bcachefs: Improve reflink repair code

When a reflink pointer points to an indirect extent that doesn't exist,
we need to replace it with a KEY_TYPE_error key.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index dbf44704d0fc3e9fa696421ec9eb4c6bf926bd0d..ea3f7339ba585569888be886f2bd826b790ae1ff 100644 (file)
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -738,7 +738,7 @@ static int bch2_gc_mark_key(struct bch_fs *c, enum btree_id btree_id,
                *max_stale = max(*max_stale, ptr_stale(ca, ptr));
        }
 
-       bch2_mark_key(c, *k, flags);
+       ret = bch2_mark_key(c, *k, flags);
 fsck_err:
 err:
        if (ret)

diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index 2d2bdfb7977db31d734468ae4092d4050758de21..9c5d18b4efaa78ff8b4baf907e0823e476f5ac49 100644 (file)
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -14,6 +14,7 @@
 #include "ec.h"
 #include "error.h"
 #include "movinggc.h"
+#include "recovery.h"
 #include "reflink.h"
 #include "replicas.h"
 #include "subvolume.h"
@@ -1115,10 +1116,9 @@ static s64 __bch2_mark_reflink_p(struct bch_fs *c, struct bkey_s_c_reflink_p p,
 {
        struct reflink_gc *r;
        int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
+       s64 ret = 0;
 
-       while (1) {
-               if (*r_idx >= c->reflink_gc_nr)
-                       goto not_found;
+       while (*r_idx < c->reflink_gc_nr) {
                r = genradix_ptr(&c->reflink_gc_table, *r_idx);
                BUG_ON(!r);
 
@@ -1127,16 +1127,49 @@ static s64 __bch2_mark_reflink_p(struct bch_fs *c, struct bkey_s_c_reflink_p p,
                (*r_idx)++;
        }
 
+       if (*r_idx >= c->reflink_gc_nr ||
+           idx < r->offset - r->size) {
+               ret = p.k->size;
+               goto not_found;
+       }
+
        BUG_ON((s64) r->refcount + add < 0);
 
        r->refcount += add;
        return r->offset - idx;
 not_found:
-       bch2_fs_inconsistent(c,
-               "%llu:%llu len %u points to nonexistent indirect extent %llu",
-               p.k->p.inode, p.k->p.offset, p.k->size, idx);
-       bch2_inconsistent_error(c);
-       return -EIO;
+       if ((flags & BTREE_TRIGGER_GC) &&
+           (flags & BTREE_TRIGGER_NOATOMIC)) {
+               /*
+                * XXX: we're replacing the entire reflink pointer with an error
+                * key, we should just be replacing the part that was missing:
+                */
+               if (fsck_err(c, "%llu:%llu len %u points to nonexistent indirect extent %llu",
+                            p.k->p.inode, p.k->p.offset, p.k->size, idx)) {
+                       struct bkey_i_error *new;
+
+                       new = kmalloc(sizeof(*new), GFP_KERNEL);
+                       if (!new) {
+                               bch_err(c, "%s: error allocating new key", __func__);
+                               return -ENOMEM;
+                       }
+
+                       bkey_init(&new->k);
+                       new->k.type     = KEY_TYPE_error;
+                       new->k.p        = p.k->p;
+                       new->k.size     = p.k->size;
+                       ret = bch2_journal_key_insert(c, BTREE_ID_extents, 0, &new->k_i);
+
+               }
+       } else {
+               bch2_fs_inconsistent(c,
+                                    "%llu:%llu len %u points to nonexistent indirect extent %llu",
+                                    p.k->p.inode, p.k->p.offset, p.k->size, idx);
+               bch2_inconsistent_error(c);
+               ret = -EIO;
+       }
+fsck_err:
+       return ret;
 }
 
 static int bch2_mark_reflink_p(struct bch_fs *c,
@@ -1168,7 +1201,7 @@ static int bch2_mark_reflink_p(struct bch_fs *c,
 
        while (sectors) {
                ret = __bch2_mark_reflink_p(c, p, idx, flags, &l);
-               if (ret < 0)
+               if (ret <= 0)
                        return ret;
 
                ret = min_t(s64, ret, sectors);