bcachefs: Fix reflink trigger

The trigger for reflink pointers wasn't always incrementing/decrementing
the refcounts correctly - this patch fixes that logic.

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

diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index a83d5de87d39108e579c1af72aeaf0771097e85a..8806e8306e4ef504c46f8bc68dcb64954e1d38dc 100644 (file)
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -1710,9 +1710,28 @@ static __le64 *bkey_refcount(struct bkey_i *k)
        }
 }
 
+static bool reflink_p_frag_references(struct bkey_s_c_reflink_p p,
+                                     u64 start, u64 end,
+                                     struct bkey_s_c k)
+{
+       if (start == end)
+               return false;
+
+       start   += le64_to_cpu(p.v->idx);
+       end     += le64_to_cpu(p.v->idx);
+
+       if (end <= bkey_start_offset(k.k))
+               return false;
+       if (start >= k.k->p.offset)
+               return false;
+       return true;
+}
+
 static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
                        struct bkey_s_c_reflink_p p,
                        u64 idx, unsigned sectors,
+                       unsigned front_frag,
+                       unsigned back_frag,
                        unsigned flags)
 {
        struct bch_fs *c = trans->c;
@@ -1720,6 +1739,7 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
        struct bkey_s_c k;
        struct bkey_i *n;
        __le64 *refcount;
+       int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
        s64 ret;
 
        ret = trans_get_key(trans, BTREE_ID_reflink,
@@ -1727,12 +1747,17 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
        if (ret < 0)
                return ret;
 
-       if ((flags & BTREE_TRIGGER_OVERWRITE) &&
-           (bkey_start_offset(k.k) < idx ||
-            k.k->p.offset > idx + sectors))
+       if (reflink_p_frag_references(p, 0, front_frag, k) &&
+           reflink_p_frag_references(p, back_frag, p.k->size, k)) {
+               BUG_ON(!(flags & BTREE_TRIGGER_OVERWRITE_SPLIT));
+               add = -add;
+       } else if (reflink_p_frag_references(p, 0, front_frag, k) ||
+                  reflink_p_frag_references(p, back_frag, p.k->size, k)) {
+               BUG_ON(!(flags & BTREE_TRIGGER_OVERWRITE));
                goto out;
+       }
 
-       sectors = k.k->p.offset - idx;
+       sectors = min_t(u64, sectors, k.k->p.offset - idx);
 
        n = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
        ret = PTR_ERR_OR_ZERO(n);
@@ -1751,7 +1776,8 @@ static int __bch2_trans_mark_reflink_p(struct btree_trans *trans,
                goto err;
        }
 
-       le64_add_cpu(refcount, !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1);
+       BUG_ON(!*refcount && (flags & BTREE_TRIGGER_OVERWRITE));
+       le64_add_cpu(refcount, add);
 
        if (!*refcount) {
                n->k.type = KEY_TYPE_deleted;
@@ -1772,13 +1798,18 @@ static int bch2_trans_mark_reflink_p(struct btree_trans *trans,
                        s64 sectors, unsigned flags)
 {
        u64 idx = le64_to_cpu(p.v->idx) + offset;
+       unsigned front_frag, back_frag;
        s64 ret = 0;
 
        sectors = abs(sectors);
        BUG_ON(offset + sectors > p.k->size);
 
+       front_frag = offset;
+       back_frag = offset + sectors;
+
        while (sectors) {
-               ret = __bch2_trans_mark_reflink_p(trans, p, idx, sectors, flags);
+               ret = __bch2_trans_mark_reflink_p(trans, p, idx, sectors,
+                                       front_frag, back_frag, flags);
                if (ret < 0)
                        break;
 

diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index 1e0effcece7f75da1f907dcb806378c298e2fadd..2b2e118114bd17f76297dc59688621700d8917db 100644 (file)
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -1959,7 +1959,10 @@ int __bch2_read_indirect_extent(struct btree_trans *trans,
        if (k.k->type != KEY_TYPE_reflink_v &&
            k.k->type != KEY_TYPE_indirect_inline_data) {
                bch_err_inum_ratelimited(trans->c, orig_k->k->k.p.inode,
-                               "pointer to nonexistent indirect extent");
+                       "%llu len %u points to nonexistent indirect extent %llu",
+                       orig_k->k->k.p.offset,
+                       orig_k->k->k.size,
+                       reflink_offset);
                bch2_inconsistent_error(trans->c);
                ret = -EIO;
                goto err;