[PATCH] read(v)/write(v) fixes

Clean up vfs_readv/writev() interface and avoid code duplication.

Make kNFSd use the cleaned-up interfaces, and disable the code that
accesses the low-level readpage() function of the exported filesystem
(not allowed - many filesystems need extra setup, which is why we have
a separate ->sendpage() routine for that).

3 files changed, 50 insertions, 131 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 3414a439f240..b22b34d7ba1e 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -572,6 +572,7 @@ found:
 	return ra;
 }
 
+#if 0 /* don't poke into fs code directly */
 /*
  * Grab and keep cached pages assosiated with a file in the svc_rqst
  * so that they can be passed to the netowork sendmsg/sendpage routines
@@ -626,6 +627,7 @@ nfsd_getpages(struct file *filp, struct svc_rqst *rqstp, unsigned long count)
 		retval = desc.error;
 	return retval;
 }
+#endif
 
 /*
  * Read data from a file. count must contain the requested read count
@@ -658,13 +660,16 @@ nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
 	if (ra)
 		file.f_ra = ra->p_ra;
 
+#if 0 /* don't poke into fs code directly */
 	if (inode->i_mapping->a_ops->readpage) {
 		file.f_pos = offset;
 		err = nfsd_getpages(&file, rqstp, *count);
-	} else {
+	} else
+#endif
+	{
 		oldfs = get_fs();
 		set_fs(KERNEL_DS);
-		err = vfs_readv(&file, vec, vlen, *count, &offset);
+		err = vfs_readv(&file, vec, vlen, &offset);
 		set_fs(oldfs);
 	}
 
@@ -740,7 +745,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
 
 	/* Write the data. */
 	oldfs = get_fs(); set_fs(KERNEL_DS);
-	err = vfs_writev(&file, vec, vlen, cnt, &offset);
+	err = vfs_writev(&file, vec, vlen, &offset);
 	if (err >= 0)
 		nfsdstats.io_write += cnt;
 	set_fs(oldfs);
diff --git a/fs/read_write.c b/fs/read_write.c
index ac9610241a66..a335041c98b8 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -207,53 +207,6 @@ ssize_t vfs_read(struct file *file, char *buf, size_t count, loff_t *pos)
 	return ret;
 }
 
-ssize_t vfs_readv(struct file *file, struct iovec *vec, int vlen, size_t count, loff_t *pos)
-{
-	struct inode *inode = file->f_dentry->d_inode;
-	ssize_t ret;
-
-	if (!(file->f_mode & FMODE_READ))
-		return -EBADF;
-	if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
-		return -EINVAL;
-
-	ret = locks_verify_area(FLOCK_VERIFY_READ, inode, file, *pos, count);
-	if (!ret) {
-		ret = security_ops->file_permission (file, MAY_READ);
-		if (!ret) {
-			if (file->f_op->readv)
-				ret = file->f_op->readv(file, vec, vlen, pos);
-			else {
-				/* do it by hand */
-				struct iovec *vector = vec;
-				ret = 0;
-				while (vlen > 0) {
-					void * base =  vector->iov_base;
-					size_t len = vector->iov_len;
-					ssize_t nr;
-					vector++;
-					vlen--;
-					if (file->f_op->read)
-						nr = file->f_op->read(file, base, len, pos);
-					else
-						nr = do_sync_read(file, base, len, pos);
-					if (nr < 0) {
-						if (!ret) ret = nr;
-						break;
-					}
-					ret += nr;
-					if (nr != len)
-						break;
-				}
-			}
-			if (ret > 0)
-				dnotify_parent(file->f_dentry, DN_ACCESS);
-		}
-	}
-
-	return ret;
-}
-
 ssize_t do_sync_write(struct file *filp, const char *buf, size_t len, loff_t *ppos)
 {
 	struct kiocb kiocb;
@@ -294,53 +247,6 @@ ssize_t vfs_write(struct file *file, const char *buf, size_t count, loff_t *pos)
 	return ret;
 }
 
-ssize_t vfs_writev(struct file *file, const struct iovec *vec, int vlen, size_t count, loff_t *pos)
-{
-	struct inode *inode = file->f_dentry->d_inode;
-	ssize_t ret;
-
-	if (!(file->f_mode & FMODE_WRITE))
-		return -EBADF;
-	if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
-		return -EINVAL;
-
-	ret = locks_verify_area(FLOCK_VERIFY_WRITE, inode, file, *pos, count);
-	if (!ret) {
-		ret = security_ops->file_permission (file, MAY_WRITE);
-		if (!ret) {
-			if (file->f_op->writev)
-				ret = file->f_op->writev(file, vec, vlen, pos);
-			else {
-				/* do it by hand */
-				const struct iovec *vector = vec;
-				ret = 0;
-				while (vlen > 0) {
-					void * base = vector->iov_base;
-					size_t len = vector->iov_len;
-					ssize_t nr;
-					vector++;
-					vlen--;
-					if (file->f_op->write)
-						nr = file->f_op->write(file, base, len, pos);
-					else
-						nr = do_sync_write(file, base, len, pos);
-					if (nr < 0) {
-						if (!ret) ret = nr;
-						break;
-					}
-					ret += nr;
-					if (nr != len)
-						break;
-				}
-			}
-			if (ret > 0)
-				dnotify_parent(file->f_dentry, DN_MODIFY);
-		}
-	}
-
-	return ret;
-}
-
 asmlinkage ssize_t sys_read(unsigned int fd, char * buf, size_t count)
 {
 	struct file *file;
@@ -427,7 +333,7 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
 
 static ssize_t do_readv_writev(int type, struct file *file,
 			       const struct iovec * vector,
-			       unsigned long nr_segs)
+			       unsigned long nr_segs, loff_t *pos)
 {
 	typedef ssize_t (*io_fn_t)(struct file *, char *, size_t, loff_t *);
 	typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);
@@ -496,7 +402,7 @@ static ssize_t do_readv_writev(int type, struct file *file,
 	/* VERIFY_WRITE actually means a read, as we write to user space */
 	ret = locks_verify_area((type == READ 
 				 ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE),
-				inode, file, file->f_pos, tot_len);
+				inode, file, *pos, tot_len);
 	if (ret)
 		goto out;
 
@@ -509,7 +415,7 @@ static ssize_t do_readv_writev(int type, struct file *file,
 		fnv = file->f_op->writev;
 	}
 	if (fnv) {
-		ret = fnv(file, iov, nr_segs, &file->f_pos);
+		ret = fnv(file, iov, nr_segs, pos);
 		goto out;
 	}
 
@@ -526,7 +432,7 @@ static ssize_t do_readv_writev(int type, struct file *file,
 		vector++;
 		nr_segs--;
 
-		nr = fn(file, base, len, &file->f_pos);
+		nr = fn(file, base, len, pos);
 
 		if (nr < 0) {
 			if (!ret) ret = nr;
@@ -545,50 +451,56 @@ out:
 	return ret;
 }
 
+ssize_t vfs_readv(struct file *file, const struct iovec *vec,
+		  unsigned long vlen, loff_t *pos)
+{
+	if (!(file->f_mode & FMODE_READ))
+		return -EBADF;
+	if (!file->f_op || (!file->f_op->readv && !file->f_op->read))
+		return -EINVAL;
 
-asmlinkage ssize_t
-sys_readv(unsigned long fd, const struct iovec *vector, unsigned long nr_segs)
+	return do_readv_writev(READ, file, vec, vlen, pos);
+}
+
+ssize_t vfs_writev(struct file *file, const struct iovec *vec,
+		   unsigned long vlen, loff_t *pos)
 {
-	struct file * file;
-	ssize_t ret;
+	if (!(file->f_mode & FMODE_WRITE))
+		return -EBADF;
+	if (!file->f_op || (!file->f_op->writev && !file->f_op->write))
+		return -EINVAL;
+
+	return do_readv_writev(WRITE, file, vec, vlen, pos);
+}
+
 
+asmlinkage ssize_t
+sys_readv(unsigned long fd, const struct iovec *vec, unsigned long vlen)
+{
+	struct file *file;
+	ssize_t ret = -EBADF;
 
-	ret = -EBADF;
 	file = fget(fd);
-	if (!file)
-		goto bad_file;
-	if (file->f_op && (file->f_mode & FMODE_READ) &&
-	    (file->f_op->readv || file->f_op->read)) {
-		ret = security_ops->file_permission (file, MAY_READ);
-		if (!ret)
-			ret = do_readv_writev(READ, file, vector, nr_segs);
+	if (file) {
+		ret = vfs_readv(file, vec, vlen, &file->f_pos);
+		fput(file);
 	}
-	fput(file);
 
-bad_file:
 	return ret;
 }
 
 asmlinkage ssize_t
-sys_writev(unsigned long fd, const struct iovec * vector, unsigned long nr_segs)
+sys_writev(unsigned long fd, const struct iovec *vec, unsigned long vlen)
 {
-	struct file * file;
-	ssize_t ret;
-
+	struct file *file;
+	ssize_t ret = -EBADF;
 
-	ret = -EBADF;
 	file = fget(fd);
-	if (!file)
-		goto bad_file;
-	if (file->f_op && (file->f_mode & FMODE_WRITE) &&
-	    (file->f_op->writev || file->f_op->write)) {
-		ret = security_ops->file_permission (file, MAY_WRITE);
-		if (!ret)
-			ret = do_readv_writev(WRITE, file, vector, nr_segs);
+	if (file) {
+		ret = vfs_writev(file, vec, vlen, &file->f_pos);
+		fput(file);
 	}
-	fput(file);
 
-bad_file:
 	return ret;
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4e0e4bd005a6..b71df992cad7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -793,8 +793,10 @@ struct seq_file;
 
 extern ssize_t vfs_read(struct file *, char *, size_t, loff_t *);
 extern ssize_t vfs_write(struct file *, const char *, size_t, loff_t *);
-extern ssize_t vfs_readv(struct file *, struct iovec *, int, size_t, loff_t *);
-extern ssize_t vfs_writev(struct file *, const struct iovec *, int, size_t, loff_t *);
+extern ssize_t vfs_readv(struct file *, const struct iovec *,
+		unsigned long, loff_t *);
+extern ssize_t vfs_writev(struct file *, const struct iovec *,
+		unsigned long, loff_t *);
 
 /*
  * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called