On Feb 13, 2020, at 3:15 AM, Jan Kara <jack@xxxxxxx> wrote:
>
> When directory link count is set to overflow value (1) but during pass 4
> we find out the exact link count would fit, we either silently fix this
> (which is not great because e2fsck then reports the fs was modified but
> output doesn't indicate why in any way), or we report that link count is
> wrong and ask whether we should fix it (in case -n option was
> specified). The second case is even more misleading because it suggests
> non-trivial fs corruption which then gets silently fixed on the next
> run. Similarly to how we fix up other non-problems, just create a new
> error message for the case directory link count is not overflown anymore
> and always report it to clarify what is going on.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
> ---
> e2fsck/pass4.c | 20 ++++++++++++++++----
> e2fsck/problem.c | 5 +++++
> e2fsck/problem.h | 3 +++
> 3 files changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/e2fsck/pass4.c b/e2fsck/pass4.c
> index 10be7f87180d..8c2d2f1fca12 100644
> --- a/e2fsck/pass4.c
> +++ b/e2fsck/pass4.c
> @@ -237,6 +237,8 @@ void e2fsck_pass4(e2fsck_t ctx)
> link_counted = 1;
> }
> if (link_counted != link_count) {
> + int fix_nlink = 0;
> +
> e2fsck_read_inode_full(ctx, i, EXT2_INODE(inode),
> inode_size, "pass4");
> pctx.ino = i;
> @@ -250,10 +252,20 @@ void e2fsck_pass4(e2fsck_t ctx)
> pctx.num = link_counted;
> /* i_link_count was previously exceeded, but no longer
> * is, fix this but don't consider it an error */
> - if ((isdir && link_counted > 1 &&
> - (inode->i_flags & EXT2_INDEX_FL) &&
> - link_count == 1 && !(ctx->options & E2F_OPT_NO)) ||
> - fix_problem(ctx, PR_4_BAD_REF_COUNT, &pctx)) {
> + if (isdir && link_counted > 1 &&
> + (inode->i_flags & EXT2_INDEX_FL) &&
> + link_count == 1) {
> + if ((ctx->options & E2F_OPT_READONLY) == 0) {
> + fix_nlink =
> + fix_problem(ctx,
> + PR_4_DIR_OVERFLOW_REF_COUNT,
> + &pctx);
> + }
> + } else {
> + fix_nlink = fix_problem(ctx, PR_4_BAD_REF_COUNT,
> + &pctx);
> + }
> + if (fix_nlink) {
> inode->i_links_count = link_counted;
> e2fsck_write_inode_full(ctx, i,
> EXT2_INODE(inode),
> diff --git a/e2fsck/problem.c b/e2fsck/problem.c
> index c7c0ba986006..e79c853b2096 100644
> --- a/e2fsck/problem.c
> +++ b/e2fsck/problem.c
> @@ -2035,6 +2035,11 @@ static struct e2fsck_problem problem_table[] = {
> N_("@d exceeds max links, but no DIR_NLINK feature in @S.\n"),
> PROMPT_FIX, 0, 0, 0, 0 },
>
> + /* Directory inode ref count set to overflow but could be exact value */
> + { PR_4_DIR_OVERFLOW_REF_COUNT,
> + N_("@d @i %i ref count set to overflow but could be exact value %N. "),
> + PROMPT_FIX, PR_PREEN_OK, 0, 0, 0 },
> +
> /* Pass 5 errors */
>
> /* Pass 5: Checking group summary information */
> diff --git a/e2fsck/problem.h b/e2fsck/problem.h
> index c7f65f6dee0f..4185e5175cab 100644
> --- a/e2fsck/problem.h
> +++ b/e2fsck/problem.h
> @@ -1164,6 +1164,9 @@ struct problem_context {
> /* directory exceeds max links, but no DIR_NLINK feature in superblock */
> #define PR_4_DIR_NLINK_FEATURE 0x040006
>
> +/* Directory ref count set to overflow but it doesn't have to be */
> +#define PR_4_DIR_OVERFLOW_REF_COUNT 0x040007
> +
> /*
> * Pass 5 errors
> */
> --
> 2.16.4
>
Cheers, Andreas
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