1 files changed, 59 insertions, 0 deletions

diff --git a/fs/open.c b/fs/open.c
index be6a457f4226..a6b054edacba 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -26,6 +26,7 @@
 #include <linux/syscalls.h>
 #include <linux/rcupdate.h>
 #include <linux/audit.h>
+#include <linux/falloc.h>
 
 int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
@@ -352,6 +353,64 @@ asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
 }
 #endif
 
+asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len)
+{
+        struct file *file;
+        struct inode *inode;
+        long ret = -EINVAL;
+
+        if (offset < 0 || len <= 0)
+                goto out;
+
+        /* Return error if mode is not supported */
+        ret = -EOPNOTSUPP;
+        if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
+                goto out;
+
+        ret = -EBADF;
+        file = fget(fd);
+        if (!file)
+                goto out;
+        if (!(file->f_mode & FMODE_WRITE))
+                goto out_fput;
+        /*
+         * 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;
+
+        inode = file->f_path.dentry->d_inode;
+
+        ret = -ESPIPE;
+        if (S_ISFIFO(inode->i_mode))
+                goto out_fput;
+
+        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;
+
+        ret = -EFBIG;
+        /* Check for wrap through zero too */
+        if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
+                goto out_fput;
+
+        if (inode->i_op && inode->i_op->fallocate)
+                ret = inode->i_op->fallocate(inode, mode, offset, len);
+        else
+                ret = -ENOSYS;
+
+out_fput:
+        fput(file);
+out:
+        return ret;
+}
+
 /*
  * access() needs to use the real uid/gid, not the effective uid/gid.
  * We do this by temporarily clearing all FS-related capabilities and