Re: [PATCH 2/2] block: file-posix: Replace posix_fallocate with fallocate

[Alberto Garcia]

On Mon 31 Aug 2020 04:01:27 PM CEST, Nir Soffer wrote:
> If fallocate() is not supported, posix_fallocate() falls back to
> inefficient allocation, writing one byte for every 4k bytes[1]. This is
> very slow compared with writing zeros. In oVirt we measured ~400%
> improvement in allocation time when replacing posix_fallocate() with
> manually writing zeroes[2].
>
> We also know that posix_fallocated() does not work well when using OFD
> locks[3]. We don't know the reason yet for this issue yet.
>
> Change preallocate_falloc() to use fallocate() instead of
> posix_falloate(), and fall back to full preallocation if not
> supported.


>      case PREALLOC_MODE_FALLOC:
>          result = preallocate_falloc(fd, current_length, offset, errp);
> -        goto out;
> +        if (result != -ENOTSUP)
> +            goto out;
> +        /* If fallocate() is not supported, fallback to full preallocation. 
> */

With the missing braces in this if statement,

Reviewed-by: Alberto Garcia <berto@igalia.com>

Berto