Re: [PATCH] f2fs: don't traverse directory blocks after EOF

[Chao Yu]

On 2024/7/26 0:55, Jaegeuk Kim wrote:
> On 07/12, Chao Yu wrote:
> > All directory blocks are within the scope of i_size, so let's limit
> > the end_block to just check valid dirent blocks.
>
> Do we really need this?

f2fs_readdir() and f2fs_empty_dir() uses dir_blocks() for upper boundary,
this patch aligns find_in_level() w/ them.

Also, it can avoid grabbing never used page cache across EOF.

So, we can consider taking this patch?

Thanks,

> > Meanwhile, it uses dir_blocks() instead of variable for cleanup in
> > __f2fs_find_entry().
> >
> > Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
> > ---
> >   fs/f2fs/dir.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> > index 02c9355176d3..d4591c215f07 100644
> > --- a/fs/f2fs/dir.c
> > +++ b/fs/f2fs/dir.c
> > @@ -305,18 +305,21 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir,
> >   	int s = GET_DENTRY_SLOTS(fname->disk_name.len);
> >   	unsigned int nbucket, nblock;
> >   	unsigned int bidx, end_block;
> > +	unsigned long last_block;
> >   	struct page *dentry_page;
> >   	struct f2fs_dir_entry *de = NULL;
> >   	pgoff_t next_pgofs;
> >   	bool room = false;
> >   	int max_slots;
> >   
> > +	last_block = dir_blocks(dir);
> >   	nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level);
> >   	nblock = bucket_blocks(level);
> >   
> >   	bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level,
> >   			       le32_to_cpu(fname->hash) % nbucket);
> >   	end_block = bidx + nblock;
> > +	end_block = min_t(unsigned int, end_block, last_block);
> >   
> >   	while (bidx < end_block) {
> >   		/* no need to allocate new dentry pages to all the indices */
> > @@ -361,7 +364,6 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
> >   					 const struct f2fs_filename *fname,
> >   					 struct page **res_page)
> >   {
> > -	unsigned long npages = dir_blocks(dir);
> >   	struct f2fs_dir_entry *de = NULL;
> >   	unsigned int max_depth;
> >   	unsigned int level;
> > @@ -373,7 +375,7 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
> >   		goto out;
> >   	}
> >   
> > -	if (npages == 0)
> > +	if (dir_blocks(dir) == 0)
> >   		goto out;
> >   
> >   	max_depth = F2FS_I(dir)->i_current_depth;
> > --
> > 2.40.1