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| author | Kent Overstreet <kent.overstreet@linux.dev> | 2025-04-02 14:31:12 -0400 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2025-04-03 12:11:43 -0400 |
| commit | 83d539b1b04705f972b53b4669fb587c54def0db (patch) | |
| tree | 83f094b56b01848cedb0114cfe5ed0619357fed1 /fs | |
| parent | 570f5050bb0739f24aeb94034d8ec134c450b4aa (diff) | |
bcachefs: Fix check_snapshot_exists() restart handling
Codepaths that create entries in the snapshots btree currently call
bch2_mark_snapshot(), which updates the in-memory snapshot table, before
transaction commit.
This is because bch2_mark_snapshot() is an atomic trigger, run with
btree write locks held, and isn't allowed to fail - but it might need to
reallocate the table, hence we call it early when we're still allowed to
fail.
This is generally harmless - if we fail, we'll have left an entry in the
snapshots table around, but nothing will reference it and it'll get
overwritten if reused by another transaction.
But check_snapshot_exists(), which reconstructs snapshots when the
snapshots btree has been corrupted or lost, was erronously rechecking if
the snapshot exists inside the transaction commit loop - so on
transaction restart (in this case mem_realloced), the second iteration
would return without repairing.
This code needs some cleanup: splitting out a "maybe realloc snapshots
table" helper would have avoided this, that will be in the next patch.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/bcachefs/snapshot.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c index c8536eb36060..b7de29aed839 100644 --- a/fs/bcachefs/snapshot.c +++ b/fs/bcachefs/snapshot.c @@ -843,9 +843,6 @@ static int check_snapshot_exists(struct btree_trans *trans, u32 id) { struct bch_fs *c = trans->c; - if (bch2_snapshot_exists(c, id)) - return 0; - /* Do we need to reconstruct the snapshot_tree entry as well? */ struct btree_iter iter; struct bkey_s_c k; |