ext4: avoid ENOSPC when avoiding to reuse recently deleted inodes

ext4: avoid ENOSPC when avoiding to reuse recently deleted inodes

When ext4 is running on a filesystem without a journal, it tries not to
reuse recently deleted inodes to provide better chances for filesystem
recovery in case of crash. However this logic forbids reuse of freed
inodes for up to 5 minutes and especially for filesystems with smaller
number of inodes can lead to ENOSPC errors returned when allocating new
inodes.

Fix the problem by allowing to reuse recently deleted inode if there's
no other inode free in the scanned range.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200318121317.31941-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>