Issue with JFFS2 and a_ops->dirty_folio
Jean-Michel Hautbois
jeanmichel.hautbois at yoseli.org
Fri Jun 14 03:21:23 PDT 2024
Hi there,
On 13/06/2024 13:20, Christoph Hellwig wrote:
> On Thu, Jun 13, 2024 at 09:05:17AM +0200, Jean-Michel Hautbois wrote:
>> Hi everyone !
>>
>> I am currently working on a Coldfire (MPC54418) and quite everything goes
>> well, except that I can only execute one command from user space before
>> getting a segmentation fault on the do_exit() syscall.
>
> Looks like jffs2 is simply missing a dirty_folio implementation. The
> simple filemap_dirty_folio should do the job, please try the patch
> below:
>
>
> diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
> index 62ea76da7fdf23..7124cbad6c35ae 100644
> --- a/fs/jffs2/file.c
> +++ b/fs/jffs2/file.c
> @@ -19,6 +19,7 @@
> #include <linux/highmem.h>
> #include <linux/crc32.h>
> #include <linux/jffs2.h>
> +#include <linux/writeback.h>
> #include "nodelist.h"
>
> static int jffs2_write_end(struct file *filp, struct address_space *mapping,
> @@ -75,6 +76,7 @@ const struct address_space_operations jffs2_file_address_operations =
> .read_folio = jffs2_read_folio,
> .write_begin = jffs2_write_begin,
> .write_end = jffs2_write_end,
> + .dirty_folio = filemap_dirty_folio,
> };
>
> static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
I managed to modify my rootfs and I am using ubifs. It is far more
complete and indeed an error occurs in the ubifs_dirty_folio() call. I
don't know if there is any interest there, but the volume is mounted
read-only on purpose:
[ 4.490000] ubi0: attaching mtd5
[ 4.500000] ubi0: MTD device 5 is write-protected, attach in
read-only mode
[ 4.890000] ubi0: scanning is finished
[ 4.940000] ubi0 warning: autoresize: skip auto-resize because of R/O
mode
[ 4.950000] ubi0: attached mtd5 (name "root2", size 64 MiB)
[ 4.960000] ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976
bytes
[ 4.960000] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 2048
[ 4.970000] ubi0: VID header offset: 2048 (aligned 2048), data
offset: 4096
[ 4.980000] ubi0: good PEBs: 512, bad PEBs: 0, corrupted PEBs: 0
[ 4.980000] ubi0: user volume: 1, internal volumes: 1, max. volumes
count: 128
[ 4.990000] ubi0: max/mean erase counter: 0/0, WL threshold: 4096,
image sequence number: 1619801263
[ 5.000000] ubi0: available PEBs: 215, total reserved PEBs: 297, PEBs
reserved for bad PEB handling: 80
[ 5.010000] ubi0: background thread "ubi_bgt0d" started, PID 25
[ 5.020000] UBIFS (ubi0:0): read-only UBI device
[ 5.030000] UBIFS (ubi0:0): Mounting in unauthenticated mode
[ 5.130000] UBIFS (ubi0:0): UBIFS: mounted UBI device 0, volume 0,
name "root2", R/O mode
[ 5.140000] UBIFS (ubi0:0): LEB size: 126976 bytes (124 KiB),
min./max. I/O unit sizes: 2048 bytes/2048 bytes
[ 5.150000] UBIFS (ubi0:0): FS size: 25649152 bytes (24 MiB, 202
LEBs), max 2048 LEBs, journal size 9023488 bytes (8 MiB, 72 LEBs)
[ 5.160000] UBIFS (ubi0:0): reserved for root: 0 bytes (0 KiB)
[ 5.160000] UBIFS (ubi0:0): media format: w4/r0 (latest is w5/r0),
UUID 43E9BD53-C843-4AEE-897E-5684A795D2C8, small LPT model
[ 5.180000] VFS: Mounted root (ubifs filesystem) readonly on device 0:13.
And when I execute a command:
bash-5.2# ls
bin etc lib32 mnt root sys
12.560000] UBIFS error (ubi0:0 pid 26): ubifs_assert_failed: UBIFS
assert failed: ret == false, in fs/ubifs/file.c:1477
4mus[ 12.570000] UBIFS warning (ubi0:0 pid 26): ubifs_ro_mode:
switched to read-only mode, error -22
r 12.580000] CPU: 0 PID: 26 Comm: ls Not tainted
6.10.0-rc3stmark2-001-00024-gc73f39277b30-dirty #455
[ 12.580000] Stack from 42937dac:
[ 12.580000] 42937dac 414a3f4c 414a3f4c 4fed4a01 41dda000
420885cc 413e2b20 414a3f4c
[ 12.580000] 41115112 41dda000 ffffffea 414b3c43 000005c5
4fed4a98 6015e000 4105e058
[ 12.580000] 420885cc 4fed4a98 415ed419 42937f12 4107ae8a
4fed4a98 00000000 ffffffff
[ 12.580000] fffffffe 42937e96 60162000 00000001 413c03ce
4107aa9e 4107ea74 00000001
[ 12.580000] 42909034 ffffffff 42940600 60162000 42940600
428c0450 42936000 428c048c
[ 12.580000] 00000000 00000000 00000000 00000000 42937f54
4107b19c 42937f12 42909034
[ 12.580000] Call Trace: [<413e2b20>] dump_stack+0xc/0x10
[ 12.580000] [<41115112>] ubifs_dirty_folio+0x3e/0x4a
[ 12.580000] [<4105e058>] folio_mark_dirty+0x6e/0x82
[ 12.580000] [<4107ae8a>] unmap_page_range+0x3ec/0x68a
[ 12.580000] [<413c03ce>] mas_find+0x0/0xfa
[ 12.580000] [<4107aa9e>] unmap_page_range+0x0/0x68a
[ 12.580000] [<4107ea74>] vma_next+0x0/0x14
[ 12.580000] [<4107b19c>] unmap_vmas+0x74/0x98
[ 12.580000] [<4102cc68>] up_read+0x0/0x2a
[ 12.580000] [<41080c14>] exit_mmap+0xd4/0x1d2
[ 12.580000] [<410098ff>] will_become_orphaned_pgrp+0x27/0x7c
[ 12.580000] [<413e6eb4>] _raw_spin_unlock_irq+0x0/0x14
[ 12.580000] [<41006db0>] __mmput+0x2e/0xa0
[ 12.580000] [<4100a7ae>] do_exit+0x264/0x764
[ 12.580000] [<413e6ec4>] _raw_spin_unlock_irq+0x10/0x14
[ 12.580000] [<4100adfe>] do_group_exit+0x26/0x78
[ 12.580000] [<4100ae50>] sys_exit_group+0x0/0x14
[ 12.580000] [<4100ae64>] pid_child_should_wake+0x0/0x56
[ 12.580000] [<41005918>] system_call+0x54/0xa8
[ 12.580000]
[ 17.600000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:1016
[ 17.610000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: !c->ro_media && !c->ro_mount, in fs/ubifs/journal.c:108
[ 17.620000] UBIFS error (ubi0:0 pid 24): make_reservation: cannot
reserve 4144 bytes in jhead 2, error -30
[ 17.630000] UBIFS error (ubi0:0 pid 24): do_writepage: cannot write
folio 150 of inode 156, error -30
[ 17.640000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:944
[ 17.650000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: c->bi.dd_growth >= 0, in fs/ubifs/budget.c:550
[ 26.440000] UBIFS error (ubi0:0 pid 27): ubifs_assert_failed: UBIFS
assert failed: ret == false, in fs/ubifs/file.c:1477
[ 26.450000] UBIFS error (ubi0:0 pid 27): ubifs_assert_failed: UBIFS
assert failed: ret == false, in fs/ubifs/file.c:1477
[ 26.460000] UBIFS error (ubi0:0 pid 27): ubifs_assert_failed: UBIFS
assert failed: ret == false, in fs/ubifs/file.c:1477
[ 31.520000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:1016
[ 31.530000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: !c->ro_media && !c->ro_mount, in fs/ubifs/journal.c:108
[ 31.540000] UBIFS error (ubi0:0 pid 24): make_reservation: cannot
reserve 4144 bytes in jhead 2, error -30
[ 31.550000] UBIFS error (ubi0:0 pid 24): do_writepage: cannot write
folio 101 of inode 81, error -30
[ 31.560000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:944
[ 31.570000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: c->bi.dd_growth >= 0, in fs/ubifs/budget.c:550
[ 36.640000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:1016
[ 36.650000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: !c->ro_media && !c->ro_mount, in fs/ubifs/journal.c:108
[ 36.660000] UBIFS error (ubi0:0 pid 24): make_reservation: cannot
reserve 4144 bytes in jhead 2, error -30
[ 36.670000] UBIFS error (ubi0:0 pid 24): do_writepage: cannot write
folio 102 of inode 81, error -30
[ 36.680000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:944
[ 36.690000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: c->bi.dd_growth >= 0, in fs/ubifs/budget.c:550
[ 36.700000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:1016
[ 36.710000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: !c->ro_media && !c->ro_mount, in fs/ubifs/journal.c:108
[ 36.720000] UBIFS error (ubi0:0 pid 24): make_reservation: cannot
reserve 4144 bytes in jhead 2, error -30
[ 36.730000] UBIFS error (ubi0:0 pid 24): do_writepage: cannot write
folio 150 of inode 156, error -30
[ 36.740000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: folio->private != NULL, in fs/ubifs/file.c:944
[ 36.750000] UBIFS error (ubi0:0 pid 24): ubifs_assert_failed: UBIFS
assert failed: c->bi.dd_growth >= 0, in fs/ubifs/budget.c:550
From now on, nothing happens anymore.
What can cause this ? I see in the file.c:
"An attempt to dirty a page without budgeting for it - should not happen."
So, why can it happen :-) ?
Thanks a lot !
BR,
JM
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