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Commit ca344a89 authored by Al Viro's avatar Al Viro
Browse files

do_last: unify may_open() call and everyting after it 



We have a bunch of diverging codepaths in do_last(); some of
them converge, but the case of having to create a new file
duplicates large part of common tail of the rest and exits
separately.  Massage them so that they could be merged.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9b44f1b3

fs/namei.c

+22 −37
Original line number Diff line number Diff line
@@ -2114,7 +2114,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
			    const struct open_flags *op, const char *pathname)

{

	struct dentry *dir = nd->path.dentry;

	int open_flag = op->open_flag;

	int will_truncate;

	int want_write = 0;

	int skip_perm = 0;

	struct file *filp;

	struct inode *inode;

	int error;
@@ -2138,7 +2141,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
		if (error)

			goto exit;

		audit_inode(pathname, nd->path.dentry);

		if (op->open_flag & O_CREAT) {

		if (open_flag & O_CREAT) {

			error = -EISDIR;

			goto exit;

		}
@@ -2152,7 +2155,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
		goto ok;

	}



	if (!(op->open_flag & O_CREAT)) {

	if (!(open_flag & O_CREAT)) {

		if (nd->last.name[nd->last.len])

			nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;

		/* we _can_ be in RCU mode here */
@@ -2230,28 +2233,15 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
		error = mnt_want_write(nd->path.mnt);

		if (error)

			goto exit_mutex_unlock;

		error = __open_namei_create(nd, path, op->open_flag, op->mode);

		if (error) {

			mnt_drop_write(nd->path.mnt);

		want_write = 1;

		will_truncate = 0;

		error = __open_namei_create(nd, path, open_flag, op->mode);

		if (error)

			goto exit;

		}

		/* Don't check for write permission, don't truncate */

		error = may_open(&nd->path, 0, op->open_flag & ~O_TRUNC);

		if (error) {

			mnt_drop_write(nd->path.mnt);

			goto exit;

		}

		filp = nameidata_to_filp(nd);

		mnt_drop_write(nd->path.mnt);

		path_put(&nd->path);

		if (!IS_ERR(filp)) {

			error = ima_file_check(filp, op->acc_mode);

			if (error) {

				fput(filp);

				filp = ERR_PTR(error);

			}

		}

		return filp;

		open_flag &= ~O_TRUNC;

		skip_perm = 1;

		goto common;

	}



	/*
@@ -2261,7 +2251,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
	audit_inode(pathname, path->dentry);



	error = -EEXIST;

	if (op->open_flag & O_EXCL)

	if (open_flag & O_EXCL)

		goto exit_dput;



	error = follow_managed(path, nd->flags);
@@ -2281,18 +2271,17 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
	if (S_ISDIR(nd->inode->i_mode))

		goto exit;

ok:

	will_truncate = open_will_truncate(op->open_flag, nd->path.dentry->d_inode);

	will_truncate = open_will_truncate(open_flag, nd->path.dentry->d_inode);

	if (will_truncate) {

		error = mnt_want_write(nd->path.mnt);

		if (error)

			goto exit;

		want_write = 1;

	}

	error = may_open(&nd->path, op->acc_mode, op->open_flag);

	if (error) {

		if (will_truncate)

			mnt_drop_write(nd->path.mnt);

common:

	error = may_open(&nd->path, skip_perm ? 0 : op->acc_mode, open_flag);

	if (error)

		goto exit;

	}

	filp = nameidata_to_filp(nd);

	if (!IS_ERR(filp)) {

		error = ima_file_check(filp, op->acc_mode);
@@ -2310,12 +2299,8 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
			}

		}

	}

	/*

	 * It is now safe to drop the mnt write

	 * because the filp has had a write taken

	 * on its behalf.

	 */

	if (will_truncate)

out:

	if (want_write)

		mnt_drop_write(nd->path.mnt);

	path_put(&nd->path);

	return filp;
@@ -2325,8 +2310,8 @@ static struct file *do_last(struct nameidata *nd, struct path *path, 
exit_dput:

	path_put_conditional(path, nd);

exit:

	path_put(&nd->path);

	return ERR_PTR(error);

	filp = ERR_PTR(error);

	goto out;

}



static struct file *path_openat(int dfd, const char *pathname,