On May 30, 2018, at 6:51 AM, Jan Kara <jack@xxxxxxx> wrote:
>
> Add a flag to ext2fs_open() which allows to open a filesystem even if
> superblock is somewhat inconsistent. Use this flag from e2fsck as a last
> resort to try to fix the superblok.
>
> Currently, the flag does nothing. We'll relax checks in ext2fs_open()
> once e2fsck is able to handle corresponding corruption gracefully.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
I'd think this patch would go at the end once ext2fs_open() checks for
this flag and handles it, but either way...
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
> ---
> e2fsck/unix.c | 22 +++++++++++++++++++++-
> lib/ext2fs/ext2fs.h | 1 +
> 2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/e2fsck/unix.c b/e2fsck/unix.c
> index cbe5ec5034cb..55e21ea0aeac 100644
> --- a/e2fsck/unix.c
> +++ b/e2fsck/unix.c
> @@ -1364,7 +1364,7 @@ int main (int argc, char *argv[])
> const char *lib_ver_date;
> int my_ver, lib_ver;
> e2fsck_t ctx;
> - blk64_t orig_superblock;
> + blk64_t orig_superblock = ~(blk64_t)0;
> struct problem_context pctx;
> int flags, run_result, was_changed;
> int journal_size;
> @@ -1571,6 +1571,26 @@ failure:
> "check of the device.\n"));
> #endif
> else {
> + /*
> + * Let's try once more will less consistency checking
> + * so that we are able to recover from more errors
> + * (e.g. some tool messing up some value in the sb).
> + */
> + if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS)) {
> + if (fs)
> + ext2fs_close_free(&fs);
> + log_out(ctx, _("%s: Trying to load superblock "
> + "despite errors...\n"),
> + ctx->program_name);
> + flags |= EXT2_FLAG_IGNORE_SB_ERRORS;
> + /*
> + * If we tried backup sb, revert to the
> + * original one now.
> + */
> + if (orig_superblock != ~(blk64_t)0)
> + ctx->superblock = orig_superblock;
> + goto restart;
> + }
> fix_problem(ctx, PR_0_SB_CORRUPT, &pctx);
> if (retval == EXT2_ET_BAD_MAGIC)
> check_plausibility(ctx->filesystem_name,
> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> index 6774e32c91c2..250fd174cd48 100644
> --- a/lib/ext2fs/ext2fs.h
> +++ b/lib/ext2fs/ext2fs.h
> @@ -195,6 +195,7 @@ typedef struct ext2_file *ext2_file_t;
> #define EXT2_FLAG_DIRECT_IO 0x80000
> #define EXT2_FLAG_SKIP_MMP 0x100000
> #define EXT2_FLAG_IGNORE_CSUM_ERRORS 0x200000
> +#define EXT2_FLAG_IGNORE_SB_ERRORS 0x400000
>
> /*
> * Special flag in the ext2 inode i_flag field that means that this is
> --
> 2.13.6
>
Cheers, Andreas
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