From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
Anton Vorontsov <anton@enomsg.org>,
Colin Cross <ccross@android.com>, Tony Luck <tony.luck@intel.com>,
Luis Henriques <lhenriques@suse.com>
Subject: [PATCH 07/10] pstore: Refactor pstorefs record list removal
Date: Wed, 6 May 2020 08:21:11 -0700 [thread overview]
Message-ID: <20200506152114.50375-8-keescook@chromium.org> (raw)
In-Reply-To: <20200506152114.50375-1-keescook@chromium.org>
The "unlink" handling should perform list removal (which can also make
sure records don't get double-erased), and the "evict" handling should
be responsible only for memory freeing.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/pstore/inode.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 92ebcc75434f..5f08b21b7a46 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -177,10 +177,21 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
{
struct pstore_private *p = d_inode(dentry)->i_private;
struct pstore_record *record = p->record;
+ int rc = 0;
if (!record->psi->erase)
return -EPERM;
+ /* Make sure we can't race while removing this file. */
+ mutex_lock(&records_list_lock);
+ if (!list_empty(&p->list))
+ list_del_init(&p->list);
+ else
+ rc = -ENOENT;
+ mutex_unlock(&records_list_lock);
+ if (rc)
+ return rc;
+
mutex_lock(&record->psi->read_mutex);
record->psi->erase(record);
mutex_unlock(&record->psi->read_mutex);
@@ -193,12 +204,7 @@ static void pstore_evict_inode(struct inode *inode)
struct pstore_private *p = inode->i_private;
clear_inode(inode);
- if (p) {
- mutex_lock(&records_list_lock);
- list_del(&p->list);
- mutex_unlock(&records_list_lock);
- free_pstore_private(p);
- }
+ free_pstore_private(p);
}
static const struct inode_operations pstore_dir_inode_operations = {
@@ -417,6 +423,7 @@ static void pstore_kill_sb(struct super_block *sb)
{
kill_litter_super(sb);
pstore_sb = NULL;
+ INIT_LIST_HEAD(&records_list);
}
static struct file_system_type pstore_fs_type = {
--
2.20.1
next prev parent reply other threads:[~2020-05-06 15:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-06 15:21 [PATCH 00/10] pstore: Remove filesystem records when backend is unregistered Kees Cook
2020-05-06 15:21 ` [PATCH 01/10] pstore: Drop useless try_module_get() for backend Kees Cook
2020-05-06 15:21 ` [PATCH 02/10] pstore: Rename "pstore_lock" to "psinfo_lock" Kees Cook
2020-05-06 15:21 ` [PATCH 03/10] pstore: Convert "psinfo" locking to mutex Kees Cook
2020-05-06 15:21 ` [PATCH 04/10] pstore: Rename "allpstore" to "records_list" Kees Cook
2020-05-06 15:21 ` [PATCH 05/10] pstore: Convert "records_list" locking to mutex Kees Cook
2020-05-06 15:21 ` [PATCH 06/10] pstore: Add proper unregister lock checking Kees Cook
2020-05-06 15:21 ` Kees Cook [this message]
2020-05-06 15:21 ` [PATCH 08/10] pstore: Add locking around superblock changes Kees Cook
2020-05-06 15:21 ` [PATCH 09/10] pstore: Do not leave timer disabled for next backend Kees Cook
2020-05-06 15:21 ` [PATCH 10/10] pstore: Remove filesystem records when backend is unregistered Kees Cook
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