bcachefs: New check_nlinks algorithm for snapshots
With snapshots, using a radix tree for the table of link counts won't work anymore because we also need to distinguish between inodes with different snapshot IDs. Instead, this patch builds up a sorted array of inodes that have hardlinks that we can binary search on - taking advantage of the fact that with inode backpointers, the check_nlinks() pass _only_ needs to concern itself with inodes that have hardlinks now. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet
Kent Overstreet
parent
e3b4b48c17
commit
fc51b041b7
@ -12,8 +12,8 @@
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#include "super.h"
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#include "xattr.h"
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#include <linux/bsearch.h>
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#include <linux/dcache.h> /* struct qstr */
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#include <linux/generic-radix-tree.h>
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#define QSTR(n) { { { .len = strlen(n) } }, .name = n }
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@ -1132,38 +1132,120 @@ static int check_directory_structure(struct bch_fs *c)
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return bch2_trans_exit(&trans) ?: ret;
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}
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struct nlink {
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u32 count;
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struct nlink_table {
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size_t nr;
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size_t size;
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struct nlink {
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u64 inum;
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u32 snapshot;
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u32 count;
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} *d;
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};
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typedef GENRADIX(struct nlink) nlink_table;
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static void inc_link(struct bch_fs *c, nlink_table *links,
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u64 range_start, u64 *range_end, u64 inum)
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static int add_nlink(struct nlink_table *t, u64 inum, u32 snapshot)
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{
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struct nlink *link;
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if (t->nr == t->size) {
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size_t new_size = max_t(size_t, 128UL, t->size * 2);
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void *d = kvmalloc(new_size * sizeof(t->d[0]), GFP_KERNEL);
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if (!d) {
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return -ENOMEM;
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}
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if (inum < range_start || inum >= *range_end)
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return;
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memcpy(d, t->d, t->size * sizeof(t->d[0]));
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kvfree(t->d);
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if (inum - range_start >= SIZE_MAX / sizeof(struct nlink)) {
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*range_end = inum;
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return;
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t->d = d;
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t->size = new_size;
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}
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link = genradix_ptr_alloc(links, inum - range_start, GFP_KERNEL);
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if (!link) {
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bch_verbose(c, "allocation failed during fsck - will need another pass");
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*range_end = inum;
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return;
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}
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link->count++;
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t->d[t->nr++] = (struct nlink) {
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.inum = inum,
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.snapshot = snapshot,
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};
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return 0;
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}
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static int nlink_cmp(const void *_l, const void *_r)
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{
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const struct nlink *l = _l;
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const struct nlink *r = _r;
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return cmp_int(l->inum, r->inum) ?: cmp_int(l->snapshot, r->snapshot);
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}
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static void inc_link(struct bch_fs *c, struct nlink_table *links,
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u64 range_start, u64 range_end, u64 inum)
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{
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struct nlink *link, key = {
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.inum = inum, .snapshot = U32_MAX,
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};
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if (inum < range_start || inum >= range_end)
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return;
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link = __inline_bsearch(&key, links->d, links->nr,
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sizeof(links->d[0]), nlink_cmp);
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if (link)
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link->count++;
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}
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noinline_for_stack
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static int bch2_gc_walk_dirents(struct bch_fs *c, nlink_table *links,
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u64 range_start, u64 *range_end)
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static int check_nlinks_find_hardlinks(struct bch_fs *c,
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struct nlink_table *t,
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u64 start, u64 *end)
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{
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struct btree_trans trans;
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struct btree_iter *iter;
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struct bkey_s_c k;
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struct bkey_s_c_inode inode;
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struct bch_inode_unpacked u;
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int ret = 0;
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bch2_trans_init(&trans, c, BTREE_ITER_MAX, 0);
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for_each_btree_key(&trans, iter, BTREE_ID_inodes,
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POS(0, start), 0, k, ret) {
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if (k.k->type != KEY_TYPE_inode)
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continue;
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inode = bkey_s_c_to_inode(k);
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/*
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* Backpointer and directory structure checks are sufficient for
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* directories, since they can't have hardlinks:
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*/
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if (S_ISDIR(le16_to_cpu(inode.v->bi_mode)))
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continue;
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/* Should never fail, checked by bch2_inode_invalid: */
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BUG_ON(bch2_inode_unpack(inode, &u));
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if (!u.bi_nlink)
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continue;
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ret = add_nlink(t, k.k->p.offset, k.k->p.snapshot);
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if (ret) {
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*end = k.k->p.offset;
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ret = 0;
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break;
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}
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}
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bch2_trans_iter_put(&trans, iter);
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bch2_trans_exit(&trans);
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if (ret)
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bch_err(c, "error in fsck: btree error %i while walking inodes", ret);
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return ret;
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}
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noinline_for_stack
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static int check_nlinks_walk_dirents(struct bch_fs *c, struct nlink_table *links,
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u64 range_start, u64 range_end)
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{
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struct btree_trans trans;
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struct btree_iter *iter;
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@ -1195,80 +1277,58 @@ static int bch2_gc_walk_dirents(struct bch_fs *c, nlink_table *links,
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return ret;
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}
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static int check_inode_nlink(struct btree_trans *trans,
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struct btree_iter *iter,
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struct bkey_s_c_inode inode,
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unsigned nlink)
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{
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struct bch_fs *c = trans->c;
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struct bch_inode_unpacked u;
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int ret = 0;
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/*
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* Backpointer and directory structure checks are sufficient for
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* directories, since they can't have hardlinks:
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*/
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if (S_ISDIR(le16_to_cpu(inode.v->bi_mode)))
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return 0;
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if (!nlink) {
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bch_err(c, "no links found to inode %llu", inode.k->p.offset);
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return -EINVAL;
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}
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ret = bch2_inode_unpack(inode, &u);
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/* Should never happen, checked by bch2_inode_invalid: */
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if (bch2_fs_inconsistent_on(ret, c,
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"error unpacking inode %llu in fsck",
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inode.k->p.inode))
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return ret;
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if (fsck_err_on(bch2_inode_nlink_get(&u) != nlink, c,
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"inode %llu has wrong i_nlink (type %u i_nlink %u, should be %u)",
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u.bi_inum, mode_to_type(u.bi_mode),
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bch2_inode_nlink_get(&u), nlink)) {
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bch2_inode_nlink_set(&u, nlink);
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ret = __bch2_trans_do(trans, NULL, NULL,
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BTREE_INSERT_NOFAIL|
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BTREE_INSERT_LAZY_RW,
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bch2_inode_write(trans, iter, &u));
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if (ret)
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bch_err(c, "error in fsck: error %i updating inode", ret);
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}
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fsck_err:
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return ret;
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}
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noinline_for_stack
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static int bch2_gc_walk_inodes(struct bch_fs *c,
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nlink_table *links,
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static int check_nlinks_update_hardlinks(struct bch_fs *c,
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struct nlink_table *links,
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u64 range_start, u64 range_end)
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{
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struct btree_trans trans;
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struct btree_iter *iter;
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struct bkey_s_c k;
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struct nlink *link;
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struct bkey_s_c_inode inode;
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struct bch_inode_unpacked u;
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struct nlink *link = links->d;
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int ret = 0;
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bch2_trans_init(&trans, c, BTREE_ITER_MAX, 0);
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for_each_btree_key(&trans, iter, BTREE_ID_inodes,
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POS(0, range_start), 0, k, ret) {
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if (!k.k || k.k->p.offset >= range_end)
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if (k.k->p.offset >= range_end)
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break;
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if (k.k->type != KEY_TYPE_inode)
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continue;
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link = genradix_ptr(links, k.k->p.offset - range_start);
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ret = check_inode_nlink(&trans, iter,
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bkey_s_c_to_inode(k), link ? link->count : 0);
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if (ret)
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break;
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inode = bkey_s_c_to_inode(k);
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if (S_ISDIR(le16_to_cpu(inode.v->bi_mode)))
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continue;
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BUG_ON(bch2_inode_unpack(inode, &u));
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if (!u.bi_nlink)
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continue;
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while (link->inum < k.k->p.offset) {
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link++;
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BUG_ON(link >= links->d + links->nr);
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}
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if (fsck_err_on(bch2_inode_nlink_get(&u) != link->count, c,
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"inode %llu has wrong i_nlink (type %u i_nlink %u, should be %u)",
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u.bi_inum, mode_to_type(u.bi_mode),
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bch2_inode_nlink_get(&u), link->count)) {
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bch2_inode_nlink_set(&u, link->count);
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ret = __bch2_trans_do(&trans, NULL, NULL,
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BTREE_INSERT_NOFAIL|
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BTREE_INSERT_LAZY_RW,
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bch2_inode_write(&trans, iter, &u));
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if (ret)
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bch_err(c, "error in fsck: error %i updating inode", ret);
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}
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}
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fsck_err:
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bch2_trans_iter_put(&trans, iter);
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bch2_trans_exit(&trans);
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@ -1281,34 +1341,36 @@ static int bch2_gc_walk_inodes(struct bch_fs *c,
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noinline_for_stack
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static int check_nlinks(struct bch_fs *c)
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{
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nlink_table links;
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struct nlink_table links = { 0 };
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u64 this_iter_range_start, next_iter_range_start = 0;
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int ret = 0;
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bch_verbose(c, "checking inode nlinks");
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genradix_init(&links);
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do {
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this_iter_range_start = next_iter_range_start;
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next_iter_range_start = U64_MAX;
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ret = bch2_gc_walk_dirents(c, &links,
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ret = check_nlinks_find_hardlinks(c, &links,
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this_iter_range_start,
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&next_iter_range_start);
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ret = check_nlinks_walk_dirents(c, &links,
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this_iter_range_start,
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&next_iter_range_start);
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next_iter_range_start);
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if (ret)
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break;
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ret = bch2_gc_walk_inodes(c, &links,
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ret = check_nlinks_update_hardlinks(c, &links,
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this_iter_range_start,
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next_iter_range_start);
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if (ret)
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break;
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genradix_free(&links);
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links.nr = 0;
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} while (next_iter_range_start != U64_MAX);
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genradix_free(&links);
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kvfree(links.d);
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return ret;
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}
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