xfs: hide xfs_inode_is_allocated in scrub common code

This function is only used by online fsck, so let's move it there.
In the next patch, we'll fix it to work properly and to require that the
caller hold the AGI buffer locked.  No major changes aside from
adjusting the signature a bit.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index 82d2a85d6461..3ba329526266 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -1230,3 +1230,40 @@ xchk_fsgates_enable(
 
 	sc->flags |= scrub_fsgates;
 }
+
+/*
+ * Decide if this is this a cached inode that's also allocated.
+ *
+ * Look up an inode by number in the given file system.  If the inode is
+ * in cache and isn't in purgatory, return 1 if the inode is allocated
+ * and 0 if it is not.  For all other cases (not in cache, being torn
+ * down, etc.), return a negative error code.
+ *
+ * The caller has to prevent inode allocation and freeing activity,
+ * presumably by locking the AGI buffer.   This is to ensure that an
+ * inode cannot transition from allocated to freed until the caller is
+ * ready to allow that.  If the inode is in an intermediate state (new,
+ * reclaimable, or being reclaimed), -EAGAIN will be returned; if the
+ * inode is not in the cache, -ENOENT will be returned.  The caller must
+ * deal with these scenarios appropriately.
+ *
+ * This is a specialized use case for the online scrubber; if you're
+ * reading this, you probably want xfs_iget.
+ */
+int
+xchk_inode_is_allocated(
+	struct xfs_scrub	*sc,
+	xfs_ino_t		ino,
+	bool			*inuse)
+{
+	struct xfs_inode	*ip;
+	int			error;
+
+	error = xfs_iget(sc->mp, sc->tp, ino, XFS_IGET_INCORE, 0, &ip);
+	if (error)
+		return error;
+
+	*inuse = !!(VFS_I(ip)->i_mode);
+	xfs_irele(ip);
+	return 0;
+}