xfs_scrub: automatic downgrades to dry-run mode in service mode

When service mode is enabled, xfs_scrub is being run within the context
of a systemd service.  The service description language doesn't have any
particularly good constructs for adding in a '-n' argument if the
filesystem is readonly, which means that xfs_scrub is passed a path, and
needs to switch to dry-run mode on its own if the fs is mounted
readonly or the kernel doesn't support repairs.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/scrub/phase1.c b/scrub/phase1.c
index 516d929d6268b887ad2dd2c5691914d3551ebaaf..095c045915a706e4ad808409badb26d1ff2ad7c4 100644 (file)
--- a/scrub/phase1.c
+++ b/scrub/phase1.c
@@ -216,6 +216,19 @@ _("Kernel metadata scrubbing facility is not available."));
                return ECANCELED;
        }
 
+       /*
+        * Normally, callers are required to pass -n if the provided path is a
+        * readonly filesystem or the kernel wasn't built with online repair
+        * enabled.  However, systemd services are not scripts and cannot
+        * determine either of these conditions programmatically.  Change the
+        * behavior to dry-run mode if either condition is detected.
+        */
+       if (repair_want_service_downgrade(ctx)) {
+               str_info(ctx, ctx->mntpoint,
+_("Filesystem cannot be repaired in service mode, downgrading to dry-run mode."));
+               ctx->mode = SCRUB_MODE_DRY_RUN;
+       }
+
        /* Do we need kernel-assisted metadata repair? */
        if (ctx->mode != SCRUB_MODE_DRY_RUN && !can_repair(ctx)) {
                str_error(ctx, ctx->mntpoint,

diff --git a/scrub/repair.c b/scrub/repair.c
index 19f5c9052affb21e24fe235b34f9247772b295ce..2883f98af4ab94b360de167ecf3bdfc9795459a5 100644 (file)
--- a/scrub/repair.c
+++ b/scrub/repair.c
@@ -45,6 +45,39 @@ static const unsigned int repair_deps[XFS_SCRUB_TYPE_NR] = {
 };
 #undef DEP
 
+/*
+ * Decide if we want an automatic downgrade to dry-run mode.  This is only
+ * for service mode, where we are fed a path and have to figure out if the fs
+ * is repairable or not.
+ */
+bool
+repair_want_service_downgrade(
+       struct scrub_ctx                *ctx)
+{
+       struct xfs_scrub_metadata       meta = {
+               .sm_type                = XFS_SCRUB_TYPE_PROBE,
+               .sm_flags               = XFS_SCRUB_IFLAG_REPAIR,
+       };
+       int                             error;
+
+       if (ctx->mode == SCRUB_MODE_DRY_RUN)
+               return false;
+       if (!is_service)
+               return false;
+       if (debug_tweak_on("XFS_SCRUB_NO_KERNEL"))
+               return false;
+
+       error = -xfrog_scrub_metadata(&ctx->mnt, &meta);
+       switch (error) {
+       case EROFS:
+       case ENOTRECOVERABLE:
+       case EOPNOTSUPP:
+               return true;
+       }
+
+       return false;
+}
+
 /* Repair some metadata. */
 static int
 xfs_repair_metadata(

diff --git a/scrub/repair.h b/scrub/repair.h
index a685e90374cb7b41e2b77359c11edb32abf0b4cc..411a379f6faae6f2675479093af9fe8e1fb366cf 100644 (file)
--- a/scrub/repair.h
+++ b/scrub/repair.h
@@ -102,4 +102,6 @@ repair_item_completely(
        return repair_item(ctx, sri, XRM_FINAL_WARNING | XRM_NOPROGRESS);
 }
 
+bool repair_want_service_downgrade(struct scrub_ctx *ctx);
+
 #endif /* XFS_SCRUB_REPAIR_H_ */