Re: [PATCH] nfs: Fix mismatch between encode_dent_fn and filldir_t
From: Neil Brown
Date: Wed Jan 24 2007 - 19:36:46 EST
On Wednesday January 17, paubert@xxxxxxx wrote:
> The 5th parameter of filldir_t function type used by vfs_readdir
> was changed from ino_t to u64 in October. Unfortunately the patch
> missed some files in fs/nfsd where functions pointers of type
> encode_dent_fn are passed around and finally cast to filldir_t.
>
> The effect is only visible when an NFS server is run on a 32 bit
> big-endian machine (it would have been visible on all 32 bit
> architectures if the 6th parameter had been used). The results
> are interesting: all files have an inode of 0 (unique you say?)
> from getdents(2) and even ls(1) does not find any files.
>
Thanks a lot for this.
I agree that the function pointer cast is bad, and I think it is best
to get rid of it entirely. This means changing the first arg of
*_encode_entry to be a 'void *', but I think the benefits are worth
the cost.
So I've modified your patch to do this and also fixed the nfsv4 code.
I'll get it into 2.6.20 and 2.6.19.x
Thanks,
NeilBrown
----------------------
Fix type mismatch with filldir_t used by nfsd.
nfsd defines a type 'encode_dent_fn' which is much like 'filldir_t'
except that the first pointer is 'struct readdir_cd *' rather than
'void *'. It then casts encode_dent_fn points to 'filldir_t' as
needed. This hides any other type mismatches between the two such as
the fact that the 'ino' arg recently changed from ino_t to u64.
So: get rid of 'encode_dent_fn', get rid of the cast of the function
type, change the first arg of various functions from 'struct readdir_cd *'
to 'void *', and live with the fact that we have a little less type
checking on the calling of these functions now.
Less internal (to nfsd) checking offset by more external checking, which
is more important.
Thanks to Gabriel Paubert <paubert@xxxxxxx> for discovering this and
providing an initial patch.
Signed-off-by: Gabriel Paubert <paubert@xxxxxxx>
Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./fs/nfsd/nfs3xdr.c | 9 +++++----
./fs/nfsd/nfs4xdr.c | 5 +++--
./fs/nfsd/nfsxdr.c | 5 +++--
./fs/nfsd/vfs.c | 4 ++--
./include/linux/nfsd/nfsd.h | 4 +---
./include/linux/nfsd/xdr.h | 4 ++--
./include/linux/nfsd/xdr3.h | 8 ++++----
7 files changed, 20 insertions(+), 19 deletions(-)
diff .prev/fs/nfsd/nfs3xdr.c ./fs/nfsd/nfs3xdr.c
--- .prev/fs/nfsd/nfs3xdr.c 2007-01-24 18:38:49.000000000 +1100
+++ ./fs/nfsd/nfs3xdr.c 2007-01-24 18:45:40.000000000 +1100
@@ -990,15 +990,16 @@ encode_entry(struct readdir_cd *ccd, con
}
int
-nfs3svc_encode_entry(struct readdir_cd *cd, const char *name,
- int namlen, loff_t offset, ino_t ino, unsigned int d_type)
+nfs3svc_encode_entry(void *cd, const char *name,
+ int namlen, loff_t offset, u64 ino, unsigned int d_type)
{
return encode_entry(cd, name, namlen, offset, ino, d_type, 0);
}
int
-nfs3svc_encode_entry_plus(struct readdir_cd *cd, const char *name,
- int namlen, loff_t offset, ino_t ino, unsigned int d_type)
+nfs3svc_encode_entry_plus(void *cd, const char *name,
+ int namlen, loff_t offset, u64 ino,
+ unsigned int d_type)
{
return encode_entry(cd, name, namlen, offset, ino, d_type, 1);
}
diff .prev/fs/nfsd/nfs4xdr.c ./fs/nfsd/nfs4xdr.c
--- .prev/fs/nfsd/nfs4xdr.c 2007-01-22 09:08:18.000000000 +1100
+++ ./fs/nfsd/nfs4xdr.c 2007-01-24 18:44:19.000000000 +1100
@@ -1880,9 +1880,10 @@ nfsd4_encode_rdattr_error(__be32 *p, int
}
static int
-nfsd4_encode_dirent(struct readdir_cd *ccd, const char *name, int namlen,
- loff_t offset, ino_t ino, unsigned int d_type)
+nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
{
+ struct readdir_cd *ccd = ccdv;
struct nfsd4_readdir *cd = container_of(ccd, struct nfsd4_readdir, common);
int buflen;
__be32 *p = cd->buffer;
diff .prev/fs/nfsd/nfsxdr.c ./fs/nfsd/nfsxdr.c
--- .prev/fs/nfsd/nfsxdr.c 2007-01-24 18:33:50.000000000 +1100
+++ ./fs/nfsd/nfsxdr.c 2007-01-24 18:37:33.000000000 +1100
@@ -462,9 +462,10 @@ nfssvc_encode_statfsres(struct svc_rqst
}
int
-nfssvc_encode_entry(struct readdir_cd *ccd, const char *name,
- int namlen, loff_t offset, ino_t ino, unsigned int d_type)
+nfssvc_encode_entry(void *ccdv, const char *name,
+ int namlen, loff_t offset, u64 ino, unsigned int d_type)
{
+ struct readdir_cd *ccd = ccdv;
struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
__be32 *p = cd->buffer;
int buflen, slen;
diff .prev/fs/nfsd/vfs.c ./fs/nfsd/vfs.c
--- .prev/fs/nfsd/vfs.c 2007-01-23 11:15:06.000000000 +1100
+++ ./fs/nfsd/vfs.c 2007-01-24 18:32:10.000000000 +1100
@@ -1720,7 +1720,7 @@ out:
*/
__be32
nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,
- struct readdir_cd *cdp, encode_dent_fn func)
+ struct readdir_cd *cdp, filldir_t func)
{
__be32 err;
int host_err;
@@ -1745,7 +1745,7 @@ nfsd_readdir(struct svc_rqst *rqstp, str
do {
cdp->err = nfserr_eof; /* will be cleared on successful read */
- host_err = vfs_readdir(file, (filldir_t) func, cdp);
+ host_err = vfs_readdir(file, func, cdp);
} while (host_err >=0 && cdp->err == nfs_ok);
if (host_err)
err = nfserrno(host_err);
diff .prev/include/linux/nfsd/nfsd.h ./include/linux/nfsd/nfsd.h
--- .prev/include/linux/nfsd/nfsd.h 2007-01-22 09:08:17.000000000 +1100
+++ ./include/linux/nfsd/nfsd.h 2007-01-25 10:31:56.000000000 +1100
@@ -52,8 +52,6 @@
struct readdir_cd {
__be32 err; /* 0, nfserr, or nfserr_eof */
};
-typedef int (*encode_dent_fn)(struct readdir_cd *, const char *,
- int, loff_t, ino_t, unsigned int);
typedef int (*nfsd_dirop_t)(struct inode *, struct dentry *, int, int);
extern struct svc_program nfsd_program;
@@ -117,7 +115,7 @@ __be32 nfsd_unlink(struct svc_rqst *, s
int nfsd_truncate(struct svc_rqst *, struct svc_fh *,
unsigned long size);
__be32 nfsd_readdir(struct svc_rqst *, struct svc_fh *,
- loff_t *, struct readdir_cd *, encode_dent_fn);
+ loff_t *, struct readdir_cd *, filldir_t);
__be32 nfsd_statfs(struct svc_rqst *, struct svc_fh *,
struct kstatfs *);
diff .prev/include/linux/nfsd/xdr3.h ./include/linux/nfsd/xdr3.h
--- .prev/include/linux/nfsd/xdr3.h 2007-01-24 18:40:06.000000000 +1100
+++ ./include/linux/nfsd/xdr3.h 2007-01-24 18:41:45.000000000 +1100
@@ -331,11 +331,11 @@ int nfs3svc_release_fhandle(struct svc_r
struct nfsd3_attrstat *);
int nfs3svc_release_fhandle2(struct svc_rqst *, __be32 *,
struct nfsd3_fhandle_pair *);
-int nfs3svc_encode_entry(struct readdir_cd *, const char *name,
- int namlen, loff_t offset, ino_t ino,
+int nfs3svc_encode_entry(void *, const char *name,
+ int namlen, loff_t offset, u64 ino,
unsigned int);
-int nfs3svc_encode_entry_plus(struct readdir_cd *, const char *name,
- int namlen, loff_t offset, ino_t ino,
+int nfs3svc_encode_entry_plus(void *, const char *name,
+ int namlen, loff_t offset, u64 ino,
unsigned int);
/* Helper functions for NFSv3 ACL code */
__be32 *nfs3svc_encode_post_op_attr(struct svc_rqst *rqstp, __be32 *p,
diff .prev/include/linux/nfsd/xdr.h ./include/linux/nfsd/xdr.h
--- .prev/include/linux/nfsd/xdr.h 2007-01-24 18:34:11.000000000 +1100
+++ ./include/linux/nfsd/xdr.h 2007-01-24 18:45:54.000000000 +1100
@@ -165,8 +165,8 @@ int nfssvc_encode_readres(struct svc_rqs
int nfssvc_encode_statfsres(struct svc_rqst *, __be32 *, struct nfsd_statfsres *);
int nfssvc_encode_readdirres(struct svc_rqst *, __be32 *, struct nfsd_readdirres *);
-int nfssvc_encode_entry(struct readdir_cd *, const char *name,
- int namlen, loff_t offset, ino_t ino, unsigned int);
+int nfssvc_encode_entry(void *, const char *name,
+ int namlen, loff_t offset, u64 ino, unsigned int);
int nfssvc_release_fhandle(struct svc_rqst *, __be32 *, struct nfsd_fhandle *);
-
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