rename operation is too heavy (experiencing a 12s FS/system lock )

[invoxiaamo]

We experience very long locking of the FS if we perform a single rename (more 12s)

The hardware is pretty solid:

• ARM @ 250+ MHz
• NOR spi @ 100 Mhz bus (octo SPI) - sector size in 4KB
• FS size : 32 MB

littlefs version 2.4.1 (issue also existing on 2.2.0)
Zephyr OS (but doesn't matter here)

Too simplify the issue and reproduce easily.

• erase the whole flash
• mount littlefs
• create 100 small files (256 bytes each)

Then in loop

• open("test", FS_O_CREATE | FS_O_WRITE)
• write(1024 bytes)
• close()
• rename("test", "test_rename")

Usually each rename of the loop requires 4000+ flash read operations (96K of data) and a single write, no erase.
BUT: every 33 loop, a single rename last 2s, requires ~300K flash read operations (4.7MB of data), a single sector erase, 7 writes.

... It looks to be a lot for a FS filled with 100 files and 26KB of data (the more files and/or data, the longer is the lock)

I will try to analyze what is done, but this scenario may sound a bell to the littlefs developers.
Arnaud

[invoxiaamo]

I miss the issue #327 .
Closing this one since look to be a duplicate o