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bcachefs: Fix check_path() for snapshots

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check_path() wasn't checking the snapshot ID when checking for directory
structure loops - so, snapshots would cause us to detect a loop that
wasn't actually a loop.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet 2021-10-20 17:59:38 -04:00 committed by Kent Overstreet
parent 6d76aefea1
commit 6e0c886d3c
1 changed files with 45 additions and 19 deletions
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64
fs/bcachefs/fsck.c
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@ -1357,10 +1357,10 @@ static int check_dirent_target(struct btree_trans *trans,
}
if (fsck_err_on(!backpointer_exists, c,
"inode %llu has wrong backpointer:\n"
"inode %llu:%u has wrong backpointer:\n"
"got %llu:%llu\n"
"should be %llu:%llu",
target->bi_inum,
target->bi_inum, target_snapshot,
target->bi_dir,
target->bi_dir_offset,
d.k->p.inode,
@ -1730,10 +1730,23 @@ struct pathbuf {
struct pathbuf_entry {
u64 inum;
u32 snapshot;
} *entries;
};
static int path_down(struct pathbuf *p, u64 inum)
static bool path_is_dup(struct pathbuf *p, u64 inum, u32 snapshot)
{
struct pathbuf_entry *i;
for (i = p->entries; i < p->entries + p->nr; i++)
if (i->inum == inum &&
i->snapshot == snapshot)
return true;
return false;
}
static int path_down(struct pathbuf *p, u64 inum, u32 snapshot)
{
if (p->nr == p->size) {
size_t new_size = max_t(size_t, 256UL, p->size * 2);
@ -1749,18 +1762,23 @@ static int path_down(struct pathbuf *p, u64 inum)
};
p->entries[p->nr++] = (struct pathbuf_entry) {
.inum = inum,
.inum = inum,
.snapshot = snapshot,
};
return 0;
}
/*
* Check that a given inode is reachable from the root:
*
* XXX: we should also be verifying that inodes are in the right subvolumes
*/
static int check_path(struct btree_trans *trans,
struct pathbuf *p,
struct bch_inode_unpacked *inode,
u32 snapshot)
{
struct bch_fs *c = trans->c;
size_t i;
int ret = 0;
snapshot = snapshot_t(c, snapshot)->equiv;
@ -1768,17 +1786,19 @@ static int check_path(struct btree_trans *trans,
while (!(inode->bi_inum == BCACHEFS_ROOT_INO &&
inode->bi_subvol == BCACHEFS_ROOT_SUBVOL)) {
u32 parent_snapshot = snapshot;
if (inode->bi_parent_subvol) {
u64 inum;
ret = subvol_lookup(trans, inode->bi_parent_subvol,
&snapshot, &inum);
&parent_snapshot, &inum);
if (ret)
break;
}
ret = lockrestart_do(trans,
inode_backpointer_exists(trans, inode, snapshot));
inode_backpointer_exists(trans, inode, parent_snapshot));
if (ret < 0)
break;
@ -1797,17 +1817,31 @@ static int check_path(struct btree_trans *trans,
if (!S_ISDIR(inode->bi_mode))
break;
ret = path_down(p, inode->bi_inum);
ret = path_down(p, inode->bi_inum, snapshot);
if (ret) {
bch_err(c, "memory allocation failure");
return ret;
}
for (i = 0; i < p->nr; i++) {
if (inode->bi_dir != p->entries[i].inum)
continue;
snapshot = parent_snapshot;
ret = lookup_inode(trans, inode->bi_dir, inode, &snapshot);
if (ret) {
/* Should have been caught in dirents pass */
bch_err(c, "error looking up parent directory: %i", ret);
break;
}
if (path_is_dup(p, inode->bi_inum, snapshot)) {
struct pathbuf_entry *i;
/* XXX print path */
bch_err(c, "directory structure loop");
for (i = p->entries; i < p->entries + p->nr; i++)
pr_err("%llu:%u", i->inum, i->snapshot);
pr_err("%llu:%u", inode->bi_inum, snapshot);
if (!fsck_err(c, "directory structure loop"))
return 0;
@ -1819,14 +1853,6 @@ static int check_path(struct btree_trans *trans,
}
ret = reattach_inode(trans, inode, snapshot);
break;
}
ret = lookup_inode(trans, inode->bi_dir, inode, &snapshot);
if (ret) {
/* Should have been caught in dirents pass */
bch_err(c, "error looking up parent directory: %i", ret);
break;
}
}
fsck_err: