[Kernel] [PATCH OpenHarmony-4.19 24/49] pstore: Refactor pstorefs record list removal

From: Kees Cook <keescook(a)chromium.org> stable inclusion from stable-5.10 category: feature commit:7a0ad546847a23f92f5e227fa8e4578eaa3a8d0a issue: #I4919J -------------------------------- 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. Link: https://lore.kernel.org/lkml/20200506152114.50375-8-keescook@chromium.org/ Signed-off-by: Kees Cook <keescook(a)chromium.org> (cherry picked from commit 7a0ad546847a23f92f5e227fa8e4578eaa3a8d0a) Signed-off-by: roger <kongzhengrong(a)huawei.com> --- 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 d5760195a0ad..7bec953e2dbc 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -189,10 +189,21 @@ 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); @@ -205,12 +216,7 @@ 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 = { @@ -430,6 +436,7 @@ 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 = { -- 2.17.1