On Wed, Sep 27, 2017 at 02:34:10AM +0000, Darrick J. Wong wrote:
> Back in 88b8e1d6d7 ("Make xfs_metadump more robust against bad data"),
> metadump grew the ability to ignore a directory extent if it was longer
> than 20 blocks. Presumably this was to protect metadump from dumping
> absurdly long extents resulting from bmbt corruption, but it's certainly
> possible to create a directory with an extent longer than 20 blocks.
> Hilariously, the discards happen with no warning unless the caller
> explicitly set -w.
>
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
> This was raised to 1000 blocks in 7431d134fe8 ("Increase default maximum
> extent size for xfs_metadump when copying..."), but it's still possible
> to create a directory with an extent longer than 1000 blocks.
>
> Increase the threshold to MAXEXTLEN blocks because it's totally valid
> for the filesystem to create extents up to that length.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> v2: update manpage
> ---
> db/metadump.c | 2 +-
> man/man8/xfs_metadump.8 | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/db/metadump.c b/db/metadump.c
> index 6dd06c3..8ffb90f 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -32,7 +32,7 @@
> #include "field.h"
> #include "dir2.h"
>
> -#define DEFAULT_MAX_EXT_SIZE 1000
> +#define DEFAULT_MAX_EXT_SIZE MAXEXTLEN
>
> /*
> * It's possible that multiple files in a directory (or attributes
> diff --git a/man/man8/xfs_metadump.8 b/man/man8/xfs_metadump.8
> index 3731d6a..b6af4b6 100644
> --- a/man/man8/xfs_metadump.8
> +++ b/man/man8/xfs_metadump.8
> @@ -114,7 +114,7 @@ copied.
> .B \-m
> Set the maximum size of an allowed metadata extent. Extremely large metadata
> extents are likely to be corrupt, and will be skipped if they exceed
> -this value. The default size is 1000 blocks.
> +this value. The default size is 2097151 blocks.
> .TP
> .B \-o
> Disables obfuscation of file names and extended attributes.
> --
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--
Carlos
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