nilfs2: do not propagate ENOENT error from nilfs_btree_propagate()

nilfs2: do not propagate ENOENT error from nilfs_btree_propagate()

In preparation for writing logs, in nilfs_btree_propagate(), which makes
parent and ancestor node blocks dirty starting from a modified data block
or b-tree node block, if the starting block does not belong to the b-tree,
i.e.  is isolated, nilfs_btree_do_lookup() called within the function
fails with -ENOENT.

In this case, even though -ENOENT is an internal code, it is propagated to
the log writer via nilfs_bmap_propagate() and may be erroneously returned
to system calls such as fsync().

Fix this issue by changing the error code to -EINVAL in this case, and
having the bmap layer detect metadata corruption and convert the error
code appropriately.

Link: https://lkml.kernel.org/r/20250428173808.6452-3-konishi.ryusuke@gmail.com
Fixes: 1f5abe7e7dbc ("nilfs2: replace BUG_ON and BUG calls triggerable from ioctl")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Wentao Liang <vulab@iscas.ac.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>