X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fopen.c;h=a1450086e92f87e64007351ab673bf6274037e70;hb=db43a282d3ec92ea45109c5551fff3dcc5afef02;hp=4d690e33446f854f960645a1b57258e133dd5e11;hpb=9ac9b8474c39c3ae2c2b37d8e1f08db8a9146124;p=linux-2.6

diff --git a/fs/open.c b/fs/open.c
index 4d690e3344..a1450086e9 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -7,6 +7,7 @@
 #include <linux/string.h>
 #include <linux/mm.h>
 #include <linux/file.h>
+#include <linux/fdtable.h>
 #include <linux/quotaops.h>
 #include <linux/fsnotify.h>
 #include <linux/module.h>
@@ -459,8 +460,17 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
 	if(res || !(mode & S_IWOTH) ||
 	   special_file(nd.path.dentry->d_inode->i_mode))
 		goto out_path_release;
-
-	if(IS_RDONLY(nd.path.dentry->d_inode))
+	/*
+	 * This is a rare case where using __mnt_is_readonly()
+	 * is OK without a mnt_want/drop_write() pair.  Since
+	 * no actual write to the fs is performed here, we do
+	 * not need to telegraph to that to anyone.
+	 *
+	 * By doing this, we accept that this access is
+	 * inherently racy and know that the fs may change
+	 * state before we even see this result.
+	 */
+	if (__mnt_is_readonly(nd.path.mnt))
 		res = -EROFS;
 
 out_path_release:
@@ -797,6 +807,8 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 		error = __get_file_write_access(inode, mnt);
 		if (error)
 			goto cleanup_file;
+		if (!special_file(inode->i_mode))
+			file_take_write(f);
 	}
 
 	f->f_mapping = inode->i_mapping;
@@ -826,7 +838,7 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 	if (f->f_flags & O_DIRECT) {
 		if (!f->f_mapping->a_ops ||
 		    ((!f->f_mapping->a_ops->direct_IO) &&
-		    (!f->f_mapping->a_ops->get_xip_page))) {
+		    (!f->f_mapping->a_ops->get_xip_mem))) {
 			fput(f);
 			f = ERR_PTR(-EINVAL);
 		}
@@ -838,8 +850,16 @@ cleanup_all:
 	fops_put(f->f_op);
 	if (f->f_mode & FMODE_WRITE) {
 		put_write_access(inode);
-		if (!special_file(inode->i_mode))
+		if (!special_file(inode->i_mode)) {
+			/*
+			 * We don't consider this a real
+			 * mnt_want/drop_write() pair
+			 * because it all happenend right
+			 * here, so just reset the state.
+			 */
+			file_reset_write(f);
 			mnt_drop_write(mnt);
+		}
 	}
 	file_kill(f);
 	f->f_path.dentry = NULL;