I am also struggling with JFFS2, and I did already a lot of tests.
There more files you have in jffs2, the longer it takes to mount:
- per inode, 16 B (static) or 24 B (dynamic) are written in RAM
- per file, more or less 72 B (found by testing, I should check the
jffs2 sources..) are written in RAM
Also, during mounting, a garbage collect is done. As explained below,
the file system (the journal) is then checked. And the bigger the
flash,
the more time it can take.
Indeed, once the boot time is long, you can only solve it by formatting
jffs2.
I can reproduce this this way: I put 1000 files in 1 directory, then I
delete 997 of them, and still mounting and also opening of 1 file takes
very long. To go more in detail: mounting goes from 11s to 10s, but
opening 1 file goes from 570ms to 820ms.