Kill cached_lookup() and real_lookup() (6e6b1bd1) · Commits · e / devices / android_kernel_xiaomi_markw

fs/namei.c

+66 −87

Original line number	Diff line number	Diff line
		@@ -411,26 +411,6 @@ do_revalidate(struct dentry dentry, struct nameidata nd)
		return dentry;
		}

		/*
		* Internal lookup() using the new generic dcache.
		* SMP-safe
		*/
		static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
		{
		struct dentry * dentry = __d_lookup(parent, name);

		/* lockess __d_lookup may fail due to concurrent d_move()
		* in some unrelated directory, so try with d_lookup
		*/
		if (!dentry)
		dentry = d_lookup(parent, name);

		if (dentry && dentry->d_op && dentry->d_op->d_revalidate)
		dentry = do_revalidate(dentry, nd);

		return dentry;
		}

		/*
		* Short-cut version of permission(), for calling by
		* path_walk(), when dcache lock is held. Combines parts
		@@ -463,70 +443,6 @@ ok:
		return security_inode_permission(inode, MAY_EXEC);
		}

		/*
		* This is called when everything else fails, and we actually have
		* to go to the low-level filesystem to find out what we should do..
		*
		* We get the directory semaphore, and after getting that we also
		* make sure that nobody added the entry to the dcache in the meantime..
		* SMP-safe
		*/
		static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
		{
		struct dentry * result;
		struct inode *dir = parent->d_inode;

		mutex_lock(&dir->i_mutex);
		/*
		* First re-do the cached lookup just in case it was created
		* while we waited for the directory semaphore..
		*
		* FIXME! This could use version numbering or similar to
		* avoid unnecessary cache lookups.
		*
		* The "dcache_lock" is purely to protect the RCU list walker
		* from concurrent renames at this point (we mustn't get false
		* negatives from the RCU list walk here, unlike the optimistic
		* fast walk).
		*
		* so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
		*/
		result = d_lookup(parent, name);
		if (!result) {
		struct dentry *dentry;

		/* Don't create child dentry for a dead directory. */
		result = ERR_PTR(-ENOENT);
		if (IS_DEADDIR(dir))
		goto out_unlock;

		dentry = d_alloc(parent, name);
		result = ERR_PTR(-ENOMEM);
		if (dentry) {
		result = dir->i_op->lookup(dir, dentry, nd);
		if (result)
		dput(dentry);
		else
		result = dentry;
		}
		out_unlock:
		mutex_unlock(&dir->i_mutex);
		return result;
		}

		/*
		* Uhhuh! Nasty case: the cache was re-populated while
		* we waited on the semaphore. Need to revalidate.
		*/
		mutex_unlock(&dir->i_mutex);
		if (result->d_op && result->d_op->d_revalidate) {
		result = do_revalidate(result, nd);
		if (!result)
		result = ERR_PTR(-ENOENT);
		}
		return result;
		}

		static __always_inline void set_root(struct nameidata *nd)
		{
		if (!nd->root.mnt) {
		@@ -767,7 +683,8 @@ static int do_lookup(struct nameidata nd, struct qstr name,
		struct path *path)
		{
		struct vfsmount *mnt = nd->path.mnt;
		struct dentry *dentry;
		struct dentry dentry, parent;
		struct inode *dir;
		/*
		* See if the low-level filesystem might want
		* to use its own hash..
		@@ -790,7 +707,59 @@ done:
		return 0;

		need_lookup:
		dentry = real_lookup(nd->path.dentry, name, nd);
		parent = nd->path.dentry;
		dir = parent->d_inode;

		mutex_lock(&dir->i_mutex);
		/*
		* First re-do the cached lookup just in case it was created
		* while we waited for the directory semaphore..
		*
		* FIXME! This could use version numbering or similar to
		* avoid unnecessary cache lookups.
		*
		* The "dcache_lock" is purely to protect the RCU list walker
		* from concurrent renames at this point (we mustn't get false
		* negatives from the RCU list walk here, unlike the optimistic
		* fast walk).
		*
		* so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
		*/
		dentry = d_lookup(parent, name);
		if (!dentry) {
		struct dentry *new;

		/* Don't create child dentry for a dead directory. */
		dentry = ERR_PTR(-ENOENT);
		if (IS_DEADDIR(dir))
		goto out_unlock;

		new = d_alloc(parent, name);
		dentry = ERR_PTR(-ENOMEM);
		if (new) {
		dentry = dir->i_op->lookup(dir, new, nd);
		if (dentry)
		dput(new);
		else
		dentry = new;
		}
		out_unlock:
		mutex_unlock(&dir->i_mutex);
		if (IS_ERR(dentry))
		goto fail;
		goto done;
		}

		/*
		* Uhhuh! Nasty case: the cache was re-populated while
		* we waited on the semaphore. Need to revalidate.
		*/
		mutex_unlock(&dir->i_mutex);
		if (dentry->d_op && dentry->d_op->d_revalidate) {
		dentry = do_revalidate(dentry, nd);
		if (!dentry)
		dentry = ERR_PTR(-ENOENT);
		}
		if (IS_ERR(dentry))
		goto fail;
		goto done;
		@@ -1144,7 +1113,17 @@ static struct dentry __lookup_hash(struct qstr name,
		goto out;
		}

		dentry = cached_lookup(base, name, nd);
		dentry = __d_lookup(base, name);

		/* lockess __d_lookup may fail due to concurrent d_move()
		* in some unrelated directory, so try with d_lookup
		*/
		if (!dentry)
		dentry = d_lookup(base, name);

		if (dentry && dentry->d_op && dentry->d_op->d_revalidate)
		dentry = do_revalidate(dentry, nd);

		if (!dentry) {
		struct dentry *new;