Date:	Thu, 29 Jan 2009 02:29:11 +0530
From:	Ankit Jain <me@...itjain.org>
To:	Al Viro <viro@...iv.linux.org.uk>
CC:	Christoph Hellwig <hch@...radead.org>,
	linux-fsdevel@...r.kernel.org, mfasheh@...e.com,
	joel.becker@...cle.com, ocfs2-devel@....oracle.com,
	linux-kernel@...r.kernel.org, xfs-masters@....sgi.com,
	xfs@....sgi.com
Subject: [PATCH] fs: Add new pre-allocation ioctls to vfs for compatibility
 with legacy xfs ioctls

Al, Could this be included in the vfs queue?

This patch adds ioctls to vfs for compatibility with legacy XFS
pre-allocation ioctls (XFS_IOC_*RESVP*). The implementation
effectively invokes sys_fallocate for the new ioctls.
Also handles the compat_ioctl case.
Note: These legacy ioctls are also implemented by OCFS2.

Signed-off-by: Ankit Jain <me@...itjain.org>
Reviewed-by: Christoph Hellwig <hch@....de>
Tested-by: Christoph Hellwig <hch@....de>
---
 fs/compat_ioctl.c      |   29 +++++++++++++++++++++++++++
 fs/ioctl.c             |   35 ++++++++++++++++++++++++++++++++
 fs/open.c              |   51 +++++++++++++++++++++++------------------------
 include/linux/falloc.h |   44 +++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h     |    6 +++++
 5 files changed, 139 insertions(+), 26 deletions(-)

Index: xfs/fs/compat_ioctl.c
===================================================================
--- xfs.orig/fs/compat_ioctl.c	2009-01-21 21:03:26.217449883 +0100
+++ xfs/fs/compat_ioctl.c	2009-01-27 20:36:59.189424147 +0100
@@ -2765,6 +2765,26 @@ static void compat_ioctl_error(struct fi
 		free_page((unsigned long)path);
 }
 
+#ifdef BROKEN_X86_ALIGNMENT
+/* just account for different alignment */
+static unsigned long copy_to_space_resv(unsigned long arg)
+{
+	struct space_resv_32	__user *p32 = (void __user *)arg;
+	struct space_resv		__user *p = compat_alloc_user_space(sizeof(*p));
+
+	if (copy_in_user(&p->l_type,	&p32->l_type,	sizeof(s16)) ||
+	    copy_in_user(&p->l_whence,	&p32->l_whence, sizeof(s16)) ||
+	    copy_in_user(&p->l_start,	&p32->l_start,	sizeof(s64)) ||
+	    copy_in_user(&p->l_len,	&p32->l_len,	sizeof(s64)) ||
+	    copy_in_user(&p->l_sysid,	&p32->l_sysid,	sizeof(s32)) ||
+	    copy_in_user(&p->l_pid,	&p32->l_pid,	sizeof(u32)) ||
+	    copy_in_user(&p->l_pad,	&p32->l_pad,	4*sizeof(u32)))
+		return -EFAULT;
+
+	return (unsigned long)p;
+}
+#endif
+
 asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
 				unsigned long arg)
 {
@@ -2795,6 +2815,15 @@ asmlinkage long compat_sys_ioctl(unsigne
 	case FIOQSIZE:
 		break;
 
+	case F_IOC_RESVSP_32:
+	case F_IOC_RESVSP64_32:
+#ifdef BROKEN_X86_ALIGNMENT
+		arg = copy_to_space_resv(arg);
+		cmd = _NATIVE_IOC(cmd, struct space_resv);
+#endif
+		error = ioctl_preallocate(filp, arg);
+		goto out_fput;
+
 	case FIBMAP:
 	case FIGETBSZ:
 	case FIONREAD:
Index: xfs/fs/ioctl.c
===================================================================
--- xfs.orig/fs/ioctl.c	2009-01-21 21:03:27.321448363 +0100
+++ xfs/fs/ioctl.c	2009-01-27 20:36:59.189424147 +0100
@@ -15,6 +15,7 @@
 #include <linux/uaccess.h>
 #include <linux/writeback.h>
 #include <linux/buffer_head.h>
+#include <linux/falloc.h>
 
 #include <asm/ioctls.h>
 
@@ -370,6 +371,37 @@ EXPORT_SYMBOL(generic_block_fiemap);
 
 #endif  /*  CONFIG_BLOCK  */
 
+/*
+ * This provides compatibility with legacy XFS pre-allocation ioctls
+ * which predate the fallocate syscall.
+ *
+ * Only the l_start, l_len and l_whence fields of the 'struct space_resv'
+ * are used here, rest are ignored.
+ */
+int ioctl_preallocate(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct space_resv sr;
+
+	if (copy_from_user(&sr, (struct space_resv __user *) arg, sizeof(sr)))
+		return -EFAULT;
+
+	switch (sr.l_whence) {
+	case SEEK_SET:
+		break;
+	case SEEK_CUR:
+		sr.l_start += filp->f_pos;
+		break;
+	case SEEK_END:
+		sr.l_start += i_size_read(inode);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return do_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
+}
+
 static int file_ioctl(struct file *filp, unsigned int cmd,
 		unsigned long arg)
 {
@@ -385,6 +417,9 @@ static int file_ioctl(struct file *filp,
 		return put_user(inode->i_sb->s_blocksize, p);
 	case FIONREAD:
 		return put_user(i_size_read(inode) - filp->f_pos, p);
+	case F_IOC_RESVSP:
+	case F_IOC_RESVSP64:
+		return ioctl_preallocate(filp, arg);
 	}
 
 	return vfs_ioctl(filp, cmd, arg);
Index: xfs/fs/open.c
===================================================================
--- xfs.orig/fs/open.c	2009-01-21 21:03:27.740294372 +0100
+++ xfs/fs/open.c	2009-01-27 20:41:38.208298998 +0100
@@ -377,63 +377,63 @@ SYSCALL_ALIAS(sys_ftruncate64, SyS_ftrun
 #endif
 #endif /* BITS_PER_LONG == 32 */
 
-SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
+
+int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 {
-	struct file *file;
-	struct inode *inode;
-	long ret = -EINVAL;
+	struct inode *inode = file->f_path.dentry->d_inode;
+	long ret;
 
 	if (offset < 0 || len <= 0)
-		goto out;
+		return -EINVAL;
 
 	/* Return error if mode is not supported */
-	ret = -EOPNOTSUPP;
 	if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
-		goto out;
+		return -EOPNOTSUPP;
 
-	ret = -EBADF;
-	file = fget(fd);
-	if (!file)
-		goto out;
 	if (!(file->f_mode & FMODE_WRITE))
-		goto out_fput;
+		return -EBADF;
 	/*
 	 * Revalidate the write permissions, in case security policy has
 	 * changed since the files were opened.
 	 */
 	ret = security_file_permission(file, MAY_WRITE);
 	if (ret)
-		goto out_fput;
+		return ret;
 
-	inode = file->f_path.dentry->d_inode;
-
-	ret = -ESPIPE;
 	if (S_ISFIFO(inode->i_mode))
-		goto out_fput;
+		return -ESPIPE;
 
-	ret = -ENODEV;
 	/*
 	 * Let individual file system decide if it supports preallocation
 	 * for directories or not.
 	 */
 	if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
-		goto out_fput;
+		return -ENODEV;
 
-	ret = -EFBIG;
 	/* Check for wrap through zero too */
 	if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
-		goto out_fput;
+		return -EFBIG;
 
-	if (inode->i_op->fallocate)
-		ret = inode->i_op->fallocate(inode, mode, offset, len);
-	else
-		ret = -EOPNOTSUPP;
+	if (!inode->i_op->fallocate)
+		return -EOPNOTSUPP;
 
-out_fput:
-	fput(file);
-out:
-	return ret;
+	return inode->i_op->fallocate(inode, mode, offset, len);
 }
+
+SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
+{
+	struct file *file;
+	int error = -EBADF;
+
+	file = fget(fd);
+	if (file) {
+		error = do_fallocate(file, mode, offset, len);
+		fput(file);
+	}
+
+	return error;
+}
+
 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
 asmlinkage long SyS_fallocate(long fd, long mode, loff_t offset, loff_t len)
 {
Index: xfs/include/linux/falloc.h
===================================================================
--- xfs.orig/include/linux/falloc.h	2009-01-21 21:03:28.076324621 +0100
+++ xfs/include/linux/falloc.h	2009-01-27 20:36:59.190423995 +0100
@@ -3,4 +3,48 @@
 
 #define FALLOC_FL_KEEP_SIZE	0x01 /* default is extend size */
 
+#ifdef __KERNEL__
+
+/*
+ * Space reservation ioctls and argument structure
+ * are designed to be compatible with the legacy XFS ioctls.
+ */
+struct space_resv {
+	__s16		l_type;
+	__s16		l_whence;
+	__s64		l_start;
+	__s64		l_len;		/* len == 0 means until end of file */
+	__s32		l_sysid;
+	__u32		l_pid;
+	__s32		l_pad[4];	/* reserve area			    */
+};
+
+#define F_IOC_RESVSP		_IOW('X', 40, struct space_resv)
+#define F_IOC_RESVSP64		_IOW('X', 42, struct space_resv)
+
+#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
+#define BROKEN_X86_ALIGNMENT
+
+#define  _NATIVE_IOC(cmd, type) \
+	  _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(type))
+
+/* on ia32 l_start is on a 32-bit boundary */
+struct space_resv_32 {
+	__s16		l_type;
+	__s16		l_whence;
+	__s64		l_start	__attribute__((packed));
+			/* len == 0 means until end of file */
+	__s64		l_len __attribute__((packed));
+	__s32		l_sysid;
+	__u32		l_pid;
+	__s32		l_pad[4];	/* reserve area */
+};
+
+#define F_IOC_RESVSP_32		_IOW('X', 40, struct space_resv_32)
+#define F_IOC_RESVSP64_32	_IOW('X', 42, struct space_resv_32)
+
+#endif
+
+#endif /* __KERNEL__ */
+
 #endif /* _FALLOC_H_ */
Index: xfs/include/linux/fs.h
===================================================================
--- xfs.orig/include/linux/fs.h	2009-01-24 17:58:48.960904090 +0100
+++ xfs/include/linux/fs.h	2009-01-27 20:42:01.675299140 +0100
@@ -1694,6 +1694,8 @@ static inline int break_lease(struct ino
 
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 		       struct file *filp);
+extern int do_fallocate(struct file *file, int mode, loff_t offset,
+			loff_t len);
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
 			int mode);
 extern struct file *filp_open(const char *, int, int);
@@ -1702,6 +1704,10 @@ extern struct file * dentry_open(struct 
 extern int filp_close(struct file *, fl_owner_t id);
 extern char * getname(const char __user *);
 
+/* fs/ioctl.c */
+
+extern int ioctl_preallocate(struct file *filp, unsigned long arg);
+
 /* fs/dcache.c */
 extern void __init vfs_caches_init_early(void);
 extern void __init vfs_caches_init(unsigned long);
--
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