From: Pavel Shilovsky pshilov@microsoft.com
commit fa9c2362497fbd64788063288dc4e74daf977ebb upstream.
Even when mounting modern protocol version the server may be configured without supporting SMB2.1 leases and the client uses SMB2 oplock to optimize IO performance through local caching.
However there is a problem in oplock break handling that leads to missing a break notification on the client who has a file opened. It latter causes big latencies to other clients that are trying to open the same file.
The problem reproduces when there are multiple shares from the same server mounted on the client. The processing code tries to match persistent and volatile file ids from the break notification with an open file but it skips all share besides the first one. Fix this by looking up in all shares belonging to the server that issued the oplock break.
Cc: Stable stable@vger.kernel.org Signed-off-by: Pavel Shilovsky pshilov@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/smb2misc.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
--- a/fs/cifs/smb2misc.c +++ b/fs/cifs/smb2misc.c @@ -673,10 +673,10 @@ smb2_is_valid_oplock_break(char *buffer, spin_lock(&cifs_tcp_ses_lock); list_for_each(tmp, &server->smb_ses_list) { ses = list_entry(tmp, struct cifs_ses, smb_ses_list); + list_for_each(tmp1, &ses->tcon_list) { tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
- cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks); spin_lock(&tcon->open_file_lock); list_for_each(tmp2, &tcon->openFileList) { cfile = list_entry(tmp2, struct cifsFileInfo, @@ -688,6 +688,8 @@ smb2_is_valid_oplock_break(char *buffer, continue;
cifs_dbg(FYI, "file id match, oplock break\n"); + cifs_stats_inc( + &tcon->stats.cifs_stats.num_oplock_brks); cinode = CIFS_I(d_inode(cfile->dentry)); spin_lock(&cfile->file_info_lock); if (!CIFS_CACHE_WRITE(cinode) && @@ -720,9 +722,6 @@ smb2_is_valid_oplock_break(char *buffer, return true; } spin_unlock(&tcon->open_file_lock); - spin_unlock(&cifs_tcp_ses_lock); - cifs_dbg(FYI, "No matching file for oplock break\n"); - return true; } } spin_unlock(&cifs_tcp_ses_lock);