On Sat, 2021-03-13 at 04:38 +0000, Al Viro wrote:
> if we have mkdir request reported successful *and* simulating lookup
> gets us a non-directory (which is possible if another client has
> managed to get rmdir and create in between), the sane action is not
> to mangle ->i_mode of non-directory inode to S_IFDIR | mode, it's
> "report success and return with dentry negative unhashed" - that
> way the next lookup will do the right thing.
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> fs/cifs/inode.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index d46b36d52211..80c487fcf10e 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -1739,6 +1739,16 @@ cifs_mkdir_qinfo(struct inode *parent, struct dentry *dentry, umode_t mode,
> if (rc)
> return rc;
>
>
> + if (!S_ISDIR(inode->i_mode)) {
> + /*
> + * mkdir succeeded, but another client has managed to remove the
> + * sucker and replace it with non-directory. Return success,
> + * but don't leave the child in dcache.
> + */
> + iput(inode);
> + d_drop(dentry);
> + return 0;
> + }
> /*
> * setting nlink not necessary except in cases where we failed to get it
> * from the server or was set bogus. Also, since this is a brand new
> @@ -1790,7 +1800,7 @@ cifs_mkdir_qinfo(struct inode *parent, struct dentry *dentry, umode_t mode,
> }
> }
> d_instantiate(dentry, inode);
> - return rc;
> + return 0;
> }
>
>
> static int
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
