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Commit 9abca360 authored by Nick Piggin's avatar Nick Piggin
Browse files

fs: increase d_name lock coverage 



Cover d_name with d_lock in more cases, where there may be concurrent
modification to it.

Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
parent b23fb0a6

fs/dcache.c

+12 −2
Original line number Diff line number Diff line
@@ -1350,6 +1350,11 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry, 
	list_for_each_entry(alias, &inode->i_dentry, d_alias) {

		struct qstr *qstr = &alias->d_name;



		/*

		 * Don't need alias->d_lock here, because aliases with

		 * d_parent == entry->d_parent are not subject to name or

		 * parent changes, because the parent inode i_mutex is held.

		 */

		if (qstr->hash != hash)

			continue;

		if (alias->d_parent != entry->d_parent)
@@ -2313,7 +2318,9 @@ static int prepend_path(const struct path *path, struct path *root, 
		}

		parent = dentry->d_parent;

		prefetch(parent);

		spin_lock(&dentry->d_lock);

		error = prepend_name(buffer, buflen, &dentry->d_name);

		spin_unlock(&dentry->d_lock);

		if (!error)

			error = prepend(buffer, buflen, "/", 1);

		if (error)
@@ -2515,10 +2522,13 @@ static char *__dentry_path(struct dentry *dentry, char *buf, int buflen) 


	while (!IS_ROOT(dentry)) {

		struct dentry *parent = dentry->d_parent;

		int error;



		prefetch(parent);

		if ((prepend_name(&end, &buflen, &dentry->d_name) != 0) ||

		    (prepend(&end, &buflen, "/", 1) != 0))

		spin_lock(&dentry->d_lock);

		error = prepend_name(&end, &buflen, &dentry->d_name);

		spin_unlock(&dentry->d_lock);

		if (error != 0 || prepend(&end, &buflen, "/", 1) != 0)

			goto Elong;



		retval = end;