Copy up a file when opened with write permissions. Does not copy up
the file data when O_TRUNC is specified.
---
fs/namei.c | 28 ++++++++++++++++++++++++++++
1 files changed, 28 insertions(+), 0 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index a6f7d5d..85a5451 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1929,6 +1929,24 @@ exit:
return ERR_PTR(error);
}
+static int open_union_copyup(struct nameidata *nd, struct path *path,
+ int open_flag)
+{
+ struct vfsmount *oldmnt = path->mnt;
+ int error;
+
+ if (open_flag & O_TRUNC)
+ error = union_copyup_len(nd, path, 0);
+ else
+ error = union_copyup(nd, path);
+ if (error)
+ return error;
+ if (oldmnt != path->mnt)
+ mntput(nd->path.mnt);
+
+ return error;
+}
+
static struct file *do_last(struct nameidata *nd, struct path *path,
int open_flag, int acc_mode,
int mode, const char *pathname,
@@ -1979,6 +1997,11 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
error = -ENOTDIR;
if (*want_dir && !path->dentry->d_inode->i_op->lookup)
goto exit_dput;
+ if (acc_mode & MAY_WRITE) {
+ error = open_union_copyup(nd, path, open_flag);
+ if (error)
+ goto exit_dput;
+ }
path_to_nameidata(path, nd);
audit_inode(pathname, nd->path.dentry);
goto ok;
@@ -2050,6 +2073,11 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
if (path->dentry->d_inode->i_op->follow_link)
return NULL;
+ if (acc_mode & MAY_WRITE) {
+ error = open_union_copyup(nd, path, open_flag);
+ if (error)
+ goto exit_dput;
+ }
path_to_nameidata(path, nd);
error = -EISDIR;
if (S_ISDIR(path->dentry->d_inode->i_mode))
--
1.6.3.3
--
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