: linux-fsdevel@...r.kernel.org
> ---
>  fs/smb/client/fscache.c |   16 +++++++++++++++-
>  fs/smb/client/inode.c   |    2 ++
>  2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/fs/smb/client/fscache.c b/fs/smb/client/fscache.c
> index c4a3cb736881..340efce8f052 100644
> --- a/fs/smb/client/fscache.c
> +++ b/fs/smb/client/fscache.c
> @@ -12,6 +12,16 @@
>  #include "cifs_fs_sb.h"
>  #include "cifsproto.h"
>
> +/*
> + * Key for fscache inode.  [!] Contents must match comparisons in cifs_find_inode().
> + */
> +struct cifs_fscache_inode_key {
> +
> +       __le64  uniqueid;       /* server inode number */
> +       __le64  createtime;     /* creation time on server */
> +       u8      type;           /* S_IFMT file type */
> +} __packed;
> +
>  static void cifs_fscache_fill_volume_coherency(
>         struct cifs_tcon *tcon,
>         struct cifs_fscache_volume_coherency_data *cd)
> @@ -97,15 +107,19 @@ void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
>  void cifs_fscache_get_inode_cookie(struct inode *inode)
>  {
>         struct cifs_fscache_inode_coherency_data cd;
> +       struct cifs_fscache_inode_key key;
>         struct cifsInodeInfo *cifsi = CIFS_I(inode);
>         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
>         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
>
> +       key.uniqueid    = cpu_to_le64(cifsi->uniqueid);
> +       key.createtime  = cpu_to_le64(cifsi->createtime);
> +       key.type        = (inode->i_mode & S_IFMT) >> 12;
>         cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
>
>         cifsi->netfs.cache =
>                 fscache_acquire_cookie(tcon->fscache, 0,
> -                                      &cifsi->uniqueid, sizeof(cifsi->uniqueid),
> +                                      &key, sizeof(key),
>                                        &cd, sizeof(cd),
>                                        i_size_read(&cifsi->netfs.inode));
>         if (cifsi->netfs.cache)
> diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
> index d28ab0af6049..91b07ef9e25c 100644
> --- a/fs/smb/client/inode.c
> +++ b/fs/smb/client/inode.c
> @@ -1351,6 +1351,8 @@ cifs_find_inode(struct inode *inode, void *opaque)
>  {
>         struct cifs_fattr *fattr = opaque;
>
> +       /* [!] The compared values must be the same in struct cifs_fscache_inode_key. */
> +
>         /* don't match inode with different uniqueid */
>         if (CIFS_I(inode)->uniqueid != fattr->cf_uniqueid)
>                 return 0;
>
>


-- 
Thanks,

Steve