Re: On current git head webservers stopped working

From: Gabriel C
Date: Fri Jul 13 2007 - 05:50:19 EST


Jens Axboe wrote:
> On Fri, Jul 13 2007, Gabriel C wrote:
>
>> Hello ,
>>
>> While doing some tests with 2.6.22-git2 ( at the time head
>> 4eb6bf6bfb580afaf1e1a1d30cba17a078530cf4 ) all my webservers stopped
>> working.
>> I can't get any file using wget or whatever else , everything hangs
>> after 1% forever.
>>
>> I bisected this and here the result:
>>
>> 534f2aaa6ab07cd71164180bc958a7dcde41db11 is first bad commit
>> commit 534f2aaa6ab07cd71164180bc958a7dcde41db11
>> Author: Jens Axboe <jens.axboe@xxxxxxxxxx>
>> Date: Fri Jun 1 14:52:37 2007 +0200
>>
>> sys_sendfile: switch to using ->splice_read, if available
>>
>> This patch makes sendfile prefer to use ->splice_read(), if it's
>> available in the file_operations structure.
>>
>> Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
>>
>> :040000 040000 b19013793692eee0f632b3703dca0bd40cea753f
>> ed50576c0d3f0d3ce9f1a2ac9336d1164b45f63f M fs
>>
>
> Does this work?
>

Yes , it does. Thx :)

> diff --git a/fs/splice.c b/fs/splice.c
> index ed2ce99..92646aa 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -491,7 +491,7 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
>
> ret = 0;
> spliced = 0;
> - while (len) {
> + while (len && !spliced) {
> ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
>
> if (ret < 0)
> @@ -1051,15 +1051,10 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
> sd->flags &= ~SPLICE_F_NONBLOCK;
>
> while (len) {
> - size_t read_len, max_read_len;
> -
> - /*
> - * Do at most PIPE_BUFFERS pages worth of transfer:
> - */
> - max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE));
> + size_t read_len;
>
> - ret = do_splice_to(in, &sd->pos, pipe, max_read_len, flags);
> - if (unlikely(ret < 0))
> + ret = do_splice_to(in, &sd->pos, pipe, len, flags);
> + if (unlikely(ret <= 0))
> goto out_release;
>
> read_len = ret;
> @@ -1071,26 +1066,17 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
> * could get stuck data in the internal pipe:
> */
> ret = actor(pipe, sd);
> - if (unlikely(ret < 0))
> + if (unlikely(ret <= 0))
> goto out_release;
>
> bytes += ret;
> len -= ret;
>
> - /*
> - * In nonblocking mode, if we got back a short read then
> - * that was due to either an IO error or due to the
> - * pagecache entry not being there. In the IO error case
> - * the _next_ splice attempt will produce a clean IO error
> - * return value (not a short read), so in both cases it's
> - * correct to break out of the loop here:
> - */
> - if ((flags & SPLICE_F_NONBLOCK) && (read_len < max_read_len))
> - break;
> + if (ret < read_len)
> + goto out_release;
> }
>
> pipe->nrbufs = pipe->curbuf = 0;
> -
> return bytes;
>
> out_release:
> @@ -1152,10 +1138,12 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
> .pos = *ppos,
> .u.file = out,
> };
> - size_t ret;
> + long ret;
>
> ret = splice_direct_to_actor(in, &sd, direct_splice_actor);
> - *ppos = sd.pos;
> + if (ret > 0)
> + *ppos += ret;
> +
> return ret;
> }
>
>
>

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