On Fri, 5 Nov 2010 11:29:32 +0300
Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
> On strict cache mode when we close the last file handle of the inode we
> should invalidate it to prevent data coherency problem when we open it
> again but it has been modified by other clients.
>
> Signed-off-by: Pavel Shilovsky <piastryyy@xxxxxxxxx>
> ---
> fs/cifs/cifs_fs_sb.h | 1 +
> fs/cifs/file.c | 6 ++++++
> 2 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
> index e9a393c..be7b159 100644
> --- a/fs/cifs/cifs_fs_sb.h
> +++ b/fs/cifs/cifs_fs_sb.h
> @@ -40,6 +40,7 @@
> #define CIFS_MOUNT_FSCACHE 0x8000 /* local caching enabled */
> #define CIFS_MOUNT_MF_SYMLINKS 0x10000 /* Minshall+French Symlinks enabled */
> #define CIFS_MOUNT_MULTIUSER 0x20000 /* multiuser mount */
> +#define CIFS_MOUNT_STRICT_IO 0x40000 /* strict cache mode */
>
> struct cifs_sb_info {
> struct rb_root tlink_tree;
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 777e7f4..b36de2e 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -264,7 +264,9 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
> struct inode *inode = cifs_file->dentry->d_inode;
> struct cifsTconInfo *tcon = tlink_tcon(cifs_file->tlink);
> struct cifsInodeInfo *cifsi = CIFS_I(inode);
> + struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
> struct cifsLockInfo *li, *tmp;
> + bool last_open_file = false;
>
> spin_lock(&cifs_file_list_lock);
> if (--cifs_file->count > 0) {
> @@ -279,10 +281,14 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
> if (list_empty(&cifsi->openFileList)) {
> cFYI(1, "closing last open instance for inode %p",
> cifs_file->dentry->d_inode);
> + last_open_file = true;
> cifs_set_oplock_level(inode, 0);
> }
> spin_unlock(&cifs_file_list_lock);
>
> + if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) && last_open_file)
> + invalidate_remote_inode(inode);
> +
Now that I think about it...this looks racy. Suppose someone races in
after you set last_open_file, opens the file and does a write....
I think you'd be better served by setting the invalid_mapping flag on
the cifs_i instead and letting the normal revalidation codepath handle
this. The cache will then be invalidated the next time
cifs_revalidate_file/dentry is run.
> if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
> int xid, rc;
>
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