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Commit 274f5b04 authored by Al Viro's avatar Al Viro
Browse files

dcache_{readdir,dir_lseek}(): don't bother with nested ->d_lock 



Make sure that directory is locked shared in dcache_dir_lseek();
for dcache_readdir() it's already tru, and that's enough to make
simple_positive() stable.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent e7d6ef97

fs/libfs.c

+3 −9
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) 
			struct dentry *cursor = file->private_data;

			loff_t n = file->f_pos - 2;



			inode_lock_shared(dentry->d_inode);

			spin_lock(&dentry->d_lock);

			/* d_lock not required for cursor */

			list_del(&cursor->d_child);
@@ -110,14 +111,13 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) 
			while (n && p != &dentry->d_subdirs) {

				struct dentry *next;

				next = list_entry(p, struct dentry, d_child);

				spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);

				if (simple_positive(next))

					n--;

				spin_unlock(&next->d_lock);

				p = p->next;

			}

			list_add_tail(&cursor->d_child, p);

			spin_unlock(&dentry->d_lock);

			inode_unlock_shared(dentry->d_inode);

		}

	}

	return offset;
@@ -150,22 +150,16 @@ int dcache_readdir(struct file *file, struct dir_context *ctx) 


	for (p = q->next; p != &dentry->d_subdirs; p = p->next) {

		struct dentry *next = list_entry(p, struct dentry, d_child);

		spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);

		if (!simple_positive(next)) {

			spin_unlock(&next->d_lock);

		if (!simple_positive(next))

			continue;

		}



		spin_unlock(&next->d_lock);

		spin_unlock(&dentry->d_lock);

		if (!dir_emit(ctx, next->d_name.name, next->d_name.len,

			      d_inode(next)->i_ino, dt_type(d_inode(next))))

			return 0;

		spin_lock(&dentry->d_lock);

		spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);

		/* next is still alive */

		list_move(q, p);

		spin_unlock(&next->d_lock);

		p = q;

		ctx->pos++;

	}