System hangs on logfs umount

[David Wagner <david.wagner@free-electrons.com>]

	Hello,

I'm trying to use logfs (I'm supposed to benchmark several flash FS,
including logfs) but am facing a complete system hang: no panic, no
kernel message, the umount shell call just doesn't return and I can't do
anything anymore through the serial port.

The card I'm running it on is the igepv2 (or "igep0020") ; the flash has
2KiB pages and 128KiB EBs. (I tried with config_mtd_onenand_2x_program,
which simulates 4096/256KiB, but then, syncing also causes a system hang).

I turned on full logfs debugging:
-#define LOGFS_DEBUG            (0x01)
+#define LOGFS_DEBUG            LOGFS_DEBUG_ALL
but the logs don't event print:
    log_super("LogFS: Start unmounting\n");

Here is what appears to be logged when unmounting:
Jan  1 00:07:00 buildroot user.debug kernel: [  425.028472]
move_inode_to_page(1, 11, 0)
Jan  1 00:07:00 buildroot user.debug kernel: [  425.029388]
logfs_open_area(d, 7)
Jan  1 00:07:00 buildroot user.debug kernel: [  425.032165]
logfs_segment_write(1, 10, 7) 0->1a0018 0->101c
Jan  1 00:07:00 buildroot user.debug kernel: [  425.032440]
logfs_open_area(e, 6)
Jan  1 00:07:00 buildroot user.debug kernel: [  425.033447]
logfs_segment_write(1, 11, 6) 0->1c0018 0->e4
Jan  1 00:07:00 buildroot user.debug kernel: [  425.034149]
logfs_open_area(f, 0)
Jan  1 00:07:00 buildroot user.debug kernel: [  425.035156]
logfs_segment_write(2, 1, 0) 0->1e0018 0->126
Jan  1 00:07:00 buildroot user.debug kernel: [  425.035339]
move_inode_to_page(1, 2, 0)
Jan  1 00:07:00 buildroot user.debug kernel: [  425.035827]
logfs_segment_write(1, 2, 6) e00fc->1c00fc 0->e4
Jan  1 00:07:00 buildroot user.debug kernel: [  425.035919]
logfs_segment_delete(1, 2, 6) e00fc->1c00fc 0->e4
Jan  1 00:07:04 buildroot user.debug kernel: [  429.063415] UBI DBG (pid
533): ubi_leb_write: write 2048 bytes to LEB 0:45:114688
Jan  1 00:07:04 buildroot user.debug kernel: [  429.067108] UBI DBG (pid
533): ubi_leb_write: write 2048 bytes to LEB 0:45:116736
Jan  1 00:07:04 buildroot user.debug kernel: [  429.075439] UBI DBG (pid
533): ubi_leb_write: write 2048 bytes to LEB 0:45:118784
Jan  1 00:07:04 buildroot user.debug kernel: [  429.080810] UBI DBG (pid
533): ubi_leb_write: write 2048 bytes to LEB 0:45:120832


Do anyone have any clue ?

@Jörn:
I couldn't clone the git repository and logfsprogs is nowhere else to be
found ; the webgit interface makes it possible to get a snapshot tarball
but it's not as convenient.

Regards,
David.

-- 
David Wagner, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com