Merge tag '5.4-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Seven cifs/smb3 fixes, including three for stable"

* tag '5.4-rc5-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs
  CIFS: Fix use after free of file info structures
  CIFS: Fix retry mid list corruption on reconnects
  cifs: Fix missed free operations
  CIFS: avoid using MID 0xFFFF
  cifs: clarify comment about timestamp granularity for old servers
  cifs: Handle -EINPROGRESS only when noblockcnt is set

9 files changed, 75 insertions, 37 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c049c7b3aa87..1a135d1b85bd 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -169,7 +169,13 @@ cifs_read_super(struct super_block *sb)
 	else
 		sb->s_maxbytes = MAX_NON_LFS;
 
-	/* Some very old servers like DOS and OS/2 used 2 second granularity */
+	/*
+	 * Some very old servers like DOS and OS/2 used 2 second granularity
+	 * (while all current servers use 100ns granularity - see MS-DTYP)
+	 * but 1 second is the maximum allowed granularity for the VFS
+	 * so for old servers set time granularity to 1 second while for
+	 * everything else (current servers) set it to 100ns.
+	 */
 	if ((tcon->ses->server->vals->protocol_id == SMB10_PROT_ID) &&
 	    ((tcon->ses->capabilities &
 	      tcon->ses->server->vals->cap_nt_find) == 0) &&
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 50dfd9049370..d78bfcc19156 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1391,6 +1391,11 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
 struct cifsInodeInfo {
 	bool can_cache_brlcks;
 	struct list_head llist;	/* locks helb by this inode */
+	/*
+	 * NOTE: Some code paths call down_read(lock_sem) twice, so
+	 * we must always use use cifs_down_write() instead of down_write()
+	 * for this semaphore to avoid deadlocks.
+	 */
 	struct rw_semaphore lock_sem;	/* protect the fields above */
 	/* BB add in lists for dirty pages i.e. write caching info for oplock */
 	struct list_head openFileList;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index e53e9f62b87b..fe597d3d5208 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -170,6 +170,7 @@ extern int cifs_unlock_range(struct cifsFileInfo *cfile,
 			     struct file_lock *flock, const unsigned int xid);
 extern int cifs_push_mandatory_locks(struct cifsFileInfo *cfile);
 
+extern void cifs_down_write(struct rw_semaphore *sem);
 extern struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid,
 					      struct file *file,
 					      struct tcon_link *tlink,
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a64dfa95a925..ccaa8bad336f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -564,9 +564,11 @@ cifs_reconnect(struct TCP_Server_Info *server)
 	spin_lock(&GlobalMid_Lock);
 	list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 		mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
+		kref_get(&mid_entry->refcount);
 		if (mid_entry->mid_state == MID_REQUEST_SUBMITTED)
 			mid_entry->mid_state = MID_RETRY_NEEDED;
 		list_move(&mid_entry->qhead, &retry_list);
+		mid_entry->mid_flags |= MID_DELETED;
 	}
 	spin_unlock(&GlobalMid_Lock);
 	mutex_unlock(&server->srv_mutex);
@@ -576,6 +578,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 		list_del_init(&mid_entry->qhead);
 		mid_entry->callback(mid_entry);
+		cifs_mid_q_entry_release(mid_entry);
 	}
 
 	if (cifs_rdma_enabled(server)) {
@@ -895,8 +898,10 @@ dequeue_mid(struct mid_q_entry *mid, bool malformed)
 	if (mid->mid_flags & MID_DELETED)
 		printk_once(KERN_WARNING
 			    "trying to dequeue a deleted mid\n");
-	else
+	else {
 		list_del_init(&mid->qhead);
+		mid->mid_flags |= MID_DELETED;
+	}
 	spin_unlock(&GlobalMid_Lock);
 }
 
@@ -966,8 +971,10 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
 		list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 			mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 			cifs_dbg(FYI, "Clearing mid 0x%llx\n", mid_entry->mid);
+			kref_get(&mid_entry->refcount);
 			mid_entry->mid_state = MID_SHUTDOWN;
 			list_move(&mid_entry->qhead, &dispose_list);
+			mid_entry->mid_flags |= MID_DELETED;
 		}
 		spin_unlock(&GlobalMid_Lock);
 
@@ -977,6 +984,7 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
 			cifs_dbg(FYI, "Callback mid 0x%llx\n", mid_entry->mid);
 			list_del_init(&mid_entry->qhead);
 			mid_entry->callback(mid_entry);
+			cifs_mid_q_entry_release(mid_entry);
 		}
 		/* 1/8th of sec is more than enough time for them to exit */
 		msleep(125);
@@ -3882,8 +3890,12 @@ generic_ip_connect(struct TCP_Server_Info *server)
 
 	rc = socket->ops->connect(socket, saddr, slen,
 				  server->noblockcnt ? O_NONBLOCK : 0);
-
-	if (rc == -EINPROGRESS)
+	/*
+	 * When mounting SMB root file systems, we do not want to block in
+	 * connect. Otherwise bail out and then let cifs_reconnect() perform
+	 * reconnect failover - if possible.
+	 */
+	if (server->noblockcnt && rc == -EINPROGRESS)
 		rc = 0;
 	if (rc < 0) {
 		cifs_dbg(FYI, "Error %d connecting to server\n", rc);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5ad15de2bb4f..fa7b0fa72bb3 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -281,6 +281,13 @@ cifs_has_mand_locks(struct cifsInodeInfo *cinode)
 	return has_locks;
 }
 
+void
+cifs_down_write(struct rw_semaphore *sem)
+{
+	while (!down_write_trylock(sem))
+		msleep(10);
+}
+
 struct cifsFileInfo *
 cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 		  struct tcon_link *tlink, __u32 oplock)
@@ -306,7 +313,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 	INIT_LIST_HEAD(&fdlocks->locks);
 	fdlocks->cfile = cfile;
 	cfile->llist = fdlocks;
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 	list_add(&fdlocks->llist, &cinode->llist);
 	up_write(&cinode->lock_sem);
 
@@ -405,10 +412,11 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
 	bool oplock_break_cancelled;
 
 	spin_lock(&tcon->open_file_lock);
-
+	spin_lock(&cifsi->open_file_lock);
 	spin_lock(&cifs_file->file_info_lock);
 	if (--cifs_file->count > 0) {
 		spin_unlock(&cifs_file->file_info_lock);
+		spin_unlock(&cifsi->open_file_lock);
 		spin_unlock(&tcon->open_file_lock);
 		return;
 	}
@@ -421,9 +429,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
 	cifs_add_pending_open_locked(&fid, cifs_file->tlink, &open);
 
 	/* remove it from the lists */
-	spin_lock(&cifsi->open_file_lock);
 	list_del(&cifs_file->flist);
-	spin_unlock(&cifsi->open_file_lock);
 	list_del(&cifs_file->tlist);
 	atomic_dec(&tcon->num_local_opens);
 
@@ -440,6 +446,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
 		cifs_set_oplock_level(cifsi, 0);
 	}
 
+	spin_unlock(&cifsi->open_file_lock);
 	spin_unlock(&tcon->open_file_lock);
 
 	oplock_break_cancelled = wait_oplock_handler ?
@@ -464,7 +471,7 @@ void _cifsFileInfo_put(struct cifsFileInfo *cifs_file, bool wait_oplock_handler)
 	 * Delete any outstanding lock records. We'll lose them when the file
 	 * is closed anyway.
 	 */
-	down_write(&cifsi->lock_sem);
+	cifs_down_write(&cifsi->lock_sem);
 	list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
 		list_del(&li->llist);
 		cifs_del_lock_waiters(li);
@@ -1027,7 +1034,7 @@ static void
 cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
 {
 	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 	list_add_tail(&lock->llist, &cfile->llist->locks);
 	up_write(&cinode->lock_sem);
 }
@@ -1049,7 +1056,7 @@ cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
 
 try_again:
 	exist = false;
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 
 	exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
 					lock->type, lock->flags, &conf_lock,
@@ -1072,7 +1079,7 @@ try_again:
 					(lock->blist.next == &lock->blist));
 		if (!rc)
 			goto try_again;
-		down_write(&cinode->lock_sem);
+		cifs_down_write(&cinode->lock_sem);
 		list_del_init(&lock->blist);
 	}
 
@@ -1125,7 +1132,7 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
 		return rc;
 
 try_again:
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 	if (!cinode->can_cache_brlcks) {
 		up_write(&cinode->lock_sem);
 		return rc;
@@ -1331,7 +1338,7 @@ cifs_push_locks(struct cifsFileInfo *cfile)
 	int rc = 0;
 
 	/* we are going to update can_cache_brlcks here - need a write access */
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 	if (!cinode->can_cache_brlcks) {
 		up_write(&cinode->lock_sem);
 		return rc;
@@ -1522,7 +1529,7 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
 	if (!buf)
 		return -ENOMEM;
 
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 	for (i = 0; i < 2; i++) {
 		cur = buf;
 		num = 0;
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 5dcc95b38310..df9377828e2f 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2475,9 +2475,9 @@ cifs_setattr_nounix(struct dentry *direntry, struct iattr *attrs)
 			rc = tcon->ses->server->ops->flush(xid, tcon, &wfile->fid);
 			cifsFileInfo_put(wfile);
 			if (rc)
-				return rc;
+				goto cifs_setattr_exit;
 		} else if (rc != -EBADF)
-			return rc;
+			goto cifs_setattr_exit;
 		else
 			rc = 0;
 	}
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index b7421a096319..514810694c0f 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -171,6 +171,9 @@ cifs_get_next_mid(struct TCP_Server_Info *server)
 	/* we do not want to loop forever */
 	last_mid = cur_mid;
 	cur_mid++;
+	/* avoid 0xFFFF MID */
+	if (cur_mid == 0xffff)
+		cur_mid++;
 
 	/*
 	 * This nested loop looks more expensive than it is.
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index e6a1fc72018f..8b0b512c5792 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -145,7 +145,7 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
 
 	cur = buf;
 
-	down_write(&cinode->lock_sem);
+	cifs_down_write(&cinode->lock_sem);
 	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
 		if (flock->fl_start > li->offset ||
 		    (flock->fl_start + length) <
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 308ad0f495e1..ca3de62688d6 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -86,22 +86,8 @@ AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
 
 static void _cifs_mid_q_entry_release(struct kref *refcount)
 {
-	struct mid_q_entry *mid = container_of(refcount, struct mid_q_entry,
-					       refcount);
-
-	mempool_free(mid, cifs_mid_poolp);
-}
-
-void cifs_mid_q_entry_release(struct mid_q_entry *midEntry)
-{
-	spin_lock(&GlobalMid_Lock);
-	kref_put(&midEntry->refcount, _cifs_mid_q_entry_release);
-	spin_unlock(&GlobalMid_Lock);
-}
-
-void
-DeleteMidQEntry(struct mid_q_entry *midEntry)
-{
+	struct mid_q_entry *midEntry =
+			container_of(refcount, struct mid_q_entry, refcount);
 #ifdef CONFIG_CIFS_STATS2
 	__le16 command = midEntry->server->vals->lock_cmd;
 	__u16 smb_cmd = le16_to_cpu(midEntry->command);
@@ -166,6 +152,19 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
 		}
 	}
 #endif
+
+	mempool_free(midEntry, cifs_mid_poolp);
+}
+
+void cifs_mid_q_entry_release(struct mid_q_entry *midEntry)
+{
+	spin_lock(&GlobalMid_Lock);
+	kref_put(&midEntry->refcount, _cifs_mid_q_entry_release);
+	spin_unlock(&GlobalMid_Lock);
+}
+
+void DeleteMidQEntry(struct mid_q_entry *midEntry)
+{
 	cifs_mid_q_entry_release(midEntry);
 }
 
@@ -173,8 +172,10 @@ void
 cifs_delete_mid(struct mid_q_entry *mid)
 {
 	spin_lock(&GlobalMid_Lock);
-	list_del_init(&mid->qhead);
-	mid->mid_flags |= MID_DELETED;
+	if (!(mid->mid_flags & MID_DELETED)) {
+		list_del_init(&mid->qhead);
+		mid->mid_flags |= MID_DELETED;
+	}
 	spin_unlock(&GlobalMid_Lock);
 
 	DeleteMidQEntry(mid);
@@ -872,7 +873,10 @@ cifs_sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 		rc = -EHOSTDOWN;
 		break;
 	default:
-		list_del_init(&mid->qhead);
+		if (!(mid->mid_flags & MID_DELETED)) {
+			list_del_init(&mid->qhead);
+			mid->mid_flags |= MID_DELETED;
+		}
 		cifs_server_dbg(VFS, "%s: invalid mid state mid=%llu state=%d\n",
 			 __func__, mid->mid, mid->mid_state);
 		rc = -EIO;