RE: [f2fs-dev] [PATCH v2] f2fs: fix up f2fs_get_parent issue toretrieve correct parent inode number

[ììë]

Sorry, I've missed too. Forget this, please.

> -----Original Message-----
> From: ììë [mailto:cm224.lee@xxxxxxxxxxx]
> Sent: Friday, December 14, 2012 8:09 AM
> To: 'Namjae Jeon'; jaegeuk.kim@xxxxxxxxxxx
> Cc: 'Namjae Jeon'; linux-fsdevel@xxxxxxxxxxxxxxx; 'Amit Sahrawat'; linux-
> kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [f2fs-dev] [PATCH v2] f2fs: fix up f2fs_get_parent issue to
> retrieve correct parent inode number
> 
> 
> 
> > -----Original Message-----
> > From: Namjae Jeon [mailto:linkinjeon@xxxxxxxxx]
> > Sent: Thursday, December 13, 2012 11:44 PM
> > To: jaegeuk.kim@xxxxxxxxxxx
> > Cc: Namjae Jeon; Amit Sahrawat; Namjae Jeon; linux-kernel@xxxxxxxxxxxxxxx;
> > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx
> > Subject: [f2fs-dev] [PATCH v2] f2fs: fix up f2fs_get_parent issue to
> > retrieve correct parent inode number
> >
> > From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> >
> > Test Case:
> > [NFS Client]
> > ls -lR .
> >
> > [NFS Server]
> > while [ 1 ]
> > do
> > echo 3 > /proc/sys/vm/drop_caches
> > done
> >
> > Error on NFS Client: "No such file or directory"
> >
> > When cache is dropped at the server, it results in lookup failure at the
> > NFS client due to non-connection with the parent. The default path is it
> > initiates a lookup by calculating the hash value for the name, even
> though
> > the hash values stored on the disk for "." and ".." is maintained as zero,
> > which results in failure from find_in_block due to not matching HASH
> values.
> > Fix up, by using the correct hashing values for these entries.
> >
> > Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> > Signed-off-by: Amit Sahrawat <a.sahrawat@xxxxxxxxxxx>
> > Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>
> > ---
> >  fs/f2fs/dir.c  |    4 ++--
> >  fs/f2fs/hash.c |    4 ++++
> >  2 files changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> > index b4e24f3..a158406 100644
> > --- a/fs/f2fs/dir.c
> > +++ b/fs/f2fs/dir.c
> > @@ -540,13 +540,13 @@ int f2fs_make_empty(struct inode *inode, struct
> inode
> > *parent)
> >
> >  	de = &dentry_blk->dentry[0];
> >  	de->name_len = cpu_to_le16(1);
> > -	de->hash_code = 0;
> > +	de->hash_code = f2fs_dentry_hash(".", 1);
> >  	de->ino = cpu_to_le32(inode->i_ino);
> >  	memcpy(dentry_blk->filename[0], ".", 1);
> >  	set_de_type(de, inode);
> >
> >  	de = &dentry_blk->dentry[1];
> > -	de->hash_code = 0;
> > +	de->hash_code = f2fs_dentry_hash("..", 2);
> >  	de->name_len = cpu_to_le16(2);
> >  	de->ino = cpu_to_le32(parent->i_ino);
> >  	memcpy(dentry_blk->filename[1], "..", 2);
> > diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
> > index a60f042..5e48bac 100644
> > --- a/fs/f2fs/hash.c
> > +++ b/fs/f2fs/hash.c
> > @@ -76,6 +76,10 @@ f2fs_hash_t f2fs_dentry_hash(const char *name, int len)
> >  	const char *p;
> >  	__u32 in[8], buf[4];
> >
> > +	if ((len <= 2) && (name[0] == '.') &&
> > +		(name[1] == '.' || name[1] == '\0'))
> > +		return 0;
> > +
> 
> How about this?
> if (!memcmp(name, ".", len) || !memcmp(name, "..", len))
> 	return 0;
> 
> 
> >  	/* Initialize the default seed for the hash checksum functions */
> >  	buf[0] = 0x67452301;
> >  	buf[1] = 0xefcdab89;
> > --
> > 1.7.9.5
> >
> >
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> 
> 
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