bcachefs: Add otime, parent to bch_subvolume

Add two new fields to bch_subvolume:
 - otime: creation time
 - parent: For snapshots, this is the id of the subvolume the snapshot
   was created from

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

diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
index e9ac3aa6d91caeec061cfda04ded404b111fb1b9..ad87cdff854437fbb103158fce57b8fee1b34c1d 100644 (file)
--- a/fs/bcachefs/bcachefs_format.h
+++ b/fs/bcachefs/bcachefs_format.h
@@ -254,6 +254,11 @@ struct bkey_packed {
        __u8            pad[sizeof(struct bkey) - 3];
 } __packed __aligned(8);
 
+typedef struct {
+       __le64                  lo;
+       __le64                  hi;
+} bch_le128;
+
 #define BKEY_U64s                      (sizeof(struct bkey) / sizeof(__u64))
 #define BKEY_U64s_MAX                  U8_MAX
 #define BKEY_VAL_U64s_MAX              (BKEY_U64s_MAX - BKEY_U64s)
@@ -1106,6 +1111,9 @@ struct bch_subvolume {
        __le32                  flags;
        __le32                  snapshot;
        __le64                  inode;
+       __le32                  parent;
+       __le32                  pad;
+       bch_le128               otime;
 };
 
 LE32_BITMASK(BCH_SUBVOLUME_RO,         struct bch_subvolume, flags,  0,  1)

diff --git a/fs/bcachefs/subvolume.c b/fs/bcachefs/subvolume.c
index b14da196e7fd8d382992e15c698a01d11560d633..922360dec62779964a9be0e6d851146b11f0d06a 100644 (file)
--- a/fs/bcachefs/subvolume.c
+++ b/fs/bcachefs/subvolume.c
@@ -8,6 +8,8 @@
 #include "fs.h"
 #include "subvolume.h"
 
+static int bch2_subvolume_delete(struct btree_trans *, u32);
+
 /* Snapshot tree: */
 
 void bch2_snapshot_tree_to_text(struct printbuf *out, struct bch_fs *c,
@@ -643,12 +645,13 @@ static int check_subvol(struct btree_trans *trans,
                return ret;
 
        if (BCH_SUBVOLUME_UNLINKED(subvol.v)) {
+               bch2_fs_lazy_rw(c);
+
                ret = bch2_subvolume_delete(trans, iter->pos.offset);
-               if (ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart))
+               if (ret)
                        bch_err(c, "error deleting subvolume %llu: %s",
                                iter->pos.offset, bch2_err_str(ret));
-               if (ret)
-                       return ret;
+               return ret ?: -BCH_ERR_transaction_restart_nested;
        }
 
        if (!BCH_SUBVOLUME_SNAP(subvol.v)) {
@@ -1166,8 +1169,11 @@ void bch2_subvolume_to_text(struct printbuf *out, struct bch_fs *c,
        struct bkey_s_c_subvolume s = bkey_s_c_to_subvolume(k);
 
        prt_printf(out, "root %llu snapshot id %u",
-              le64_to_cpu(s.v->inode),
-              le32_to_cpu(s.v->snapshot));
+                  le64_to_cpu(s.v->inode),
+                  le32_to_cpu(s.v->snapshot));
+
+       if (bkey_val_bytes(s.k) > offsetof(struct bch_subvolume, parent))
+               prt_printf(out, " parent %u", le32_to_cpu(s.v->parent));
 }
 
 static __always_inline int
@@ -1204,23 +1210,71 @@ int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,
 int bch2_subvolume_get_snapshot(struct btree_trans *trans, u32 subvol,
                                u32 *snapid)
 {
-       struct bch_subvolume s;
+       struct btree_iter iter;
+       struct bkey_s_c k;
        int ret;
 
-       ret = bch2_subvolume_get_inlined(trans, subvol, true,
-                                        BTREE_ITER_CACHED|
-                                        BTREE_ITER_WITH_UPDATES,
-                                        &s);
-       if (!ret)
-               *snapid = le32_to_cpu(s.snapshot);
+       k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_subvolumes, POS(0, subvol),
+                              BTREE_ITER_CACHED|
+                              BTREE_ITER_WITH_UPDATES);
+       ret = bkey_err(k) ?: k.k->type == KEY_TYPE_subvolume ? 0 : -ENOENT;
+
+       if (likely(!ret))
+               *snapid = le32_to_cpu(bkey_s_c_to_subvolume(k).v->snapshot);
+       else if (bch2_err_matches(ret, ENOENT))
+               bch2_fs_inconsistent(trans->c, "missing subvolume %u", subvol);
+       bch2_trans_iter_exit(trans, &iter);
        return ret;
 }
 
+static int bch2_subvolume_reparent(struct btree_trans *trans,
+                                  struct btree_iter *iter,
+                                  struct bkey_s_c k,
+                                  u32 old_parent, u32 new_parent)
+{
+       struct bkey_i_subvolume *s;
+       int ret;
+
+       if (k.k->type != KEY_TYPE_subvolume)
+               return 0;
+
+       if (bkey_val_bytes(k.k) > offsetof(struct bch_subvolume, parent) &&
+           le32_to_cpu(bkey_s_c_to_subvolume(k).v->parent) != old_parent)
+               return 0;
+
+       s = bch2_bkey_make_mut_typed(trans, iter, k, 0, subvolume);
+       ret = PTR_ERR_OR_ZERO(s);
+       if (ret)
+               return ret;
+
+       s->v.parent = cpu_to_le32(new_parent);
+       return 0;
+}
+
+/*
+ * Scan for subvolumes with parent @subvolid_to_delete, reparent:
+ */
+static int bch2_subvolumes_reparent(struct btree_trans *trans, u32 subvolid_to_delete)
+{
+       struct btree_iter iter;
+       struct bkey_s_c k;
+       struct bch_subvolume s;
+
+       return lockrestart_do(trans,
+                       bch2_subvolume_get(trans, subvolid_to_delete, true,
+                                  BTREE_ITER_CACHED, &s)) ?:
+               for_each_btree_key_commit(trans, iter,
+                               BTREE_ID_subvolumes, POS_MIN, BTREE_ITER_PREFETCH, k,
+                               NULL, NULL, BTREE_INSERT_NOFAIL,
+                       bch2_subvolume_reparent(trans, &iter, k,
+                                       subvolid_to_delete, le32_to_cpu(s.parent)));
+}
+
 /*
  * Delete subvolume, mark snapshot ID as deleted, queue up snapshot
  * deletion/cleanup:
  */
-int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
+static int __bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
 {
        struct btree_iter iter;
        struct bkey_s_c_subvolume subvol;
@@ -1260,6 +1314,13 @@ err:
        return ret;
 }
 
+static int bch2_subvolume_delete(struct btree_trans *trans, u32 subvolid)
+{
+       return bch2_subvolumes_reparent(trans, subvolid) ?:
+               commit_do(trans, NULL, NULL, BTREE_INSERT_NOFAIL,
+                         __bch2_subvolume_delete(trans, subvolid));
+}
+
 void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *work)
 {
        struct bch_fs *c = container_of(work, struct bch_fs,
@@ -1280,8 +1341,7 @@ void bch2_subvolume_wait_for_pagecache_and_delete(struct work_struct *work)
                bch2_evict_subvolume_inodes(c, &s);
 
                for (id = s.data; id < s.data + s.nr; id++) {
-                       ret = bch2_trans_do(c, NULL, NULL, BTREE_INSERT_NOFAIL,
-                                     bch2_subvolume_delete(&trans, *id));
+                       ret = bch2_trans_run(c, bch2_subvolume_delete(&trans, *id));
                        if (ret) {
                                bch_err(c, "error deleting subvolume %u: %s", *id, bch2_err_str(ret));
                                break;
@@ -1359,6 +1419,7 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
                          u32 *new_snapshotid,
                          bool ro)
 {
+       struct bch_fs *c = trans->c;
        struct btree_iter dst_iter, src_iter = (struct btree_iter) { NULL };
        struct bkey_i_subvolume *new_subvol = NULL;
        struct bkey_i_subvolume *src_subvol = NULL;
@@ -1383,7 +1444,7 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
                                BTREE_ITER_CACHED, subvolume);
                ret = PTR_ERR_OR_ZERO(src_subvol);
                if (unlikely(ret)) {
-                       bch2_fs_inconsistent_on(ret == -ENOENT, trans->c,
+                       bch2_fs_inconsistent_on(ret == -ENOENT, c,
                                                "subvolume %u not found", src_subvolid);
                        goto err;
                }
@@ -1412,6 +1473,10 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
        new_subvol->v.flags     = 0;
        new_subvol->v.snapshot  = cpu_to_le32(new_nodes[0]);
        new_subvol->v.inode     = cpu_to_le64(inode);
+       new_subvol->v.parent    = cpu_to_le32(src_subvolid);
+       new_subvol->v.otime.lo  = cpu_to_le64(bch2_current_time(c));
+       new_subvol->v.otime.hi  = 0;
+
        SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
        SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 0);
 

diff --git a/fs/bcachefs/subvolume.h b/fs/bcachefs/subvolume.h
index dcd9f5f95535884a207187a949b418fccb4335dd..1ee4562198a61299cb35c7818b27d2022b564b51 100644 (file)
--- a/fs/bcachefs/subvolume.h
+++ b/fs/bcachefs/subvolume.h
@@ -156,7 +156,6 @@ int bch2_snapshot_node_create(struct btree_trans *, u32,
 int bch2_delete_dead_snapshots(struct bch_fs *);
 void bch2_delete_dead_snapshots_async(struct bch_fs *);
 
-int bch2_subvolume_delete(struct btree_trans *, u32);
 int bch2_subvolume_unlink(struct btree_trans *, u32);
 int bch2_subvolume_create(struct btree_trans *, u64, u32,
                          u32 *, u32 *, bool);