nfs: Fix mismatch between encode_dent_fn and filldir_t

PATCH In review Gabriel Paubert 2 participants 2 messages Jan 17, 2007 – Jan 25, 2007 NFS server

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Gabriel Paubert

author

2007-01-17 19:32 UTC #0 lore raw

PATCH 1/1 nfs: Fix mismatch between encode_dent_fn and filldir_t

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.

Signed-off-by Gabriel Paubert <[email protected]>

P.S.: this shows that function pointer casts are evil, but I did not find a simpler way to fix this.

fs/nfsd/nfs3xdr.c +2 -2

index 277df40..20c5f4a 100644
@@ -991,14 +991,14 @@ encode_entry(struct readdir_cd *ccd, const char *name,
 
 int
 nfs3svc_encode_entry(struct readdir_cd *cd, const char *name,
-		     int namlen, loff_t offset, ino_t ino, unsigned int d_type)
+		     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)
+			  int namlen, loff_t offset, u64 ino, unsigned int d_type)
 {
 	return encode_entry(cd, name, namlen, offset, ino, d_type, 1);
 }

fs/nfsd/nfsxdr.c +1 -1

index f5243f9..244406e 100644
@@ -463,7 +463,7 @@ nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p,
 
 int
 nfssvc_encode_entry(struct readdir_cd *ccd, const char *name,
-		    int namlen, loff_t offset, ino_t ino, unsigned int d_type)
+		    int namlen, loff_t offset, u64 ino, unsigned int d_type)
 {
 	struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
 	__be32	*p = cd->buffer;

include/linux/nfsd/nfsd.h +1 -1

index 0727774..3ba5141 100644
@@ -53,7 +53,7 @@ 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);
+						int, loff_t, u64, unsigned int);
 typedef int (*nfsd_dirop_t)(struct inode *, struct dentry *, int, int);
 
 extern struct svc_program	nfsd_program;

include/linux/nfsd/xdr.h +1 -1

index 877192d..328520c 100644
@@ -166,7 +166,7 @@ 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 namlen, loff_t offset, u64 ino, unsigned int);
 
 int nfssvc_release_fhandle(struct svc_rqst *, __be32 *, struct nfsd_fhandle *);

include/linux/nfsd/xdr3.h +2 -2

index 7996386..bc8b171 100644
@@ -332,10 +332,10 @@ int nfs3svc_release_fhandle(struct svc_rqst *, __be32 *,
 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 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 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,

Neil Brown

2007-01-25 00:36 UTC #1 lore raw

Quoted 11 lines · On Wednesday January 17, [email protected] 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 <[email protected]> for discovering this and providing an initial patch.

Signed-off-by Gabriel Paubert <[email protected]>

Signed-off-by Neil Brown <[email protected]>

### 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(-)

fs/nfsd/nfs3xdr.c +5 -4

diff .prev/fs/nfsd/nfs3xdr.c ./fs/nfsd/nfs3xdr.c
@@ -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);
 }

fs/nfsd/nfs4xdr.c +3 -2

diff .prev/fs/nfsd/nfs4xdr.c ./fs/nfsd/nfs4xdr.c
@@ -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;

fs/nfsd/nfsxdr.c +3 -2

diff .prev/fs/nfsd/nfsxdr.c ./fs/nfsd/nfsxdr.c
@@ -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;

fs/nfsd/vfs.c +2 -2

diff .prev/fs/nfsd/vfs.c ./fs/nfsd/vfs.c
@@ -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);

include/linux/nfsd/nfsd.h +1 -3

diff .prev/include/linux/nfsd/nfsd.h ./include/linux/nfsd/nfsd.h
@@ -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 *);

include/linux/nfsd/xdr3.h +4 -4

diff .prev/include/linux/nfsd/xdr3.h ./include/linux/nfsd/xdr3.h
@@ -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,

include/linux/nfsd/xdr.h +2 -2

diff .prev/include/linux/nfsd/xdr.h ./include/linux/nfsd/xdr.h
@@ -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 *);