CIFS: Don't let read only caching for mandatory byte-range locked files
If we have mandatory byte-range locks on a file we can't cache reads
because pagereading may have conflicts with these locks on the server.
That's why we should allow level2 oplocks for files without mandatory
locks only.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 22c3725..8ea6ca5 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -238,6 +238,23 @@
return rc;
}
+static bool
+cifs_has_mand_locks(struct cifsInodeInfo *cinode)
+{
+ struct cifs_fid_locks *cur;
+ bool has_locks = false;
+
+ down_read(&cinode->lock_sem);
+ list_for_each_entry(cur, &cinode->llist, llist) {
+ if (!list_empty(&cur->locks)) {
+ has_locks = true;
+ break;
+ }
+ }
+ up_read(&cinode->lock_sem);
+ return has_locks;
+}
+
struct cifsFileInfo *
cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
struct tcon_link *tlink, __u32 oplock)
@@ -248,6 +265,7 @@
struct cifsFileInfo *cfile;
struct cifs_fid_locks *fdlocks;
struct cifs_tcon *tcon = tlink_tcon(tlink);
+ struct TCP_Server_Info *server = tcon->ses->server;
cfile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
if (cfile == NULL)
@@ -276,12 +294,22 @@
INIT_WORK(&cfile->oplock_break, cifs_oplock_break);
mutex_init(&cfile->fh_mutex);
+ /*
+ * If the server returned a read oplock and we have mandatory brlocks,
+ * set oplock level to None.
+ */
+ if (oplock == server->vals->oplock_read &&
+ cifs_has_mand_locks(cinode)) {
+ cFYI(1, "Reset oplock val from read to None due to mand locks");
+ oplock = 0;
+ }
+
spin_lock(&cifs_file_list_lock);
- if (fid->pending_open->oplock != CIFS_OPLOCK_NO_CHANGE)
+ if (fid->pending_open->oplock != CIFS_OPLOCK_NO_CHANGE && oplock)
oplock = fid->pending_open->oplock;
list_del(&fid->pending_open->olist);
- tlink_tcon(tlink)->ses->server->ops->set_fid(cfile, fid, oplock);
+ server->ops->set_fid(cfile, fid, oplock);
list_add(&cfile->tlist, &tcon->openFileList);
/* if readable file instance put first in list*/
@@ -1422,6 +1450,7 @@
struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct TCP_Server_Info *server = tcon->ses->server;
+ struct inode *inode = cfile->dentry->d_inode;
if (posix_lck) {
int posix_lock_type;
@@ -1459,6 +1488,21 @@
if (!rc)
goto out;
+ /*
+ * Windows 7 server can delay breaking lease from read to None
+ * if we set a byte-range lock on a file - break it explicitly
+ * before sending the lock to the server to be sure the next
+ * read won't conflict with non-overlapted locks due to
+ * pagereading.
+ */
+ if (!CIFS_I(inode)->clientCanCacheAll &&
+ CIFS_I(inode)->clientCanCacheRead) {
+ cifs_invalidate_mapping(inode);
+ cFYI(1, "Set no oplock for inode=%p due to mand locks",
+ inode);
+ CIFS_I(inode)->clientCanCacheRead = false;
+ }
+
rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
type, 1, 0, wait_flag);
if (rc) {
@@ -3537,6 +3581,13 @@
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
int rc = 0;
+ if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead &&
+ cifs_has_mand_locks(cinode)) {
+ cFYI(1, "Reset oplock to None for inode=%p due to mand locks",
+ inode);
+ cinode->clientCanCacheRead = false;
+ }
+
if (inode && S_ISREG(inode->i_mode)) {
if (cinode->clientCanCacheRead)
break_lease(inode, O_RDONLY);