Re: [f2fs-dev] [PATCH] f2fs: get parent inode when recovering pino

Jaegeuk Kim
2020-05-05T19:08:33Z

On 05/05, Eric Biggers wrote:
> On Tue, May 05, 2020 at 11:49:32AM -0700, Jaegeuk Kim wrote:
> > How about this?
> >
> > From 2a6b0e53e592854306062a2dc35db2d8f79062f2 Mon Sep 17 00:00:00 2001
> > From: Jaegeuk Kim <jaegeuk@kernel.org>
> > Date: Tue, 5 May 2020 11:33:29 -0700
> > Subject: [PATCH] f2fs: find a living dentry when finding parent ino
> >
> > We need to check any dentry still alive to get parent inode number.
> >
> > Suggested-by: Eric Biggers <ebiggers@kernel.org>
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> > fs/f2fs/file.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index a0a4413d6083b..95139cb85faca 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -169,9 +169,8 @@ static int get_parent_ino(struct inode *inode, nid_t *pino)
> > {
> > struct dentry *dentry;
> >
> > - inode = igrab(inode);
> > - dentry = d_find_any_alias(inode);
> > - iput(inode);
> > + /* Need to check if valid dentry still exists. */
> > + dentry = d_find_alias(inode);
> > if (!dentry)
> > return 0;
> >
>
> It's fine, but it could use some more explanation. (What's a "valid dentry"?)
> How about the following?

Cool, I took this. Thanks,

>
> >From f8fe7d57eead1423e8548ac7a5ec881d701466a5 Mon Sep 17 00:00:00 2001
> From: Eric Biggers <ebiggers@google.com>
> Date: Tue, 5 May 2020 11:41:11 -0700
> Subject: [PATCH] f2fs: correctly fix the parent inode number during fsync()
>
> fsync() may be called on a deleted file that's still open. So when
> fsync() tries to set the parent inode number when the inode has
> LOST_PINO and i_nlink == 1 (to avoid later checkpoints), it needs to
> make sure to get the parent directory via a non-deleted alias.
>
> Also remove the unnecessary igrab() and iput(), as the caller already
> holds a reference to the inode.
>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
> fs/f2fs/file.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 6ab8f621a3c5a2..b3069188fd3478 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -165,9 +165,11 @@ static int get_parent_ino(struct inode *inode, nid_t *pino)
> {
> struct dentry *dentry;
>
> - inode = igrab(inode);
> - dentry = d_find_any_alias(inode);
> - iput(inode);
> + /*
> + * Make sure to get the non-deleted alias. The alias associated with
> + * the open file descriptor being fsync()'ed may be deleted already.
> + */
> + dentry = d_find_alias(inode);
> if (!dentry)
> return 0;
>
> --
> 2.26.2