Commit 27d41fed authored by Chuck Lever's avatar Chuck Lever Committed by Yongjian Sun
Browse files

Revert "libfs: Add simple_offset_empty()" 

mainline inclusion
from mainline-v6.12-rc3
commit d7bde4f27ceef3dc6d72010a20d4da23db835a32
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBLWT7
CVE: CVE-2024-57952

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d7bde4f27ceef3dc6d72010a20d4da23db835a32



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

simple_empty() and simple_offset_empty() perform the same task.
The latter's use as a canary to find bugs has not found any new
issues. A subsequent patch will remove the use of the mtree for
iterating directory contents, so revert back to using a similar
mechanism for determining whether a directory is indeed empty.

Only one such mechanism is ever needed.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20241228175522.1854234-3-cel@kernel.org


Reviewed-by: default avatarYang Erkun <yangerkun@huawei.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarYongjian Sun <sunyongjian1@huawei.com>
parent a8fb4204

fs/libfs.c

+0 −32
Original line number Diff line number Diff line
@@ -311,38 +311,6 @@ void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry) 
	offset_set(dentry, 0);

}



/**

 * simple_offset_empty - Check if a dentry can be unlinked

 * @dentry: dentry to be tested

 *

 * Returns 0 if @dentry is a non-empty directory; otherwise returns 1.

 */

int simple_offset_empty(struct dentry *dentry)

{

	struct inode *inode = d_inode(dentry);

	struct offset_ctx *octx;

	struct dentry *child;

	unsigned long index;

	int ret = 1;



	if (!inode || !S_ISDIR(inode->i_mode))

		return ret;



	index = DIR_OFFSET_MIN;

	octx = inode->i_op->get_offset_ctx(inode);

	mt_for_each(&octx->mt, child, index, LONG_MAX) {

		spin_lock(&child->d_lock);

		if (simple_positive(child)) {

			spin_unlock(&child->d_lock);

			ret = 0;

			break;

		}

		spin_unlock(&child->d_lock);

	}



	return ret;

}



/**

 * simple_offset_rename - handle directory offsets for rename

 * @old_dir: parent directory of source entry

include/linux/fs.h

+0 −1
Original line number Diff line number Diff line
@@ -3286,7 +3286,6 @@ struct offset_ctx { 
void simple_offset_init(struct offset_ctx *octx);

int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry);

void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry);

int simple_offset_empty(struct dentry *dentry);

int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,

			 struct inode *new_dir, struct dentry *new_dentry);

int simple_offset_rename_exchange(struct inode *old_dir,

mm/shmem.c

+2 −2
Original line number Diff line number Diff line
@@ -3709,7 +3709,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) 


static int shmem_rmdir(struct inode *dir, struct dentry *dentry)

{

	if (!simple_offset_empty(dentry))

	if (!simple_empty(dentry))

		return -ENOTEMPTY;



	drop_nlink(d_inode(dentry));
@@ -3766,7 +3766,7 @@ static int shmem_rename2(struct mnt_idmap *idmap, 
		return simple_offset_rename_exchange(old_dir, old_dentry,

						     new_dir, new_dentry);



	if (!simple_offset_empty(new_dentry))

	if (!simple_empty(new_dentry))

		return -ENOTEMPTY;



	if (flags & RENAME_WHITEOUT) {