xfs: check if an inode is cached and allocated

Check the inode cache for a particular inode number.  If it's in the
cache, check that it's not currently being reclaimed.  If it's not being
reclaimed, return zero if the inode is allocated.  This function will be
used by various scrubbers to decide if the cache is more up to date
than the disk in terms of checking if an inode is allocated.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/xfs_icache.h

@@ -47,6 +47,7 @@ struct xfs_eofblocks {
 #define XFS_IGET_CREATE		0x1
 #define XFS_IGET_UNTRUSTED	0x2
 #define XFS_IGET_DONTCACHE	0x4
+#define XFS_IGET_INCORE		0x8	/* don't read from disk or reinit */
 
 /*
  * flags for AG inode iterator
@@ -126,4 +127,7 @@ xfs_fs_eofblocks_from_user(
 	return 0;
 }
 
+int xfs_icache_inode_is_allocated(struct xfs_mount *mp, struct xfs_trans *tp,
+				  xfs_ino_t ino, bool *inuse);
+
 #endif