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-rw-r--r--fs/open.c59
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