On Sun, May 12, 2013 at 10:46:27PM -0500, Chris Fries wrote:
> From: Chris Fries <c.fr...@motorola.com>
>
> Panic loops while running LTP fsstress has been able to get
> a disk into two different panic loops from dec_valid_node_count.
> f2fs.h:714 BUG_ON(sbi->total_valid_node_count < count);
This is interesting catch.
from the code, dec_valid_node_count() is only called by truncate_node():
dec_valid_node_count(sbi, dn->inode, 1);
So the failure in your test means that sbi->total_valid_node_count < 1,
i.e. equal to 0. This should be an unexpected status.
I think a better solution should be to avoid such over truncate_node situation.
How do you think?
> Once, it happens during recovery itself, and the disk would cause
> a panic every time it mounted.
>
> Another time, it would happen during garbage collection, so the disk
> would cause a panic within 200 seconds of mounting.
>
> Removing this BUG_ON hasn't shown any side effects, so let's take it
> out and monitor.
>
> Signed-off-by: Chris Fries <c.fr...@motorola.com>
>
> ---
> fs/f2fs/f2fs.h | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index e80a87c..b8e9679 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -722,9 +722,21 @@ static inline void dec_valid_node_count(struct
> f2fs_sb_info *sbi,
> {
> spin_lock(&sbi->stat_lock);
>
> - BUG_ON(sbi->total_valid_block_count < count);
> - BUG_ON(sbi->total_valid_node_count < count);
> - BUG_ON(inode->i_blocks < count);
> + if (sbi->total_valid_block_count < count) {
> + WARN(1, "F2FS: total_valid_block_count too small- %d vs %d\n",
> + (unsigned int)sbi->total_valid_block_count, count);
> + count = sbi->total_valid_block_count;
> + }
> + if (sbi->total_valid_node_count < count) {
> + WARN(1, "F2FS: total_valid_node_count too small- %d vs %d\n",
> + sbi->total_valid_node_count, count);
> + count = sbi->total_valid_node_count;
> + }
> + if (inode->i_blocks < count) {
> + WARN(1, "F2FS: inode->i_blocks too small - %d vs %d\n",
> + (unsigned int)inode->i_blocks, count);
> + count = sbi->total_valid_node_count;
> + }
>
> inode->i_blocks -= count;
> sbi->total_valid_node_count -= count;
> --
> 1.8.0
>
> --
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