From 9e992755be8f2d458a0bcbefd19e493483c1dba2 Mon Sep 17 00:00:00 2001 From: Rohith Surabattula Date: Mon, 9 Aug 2021 09:32:46 +0000 Subject: [PATCH] cifs: Call close synchronously during unlink/rename/lease break. During unlink/rename/lease break, deferred work for close is scheduled immediately but in an asynchronous manner which might lead to race with actual(unlink/rename) commands. This change will schedule close synchronously which will avoid the race conditions with other commands. Signed-off-by: Rohith Surabattula Reviewed-by: Shyam Prasad N Cc: stable@vger.kernel.org # 5.13 Signed-off-by: Steve French --- fs/cifs/cifsglob.h | 5 +++++ fs/cifs/file.c | 35 +++++++++++++++++------------------ fs/cifs/misc.c | 46 ++++++++++++++++++++++++++++++++++------------ 3 files changed, 56 insertions(+), 30 deletions(-) diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index c0bfc2f01030..c6a9542ca281 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1611,6 +1611,11 @@ struct dfs_info3_param { int ttl; }; +struct file_list { + struct list_head list; + struct cifsFileInfo *cfile; +}; + /* * common struct for holding inode info when searching for or updating an * inode with new info diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 0a72840a88f1..bb98fbdd22a9 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -4847,6 +4847,22 @@ void cifs_oplock_break(struct work_struct *work) cifs_dbg(VFS, "Push locks rc = %d\n", rc); oplock_break_ack: + /* + * When oplock break is received and there are no active + * file handles but cached, then schedule deferred close immediately. + * So, new open will not use cached handle. + */ + spin_lock(&CIFS_I(inode)->deferred_lock); + is_deferred = cifs_is_deferred_close(cfile, &dclose); + spin_unlock(&CIFS_I(inode)->deferred_lock); + if (is_deferred && + cfile->deferred_close_scheduled && + delayed_work_pending(&cfile->deferred)) { + if (cancel_delayed_work(&cfile->deferred)) { + _cifsFileInfo_put(cfile, false, false); + goto oplock_break_done; + } + } /* * releasing stale oplock after recent reconnect of smb session using * a now incorrect file handle is not a data integrity issue but do @@ -4858,24 +4874,7 @@ oplock_break_ack: cinode); cifs_dbg(FYI, "Oplock release rc = %d\n", rc); } - /* - * When oplock break is received and there are no active - * file handles but cached, then schedule deferred close immediately. - * So, new open will not use cached handle. - */ - spin_lock(&CIFS_I(inode)->deferred_lock); - is_deferred = cifs_is_deferred_close(cfile, &dclose); - if (is_deferred && - cfile->deferred_close_scheduled && - delayed_work_pending(&cfile->deferred)) { - /* - * If there is no pending work, mod_delayed_work queues new work. - * So, Increase the ref count to avoid use-after-free. - */ - if (!mod_delayed_work(deferredclose_wq, &cfile->deferred, 0)) - cifsFileInfo_get(cfile); - } - spin_unlock(&CIFS_I(inode)->deferred_lock); +oplock_break_done: _cifsFileInfo_put(cfile, false /* do not wait for ourself */, false); cifs_done_oplock_break(cinode); } diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index cdb1ec1461de..9469f1cf0b46 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -723,20 +723,32 @@ void cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode) { struct cifsFileInfo *cfile = NULL; + struct file_list *tmp_list, *tmp_next_list; + struct list_head file_head; if (cifs_inode == NULL) return; + INIT_LIST_HEAD(&file_head); + spin_lock(&cifs_inode->open_file_lock); list_for_each_entry(cfile, &cifs_inode->openFileList, flist) { if (delayed_work_pending(&cfile->deferred)) { - /* - * If there is no pending work, mod_delayed_work queues new work. - * So, Increase the ref count to avoid use-after-free. - */ - if (!mod_delayed_work(deferredclose_wq, &cfile->deferred, 0)) - cifsFileInfo_get(cfile); + if (cancel_delayed_work(&cfile->deferred)) { + tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC); + if (tmp_list == NULL) + continue; + tmp_list->cfile = cfile; + list_add_tail(&tmp_list->list, &file_head); + } } } + spin_unlock(&cifs_inode->open_file_lock); + + list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) { + _cifsFileInfo_put(tmp_list->cfile, true, false); + list_del(&tmp_list->list); + kfree(tmp_list); + } } void @@ -744,20 +756,30 @@ cifs_close_all_deferred_files(struct cifs_tcon *tcon) { struct cifsFileInfo *cfile; struct list_head *tmp; + struct file_list *tmp_list, *tmp_next_list; + struct list_head file_head; + INIT_LIST_HEAD(&file_head); spin_lock(&tcon->open_file_lock); list_for_each(tmp, &tcon->openFileList) { cfile = list_entry(tmp, struct cifsFileInfo, tlist); if (delayed_work_pending(&cfile->deferred)) { - /* - * If there is no pending work, mod_delayed_work queues new work. - * So, Increase the ref count to avoid use-after-free. - */ - if (!mod_delayed_work(deferredclose_wq, &cfile->deferred, 0)) - cifsFileInfo_get(cfile); + if (cancel_delayed_work(&cfile->deferred)) { + tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC); + if (tmp_list == NULL) + continue; + tmp_list->cfile = cfile; + list_add_tail(&tmp_list->list, &file_head); + } } } spin_unlock(&tcon->open_file_lock); + + list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) { + _cifsFileInfo_put(tmp_list->cfile, true, false); + list_del(&tmp_list->list); + kfree(tmp_list); + } } /* parses DFS refferal V3 structure