Clarify locking of cifs file and tcon structures and make more granular
Remove the global file_list_lock to simplify cifs/smb3 locking and
have spinlocks that more closely match the information they are
protecting.
Add new tcon->open_file_lock and file->file_info_lock spinlocks.
Locks continue to follow a heirachy,
cifs_socket --> cifs_ses --> cifs_tcon --> cifs_file
where global tcp_ses_lock still protects socket and cifs_ses, while the
the newer locks protect the lower level structure's information
(tcon and cifs_file respectively).
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <steve.french@primarydata.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 813fe13..c672915 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -120,6 +120,7 @@ tconInfoAlloc(void)
++ret_buf->tc_count;
INIT_LIST_HEAD(&ret_buf->openFileList);
INIT_LIST_HEAD(&ret_buf->tcon_list);
+ spin_lock_init(&ret_buf->open_file_lock);
#ifdef CONFIG_CIFS_STATS
spin_lock_init(&ret_buf->stat_lock);
#endif
@@ -465,7 +466,7 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
continue;
cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tcon->open_file_lock);
list_for_each(tmp2, &tcon->openFileList) {
netfile = list_entry(tmp2, struct cifsFileInfo,
tlist);
@@ -495,11 +496,11 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
&netfile->oplock_break);
netfile->oplock_break_cancelled = false;
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
return true;
}
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tcon->open_file_lock);
spin_unlock(&cifs_tcp_ses_lock);
cifs_dbg(FYI, "No matching file for oplock break\n");
return true;
@@ -613,9 +614,9 @@ backup_cred(struct cifs_sb_info *cifs_sb)
void
cifs_del_pending_open(struct cifs_pending_open *open)
{
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
list_del(&open->olist);
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
}
void
@@ -635,7 +636,7 @@ void
cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
struct cifs_pending_open *open)
{
- spin_lock(&cifs_file_list_lock);
+ spin_lock(&tlink_tcon(tlink)->open_file_lock);
cifs_add_pending_open_locked(fid, tlink, open);
- spin_unlock(&cifs_file_list_lock);
+ spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
}