[PATCH] Proposal for more detail in scrub doc

[PATCH] Proposal for more detail in scrub doc

[Andrea Gelmini]

Wise words from Qu:
https://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg82557.html
---
 Documentation/btrfs-scrub.asciidoc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/btrfs-scrub.asciidoc b/Documentation/btrfs-scrub.asciidoc
index 4c49269..1fc085c 100644
--- a/Documentation/btrfs-scrub.asciidoc
+++ b/Documentation/btrfs-scrub.asciidoc
@@ -16,7 +16,8 @@ and metadata blocks from all devices and verify checksums. Automatically repair
 corrupted blocks if there's a correct copy available.
 
 NOTE: Scrub is not a filesystem checker (fsck) and does not verify nor repair
-structural damage in the filesystem.
+structural damage in the filesystem. It only checks csum of data and tree blocks,
+it doesn't ensure the content of tree blocks are OK.
 
 The user is supposed to run it manually or via a periodic system service. The
 recommended period is a month but could be less. The estimated device bandwidth
-- 
2.20.0.rc1.28.g8a4ee09a8a

Re: [PATCH] Proposal for more detail in scrub doc

[Nikolay Borisov]

On 27.11.18 г. 16:14 ч., Andrea Gelmini wrote:
> Wise words from Qu:
> https://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg82557.html
> ---
>  Documentation/btrfs-scrub.asciidoc | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/btrfs-scrub.asciidoc b/Documentation/btrfs-scrub.asciidoc
> index 4c49269..1fc085c 100644
> --- a/Documentation/btrfs-scrub.asciidoc
> +++ b/Documentation/btrfs-scrub.asciidoc
> @@ -16,7 +16,8 @@ and metadata blocks from all devices and verify checksums. Automatically repair
>  corrupted blocks if there's a correct copy available.
>  
>  NOTE: Scrub is not a filesystem checker (fsck) and does not verify nor repair
> -structural damage in the filesystem.
> +structural damage in the filesystem. It only checks csum of data and tree blocks,
> +it doesn't ensure the content of tree blocks are OK.

I would rephrase this as:

"It only ensures that the checksum of given data/metadata blocks match
but doesn't guarantee that the contents themselves are consistent"

It sounds a bit more formal which I think is more appropriate for a man
page.


>  
>  The user is supposed to run it manually or via a periodic system service. The
>  recommended period is a month but could be less. The estimated device bandwidth
> 

Re: [PATCH] Proposal for more detail in scrub doc

[David Sterba]

On Tue, Nov 27, 2018 at 03:14:37PM +0100, Andrea Gelmini wrote:
> Wise words from Qu:
> https://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg82557.html
> ---
>  Documentation/btrfs-scrub.asciidoc | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/btrfs-scrub.asciidoc b/Documentation/btrfs-scrub.asciidoc
> index 4c49269..1fc085c 100644
> --- a/Documentation/btrfs-scrub.asciidoc
> +++ b/Documentation/btrfs-scrub.asciidoc
> @@ -16,7 +16,8 @@ and metadata blocks from all devices and verify checksums. Automatically repair
>  corrupted blocks if there's a correct copy available.
>  
>  NOTE: Scrub is not a filesystem checker (fsck) and does not verify nor repair
> -structural damage in the filesystem.
> +structural damage in the filesystem. It only checks csum of data and tree blocks,
> +it doesn't ensure the content of tree blocks are OK.

Thanks for the suggestion, I've enhanced the note in the docs so it
fills in the details you've been missing.