bcachefs: Add subvolume to ei_inode_info

Filesystem operations generally operate within a subvolume: at the start
of every btree transaction we'll be looking up (and locking) the
subvolume to get the current snapshot ID, which we then use for our
other btree lookups in BTREE_ITER_FILTER_SNAPSHOTS mode.

But inodes don't record what subvolume they're in - they can't, because
if they did we'd have to update every single inode within a subvolume
when taking a snapshot in order to keep that field up to date. So it
needs to be tracked in memory, based on how we got to that inode.

Hence this patch adds a subvolume field to ei_inode_info, and switches
to iget5() so we can index by it in the inode hash table.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/fs/bcachefs/fs.h b/fs/bcachefs/fs.h
index c08a828d66cd..6dae425bf616 100644
--- a/fs/bcachefs/fs.h
+++ b/fs/bcachefs/fs.h
@@ -44,10 +44,20 @@ struct bch_inode_info {
 	struct mutex		ei_quota_lock;
 	struct bch_qid		ei_qid;
 
+	u32			ei_subvol;
+
 	/* copy of inode in btree: */
 	struct bch_inode_unpacked ei_inode;
 };
 
+static inline subvol_inum inode_inum(struct bch_inode_info *inode)
+{
+	return (subvol_inum) {
+		.subvol	= inode->ei_subvol,
+		.inum	= inode->ei_inode.bi_inum,
+	};
+}
+
 /*
  * Set if we've gotten a btree error for this inode, and thus the vfs inode and
  * btree inode may be inconsistent:
@@ -153,7 +163,7 @@ static inline int bch2_set_projid(struct bch_fs *c,
 				      KEY_TYPE_QUOTA_PREALLOC);
 }
 
-struct inode *bch2_vfs_inode_get(struct bch_fs *, u64);
+struct inode *bch2_vfs_inode_get(struct bch_fs *, subvol_inum);
 
 /* returns 0 if we want to do the update, or error is passed up */
 typedef int (*inode_set_fn)(struct bch_inode_info *,