fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls

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.

[AV: folded fixes from hch]

Signed-off-by: Ankit Jain <me@ankitjain.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 112 insertions, 29 deletions

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index c135202c38b3..626c7483b4de 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -31,6 +31,7 @@
 #include <linux/skbuff.h>
 #include <linux/netlink.h>
 #include <linux/vt.h>
+#include <linux/falloc.h>
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/ppp_defs.h>
@@ -1779,6 +1780,41 @@ lp_timeout_trans(unsigned int fd, unsigned int cmd, unsigned long arg)
         return sys_ioctl(fd, cmd, (unsigned long)tn);
 }
 
+/* on ia32 l_start is on a 32-bit boundary */
+#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
+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 FS_IOC_RESVSP_32                _IOW ('X', 40, struct space_resv_32)
+#define FS_IOC_RESVSP64_32      _IOW ('X', 42, struct space_resv_32)
+
+/* just account for different alignment */
+static int compat_ioctl_preallocate(struct file *file, 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 ioctl_preallocate(file, p);
+}
+#endif
+
 
 typedef int (*ioctl_trans_handler_t)(unsigned int, unsigned int,
                                         unsigned long, struct file *);
@@ -2756,6 +2792,18 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
         case FIOQSIZE:
                 break;
 
+#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
+        case FS_IOC_RESVSP_32:
+        case FS_IOC_RESVSP64_32:
+                error = compat_ioctl_preallocate(filp, arg);
+                goto out_fput;
+#else
+        case FS_IOC_RESVSP:
+        case FS_IOC_RESVSP64:
+                error = ioctl_preallocate(filp, (void __user *)arg);
+                goto out_fput;
+#endif
+
         case FIBMAP:
         case FIGETBSZ:
         case FIONREAD:
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 001f8d3118f2..5612880fcbe7 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -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>
 
@@ -403,6 +404,37 @@ 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, void __user *argp)
+{
+        struct inode *inode = filp->f_path.dentry->d_inode;
+        struct space_resv sr;
+
+        if (copy_from_user(&sr, argp, 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)
 {
@@ -414,6 +446,9 @@ static int file_ioctl(struct file *filp, unsigned int cmd,
                 return ioctl_fibmap(filp, p);
         case FIONREAD:
                 return put_user(i_size_read(inode) - filp->f_pos, p);
+        case FS_IOC_RESVSP:
+        case FS_IOC_RESVSP64:
+                return ioctl_preallocate(filp, p);
         }
 
         return vfs_ioctl(filp, cmd, arg);
diff --git a/fs/open.c b/fs/open.c
index 7200e23d9258..dd98e8076024 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -378,63 +378,63 @@ SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64);
 #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)
 {