Re: [PATCH] Handle ENOMEM during log initialisation

[Christoph Hellwig <hch@infradead.org>]

On Wed, Oct 22, 2008 at 05:10:02PM +1100, Dave Chinner wrote:
> XFS: handle memory allocation failures during log initialisation
> 
> When there is no memory left in the system, xfs_buf_get_noaddr()
> can fail. If this happens at mount time during xlog_alloc_log()
> we fail to catch the error and oops.
> 
> Catch the error from xfs_buf_get_noaddr(), and allow other memory
> allocations to fail and catch those errors too. Report the error
> to the console and fail the mount with ENOMEM.
> 
> Tested by manually injecting errors into xfs_buf_get_noaddr() and
> xlog_alloc_log().
> 
> Signed-off-by: Dave Chinner <david@fromorbit.com>
> ---
>  fs/xfs/xfs_log.c |   38 ++++++++++++++++++++++++++++++++++++--
>  1 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index 5184017..1dfa5fe 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c

> -	log = (xlog_t *)kmem_zalloc(sizeof(xlog_t), KM_SLEEP);
> +	log = (xlog_t *)kmem_zalloc(sizeof(xlog_t), KM_MAYFAIL);

You might want to remove the cast when you touch that line anyway.

>  	for (i=0; i < log->l_iclog_bufs; i++) {
>  		*iclogp = (xlog_in_core_t *)
> -			  kmem_zalloc(sizeof(xlog_in_core_t), KM_SLEEP);
> +			  kmem_zalloc(sizeof(xlog_in_core_t), KM_MAYFAIL);

Same here.


Modulo those nitpicks this looks good.