From 741daa5be5c8d9cccaaac9759eb99893f1beb09b Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Tue, 21 Aug 2018 19:42:00 -0400
Subject: [PATCH] bcachefs: Dirent repair code
There was a bug for awhile in previous kernels where we weren't
computing dirent name lengths correctly and we weren't zeroing out
padding at the end of dirents (due to struct bch_dirent changing size by
adding __attribute__((aligned)), and not updating other code to use
offsetof).
This patch fixes dirents with junk at the end, by going off of the
dirent's hash.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/dirent.c | 14 +----
fs/bcachefs/dirent.h | 6 +++
fs/bcachefs/fsck.c | 123 +++++++++++++++++++++++++++++++++++++++++--
3 files changed, 126 insertions(+), 17 deletions(-)
diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index d5e174e1e59f4..0651f5575131a 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -16,16 +16,7 @@ unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
unsigned len = bkey_val_bytes(d.k) -
offsetof(struct bch_dirent, d_name);
- while (len && !d.v->d_name[len - 1])
- --len;
-
- return len;
-}
-
-static unsigned dirent_val_u64s(unsigned len)
-{
- return DIV_ROUND_UP(offsetof(struct bch_dirent, d_name) + len,
- sizeof(u64));
+ return strnlen(d.v->d_name, len);
}
static u64 bch2_dirent_hash(const struct bch_hash_info *info,
@@ -108,9 +99,6 @@ const char *bch2_dirent_invalid(const struct bch_fs *c, struct bkey_s_c k)
if (len > BCH_NAME_MAX)
return "dirent name too big";
- if (memchr(d.v->d_name, '/', len))
- return "dirent name has invalid characters";
-
return NULL;
case BCH_DIRENT_WHITEOUT:
return bkey_val_bytes(k.k) != 0
diff --git a/fs/bcachefs/dirent.h b/fs/bcachefs/dirent.h
index ac28f83d6b2da..30d2143d4ca7c 100644
--- a/fs/bcachefs/dirent.h
+++ b/fs/bcachefs/dirent.h
@@ -23,6 +23,12 @@ struct bch_inode_info;
unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent);
+static inline unsigned dirent_val_u64s(unsigned len)
+{
+ return DIV_ROUND_UP(offsetof(struct bch_dirent, d_name) + len,
+ sizeof(u64));
+}
+
int __bch2_dirent_create(struct btree_trans *, u64,
const struct bch_hash_info *, u8,
const struct qstr *, u64, int);
diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index 2430833dbce8a..1bdb31c5d5def 100644
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -248,6 +248,29 @@ fsck_err:
return ret;
}
+static bool key_has_correct_hash(const struct bch_hash_desc desc,
+ struct hash_check *h, struct bch_fs *c,
+ struct btree_iter *k_iter, struct bkey_s_c k)
+{
+ u64 hash;
+
+ if (k.k->type != desc.whiteout_type &&
+ k.k->type != desc.key_type)
+ return true;
+
+ if (k.k->p.offset != h->next)
+ bch2_btree_iter_copy(h->chain, k_iter);
+ h->next = k.k->p.offset + 1;
+
+ if (k.k->type != desc.key_type)
+ return true;
+
+ hash = desc.hash_bkey(&h->info, k);
+
+ return hash >= h->chain->pos.offset &&
+ hash <= k.k->p.offset;
+}
+
static int hash_check_key(const struct bch_hash_desc desc,
struct hash_check *h, struct bch_fs *c,
struct btree_iter *k_iter, struct bkey_s_c k)
@@ -271,9 +294,10 @@ static int hash_check_key(const struct bch_hash_desc desc,
if (fsck_err_on(hashed < h->chain->pos.offset ||
hashed > k.k->p.offset, c,
- "hash table key at wrong offset: %llu, "
+ "hash table key at wrong offset: btree %u, %llu, "
"hashed to %llu chain starts at %llu\n%s",
- k.k->p.offset, hashed, h->chain->pos.offset,
+ desc.btree_id, k.k->p.offset,
+ hashed, h->chain->pos.offset,
(bch2_bkey_val_to_text(c, bkey_type(0, desc.btree_id),
buf, sizeof(buf), k), buf))) {
ret = hash_redo_key(desc, h, c, k_iter, k, hashed);
@@ -289,6 +313,90 @@ fsck_err:
return ret;
}
+static int check_dirent_hash(struct hash_check *h, struct bch_fs *c,
+ struct btree_iter *iter, struct bkey_s_c *k)
+{
+ struct bkey_i_dirent *d = NULL;
+ int ret = -EINVAL;
+ char buf[200];
+ unsigned len;
+ u64 hash;
+
+ if (key_has_correct_hash(bch2_dirent_hash_desc, h, c, iter, *k))
+ return 0;
+
+ len = bch2_dirent_name_bytes(bkey_s_c_to_dirent(*k));
+ BUG_ON(!len);
+
+ memcpy(buf, bkey_s_c_to_dirent(*k).v->d_name, len);
+ buf[len] = '\0';
+
+ d = kmalloc(bkey_bytes(k->k), GFP_KERNEL);
+ if (!d) {
+ bch_err(c, "memory allocation failure");
+ return -ENOMEM;
+ }
+
+ bkey_reassemble(&d->k_i, *k);
+
+ do {
+ --len;
+ if (!len)
+ goto err_redo;
+
+ d->k.u64s = BKEY_U64s + dirent_val_u64s(len);
+
+ BUG_ON(bkey_val_bytes(&d->k) <
+ offsetof(struct bch_dirent, d_name) + len);
+
+ memset(d->v.d_name + len, 0,
+ bkey_val_bytes(&d->k) -
+ offsetof(struct bch_dirent, d_name) - len);
+
+ hash = bch2_dirent_hash_desc.hash_bkey(&h->info,
+ bkey_i_to_s_c(&d->k_i));
+ } while (hash < h->chain->pos.offset ||
+ hash > k->k->p.offset);
+
+ if (fsck_err(c, "dirent with junk at end, was %s (%zu) now %s (%u)",
+ buf, strlen(buf), d->v.d_name, len)) {
+ ret = bch2_btree_insert_at(c, NULL, NULL,
+ BTREE_INSERT_NOFAIL,
+ BTREE_INSERT_ENTRY(iter, &d->k_i));
+ if (ret)
+ goto err;
+
+ *k = bch2_btree_iter_peek(iter);
+
+ BUG_ON(k->k->type != BCH_DIRENT);
+ }
+err:
+fsck_err:
+ kfree(d);
+ return ret;
+err_redo:
+ bch_err(c, "cannot fix dirent by removing trailing garbage %s (%zu)",
+ buf, strlen(buf));
+
+ hash = bch2_dirent_hash_desc.hash_bkey(&h->info, *k);
+
+ if (fsck_err(c, "hash table key at wrong offset: btree %u, offset %llu, "
+ "hashed to %llu chain starts at %llu\n%s",
+ BTREE_ID_DIRENTS,
+ k->k->p.offset, hash, h->chain->pos.offset,
+ (bch2_bkey_val_to_text(c, bkey_type(0, BTREE_ID_DIRENTS),
+ buf, sizeof(buf), *k), buf))) {
+ ret = hash_redo_key(bch2_dirent_hash_desc,
+ h, c, iter, *k, hash);
+ if (ret)
+ bch_err(c, "hash_redo_key err %i", ret);
+ else
+ ret = 1;
+ }
+
+ goto err;
+}
+
static int bch2_inode_truncate(struct bch_fs *c, u64 inode_nr, u64 new_size)
{
return bch2_btree_delete_range(c, BTREE_ID_EXTENTS,
@@ -435,11 +543,13 @@ static int check_dirents(struct bch_fs *c)
if (w.first_this_inode && w.have_inode)
hash_check_set_inode(&h, c, &w.inode);
- ret = hash_check_key(bch2_dirent_hash_desc, &h, c, iter, k);
+ ret = check_dirent_hash(&h, c, iter, &k);
if (ret > 0) {
ret = 0;
continue;
}
+ if (ret)
+ goto fsck_err;
if (ret)
goto fsck_err;
@@ -458,7 +568,12 @@ static int check_dirents(struct bch_fs *c)
". dirent") ||
fsck_err_on(name_len == 2 &&
!memcmp(d.v->d_name, "..", 2), c,
- ".. dirent")) {
+ ".. dirent") ||
+ fsck_err_on(name_len == 2 &&
+ !memcmp(d.v->d_name, "..", 2), c,
+ ".. dirent") ||
+ fsck_err_on(memchr(d.v->d_name, '/', name_len), c,
+ "dirent name has invalid chars")) {
ret = remove_dirent(c, iter, d);
if (ret)
goto err;
--
2.30.2