On Mar 8, 2014, at 8:22, Steve Dickson <SteveD@xxxxxxxxxx> wrote:
> Modern day kernel will no longer return all timeout
> errors instead the process spins endlessly in the kernel.
> This behavior will cause the foreground mount to hang, never
> allowing the mount to go into background.
>
> So this patch eliminates the foreground mount cause
> background mounts to go directly into background
>
> Signed-off-by: Steve Dickson <steved@xxxxxxxxxx>
> ---
> utils/mount/stropts.c | 31 ++++++++-----------------------
> 1 files changed, 8 insertions(+), 23 deletions(-)
>
> diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
> index a642394..92a7245 100644
> --- a/utils/mount/stropts.c
> +++ b/utils/mount/stropts.c
> @@ -913,28 +913,6 @@ static int nfsmount_fg(struct nfsmount_info *mi)
> }
>
> /*
> - * Handle "background" NFS mount [first try]
> - *
> - * Returns a valid mount command exit code.
> - *
> - * EX_BG should cause the caller to fork and invoke nfsmount_child.
> - */
> -static int nfsmount_parent(struct nfsmount_info *mi)
> -{
> - if (nfs_try_mount(mi))
> - return EX_SUCCESS;
> -
> - /* retry background mounts when the server is not up */
> - if (nfs_is_permanent_error(errno) && errno != EOPNOTSUPP) {
> - mount_error(mi->spec, mi->node, errno);
> - return EX_FAIL;
> - }
> -
> - sys_mount_errors(mi->hostname, errno, 1, 1);
> - return EX_BG;
> -}
> -
> -/*
> * Handle "background" NFS mount [retry daemon]
> *
> * Returns a valid mount command exit code: EX_SUCCESS if successful,
> @@ -982,7 +960,14 @@ static int nfsmount_child(struct nfsmount_info *mi)
> static int nfsmount_bg(struct nfsmount_info *mi)
> {
> if (!mi->child)
> - return nfsmount_parent(mi);
> + /*
> + * Modern day kernels no longer return all
> + * timeouts errors in all cases, instead
> + * the process spins in the kernel, which
> + * will hang a foreground mount. So background
> + * mounts have to go directly into background
> + */
> + return EX_BG;
> else
> return nfsmount_child(mi);
> }
Hi Steve,
Doesn’t this mean that ‘mount.nfs’ will no longer attempt to wait for the mount to complete? That’s why I suggested having the parent set a timer, and then waiting for whichever comes first out of SIGCHLD or SIGALRM (indicating either that the child mount process is done mounting or that the timeout occurred).
Cheers
Trond
_________________________________
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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