----- Original Message -----
> Since the kernel commit b93b016313b3ba8003c3b8bb71f569af91f19fc7
> ("page cache: use xa_lock") renamed the address_space ->page_tree
> to ->i_pages, without this patch, the "files -[cp]" options don't
> work on Linux 4.17 and later kernels.
> (In this case, is it OK not to add a new member to offset_table?)
Sure, that's fine.
>
> Also, it looks like the address_space's member that the "files -c"
> option really requires is ->nrpages, not ->page_tree.
Looks right to me.
I also noticed this is an attempt is made to dump the page cache contents
when nrpages count is 0:
crash> files -p ffff8803c8d67038
INODE NRPAGES
ffff8803c8d67038 0
files: do_radix_tree: callback operation failed: entry: 0 item: 0
crash>
So I added this:
--- filesys.c 2018-08-09 10:51:41.657042511 -0400
+++ filesys.c 2018-09-04 11:46:02.186072870 -0400
@@ -2207,6 +2207,11 @@ dump_inode_page_cache_info(ulong inode)
RJUST|LONG_DEC,
MKSTR(nrpages)));
+ FREEBUF(inode_buf);
+
+ if (!nrpages)
+ return;
+
root_rnode = i_mapping + OFFSET(address_space_page_tree);
rtp.index = 0;
rtp.value = (void *)&dump_inode_page;
@@ -2217,7 +2222,6 @@ dump_inode_page_cache_info(ulong inode)
error(INFO, "page_tree count: %ld nrpages: %ld\n",
count, nrpages);
- FREEBUF(inode_buf);
return;
}
But then again, I note that "files -p" fails quite frequently due to
some kind of mis-use of the contents of the radix tree. The 2 options
were introduced together in crash-7.1.2, but I've never really used them.
Anyway, the patch is queued for crash-7.2.4:
https://github.com/crash-utility/crash/commit/2f57a96ce27d8b121c2822de2a66c71b83bdad21
Thanks,
Dave
> Signed-off-by: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx>
> ---
> filesys.c | 2 +-
> memory.c | 2 ++
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/filesys.c b/filesys.c
> index 47f5a24..527b3f6 100644
> --- a/filesys.c
> +++ b/filesys.c
> @@ -2275,7 +2275,7 @@ cmd_files(void)
> return;
>
> case 'c':
> - if (VALID_MEMBER(address_space_page_tree) &&
> + if (VALID_MEMBER(address_space_nrpages) &&
> VALID_MEMBER(inode_i_mapping))
> open_flags |= PRINT_NRPAGES;
> else
> diff --git a/memory.c b/memory.c
> index 24fce5e..ea25047 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -487,6 +487,8 @@ vm_init(void)
> MEMBER_OFFSET_INIT(block_device_bd_disk, "block_device", "bd_disk");
> MEMBER_OFFSET_INIT(inode_i_mapping, "inode", "i_mapping");
> MEMBER_OFFSET_INIT(address_space_page_tree, "address_space", "page_tree");
> + if (INVALID_MEMBER(address_space_page_tree))
> + MEMBER_OFFSET_INIT(address_space_page_tree, "address_space", "i_pages");
> MEMBER_OFFSET_INIT(address_space_nrpages, "address_space", "nrpages");
> if (INVALID_MEMBER(address_space_nrpages))
> MEMBER_OFFSET_INIT(address_space_nrpages, "address_space", "__nrpages");
> --
> 1.8.3.1
>
> --
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