Commit c2a8418d authored by Al Viro's avatar Al Viro Committed by sanglipeng
Browse files

saner calling conventions for unlazy_child() 

stable inclusion
from stable-v5.10.162
commit 36ec31201a3da85a112dd368be04aee05c713459
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7P7OH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=36ec31201a3da85a112dd368be04aee05c713459



--------------------------------

[ Upstream commit ae66db45 ]

same as for the previous commit - instead of 0/-ECHILD make
it return true/false, rename to try_to_unlazy_child().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarsanglipeng <sanglipeng1@jd.com>
parent bc08878b

fs/namei.c

+14 −14
Original line number Diff line number Diff line
@@ -719,19 +719,19 @@ static bool try_to_unlazy(struct nameidata *nd) 
}



/**

 * unlazy_child - try to switch to ref-walk mode.

 * try_to_unlazy_next - try to switch to ref-walk mode.

 * @nd: nameidata pathwalk data

 * @dentry: child of nd->path.dentry

 * @seq: seq number to check dentry against

 * Returns: 0 on success, -ECHILD on failure

 * @dentry: next dentry to step into

 * @seq: seq number to check @dentry against

 * Returns: true on success, false on failure

 *

 * unlazy_child attempts to legitimize the current nd->path, nd->root and dentry

 * for ref-walk mode.  @dentry must be a path found by a do_lookup call on

 * @nd.  Must be called from rcu-walk context.

 * Nothing should touch nameidata between unlazy_child() failure and

 * Similar to to try_to_unlazy(), but here we have the next dentry already

 * picked by rcu-walk and want to legitimize that in addition to the current

 * nd->path and nd->root for ref-walk mode.  Must be called from rcu-walk context.

 * Nothing should touch nameidata between try_to_unlazy_next() failure and

 * terminate_walk().

 */

static int unlazy_child(struct nameidata *nd, struct dentry *dentry, unsigned seq)

static bool try_to_unlazy_next(struct nameidata *nd, struct dentry *dentry, unsigned seq)

{

	BUG_ON(!(nd->flags & LOOKUP_RCU));
@@ -761,7 +761,7 @@ static int unlazy_child(struct nameidata *nd, struct dentry *dentry, unsigned se 
	if (unlikely(!legitimize_root(nd)))

		goto out_dput;

	rcu_read_unlock();

	return 0;

	return true;



out2:

	nd->path.mnt = NULL;
@@ -769,11 +769,11 @@ static int unlazy_child(struct nameidata *nd, struct dentry *dentry, unsigned se 
	nd->path.dentry = NULL;

out:

	rcu_read_unlock();

	return -ECHILD;

	return false;

out_dput:

	rcu_read_unlock();

	dput(dentry);

	return -ECHILD;

	return false;

}



static inline int d_revalidate(struct dentry *dentry, unsigned int flags)
@@ -1390,7 +1390,7 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, 
			return -ENOENT;

		if (likely(__follow_mount_rcu(nd, path, inode, seqp)))

			return 0;

		if (unlazy_child(nd, dentry, seq))

		if (!try_to_unlazy_next(nd, dentry, seq))

			return -ECHILD;

		// *path might've been clobbered by __follow_mount_rcu()

		path->mnt = nd->path.mnt;
@@ -1511,7 +1511,7 @@ static struct dentry *lookup_fast(struct nameidata *nd, 
		status = d_revalidate(dentry, nd->flags);

		if (likely(status > 0))

			return dentry;

		if (unlazy_child(nd, dentry, seq))

		if (!try_to_unlazy_next(nd, dentry, seq))

			return ERR_PTR(-ECHILD);

		if (unlikely(status == -ECHILD))

			/* we'd been told to redo it in non-rcu mode */