Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "A set of 5 small cifs fixes"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cif: fix dead code
  cifs: fix error handling cifs_user_readv
  fs: cifs: remove unused variable.
  Return correct error on query of xattr on file with empty xattrs
  cifs: Wait for writebacks to complete before attempting write.

10 files changed, 169 insertions, 13 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index df9c9141c09..5be1f997ecd 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -253,6 +253,11 @@ cifs_alloc_inode(struct super_block *sb)
 	cifs_set_oplock_level(cifs_inode, 0);
 	cifs_inode->delete_pending = false;
 	cifs_inode->invalid_mapping = false;
+	clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cifs_inode->flags);
+	clear_bit(CIFS_INODE_PENDING_WRITERS, &cifs_inode->flags);
+	clear_bit(CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2, &cifs_inode->flags);
+	spin_lock_init(&cifs_inode->writers_lock);
+	cifs_inode->writers = 0;
 	cifs_inode->vfs_inode.i_blkbits = 14;  /* 2**14 = CIFS_MAX_MSGSIZE */
 	cifs_inode->server_eof = 0;
 	cifs_inode->uniqueid = 0;
@@ -732,19 +737,26 @@ static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 				   unsigned long nr_segs, loff_t pos)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
 	ssize_t written;
 	int rc;
 
+	written = cifs_get_writer(cinode);
+	if (written)
+		return written;
+
 	written = generic_file_aio_write(iocb, iov, nr_segs, pos);
 
 	if (CIFS_CACHE_WRITE(CIFS_I(inode)))
-		return written;
+		goto out;
 
 	rc = filemap_fdatawrite(inode->i_mapping);
 	if (rc)
 		cifs_dbg(FYI, "cifs_file_aio_write: %d rc on %p inode\n",
 			 rc, inode);
 
+out:
+	cifs_put_writer(cinode);
 	return written;
 }
 
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index c0f3718b77a..30f6e9251a4 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -228,6 +228,8 @@ struct smb_version_operations {
 	/* verify the message */
 	int (*check_message)(char *, unsigned int);
 	bool (*is_oplock_break)(char *, struct TCP_Server_Info *);
+	void (*downgrade_oplock)(struct TCP_Server_Info *,
+					struct cifsInodeInfo *, bool);
 	/* process transaction2 response */
 	bool (*check_trans2)(struct mid_q_entry *, struct TCP_Server_Info *,
 			     char *, int);
@@ -1113,6 +1115,12 @@ struct cifsInodeInfo {
 	unsigned int epoch;		/* used to track lease state changes */
 	bool delete_pending;		/* DELETE_ON_CLOSE is set */
 	bool invalid_mapping;		/* pagecache is invalid */
+	unsigned long flags;
+#define CIFS_INODE_PENDING_OPLOCK_BREAK   (0) /* oplock break in progress */
+#define CIFS_INODE_PENDING_WRITERS	  (1) /* Writes in progress */
+#define CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2 (2) /* Downgrade oplock to L2 */
+	spinlock_t writers_lock;
+	unsigned int writers;		/* Number of writers on this inode */
 	unsigned long time;		/* jiffies of last update of inode */
 	u64  server_eof;		/* current file size on server -- protected by i_lock */
 	u64  uniqueid;			/* server inode number */
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index acc4ee8ed07..ca7980a1e30 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -127,6 +127,9 @@ extern u64 cifs_UnixTimeToNT(struct timespec);
 extern struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time,
 				      int offset);
 extern void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock);
+extern int cifs_get_writer(struct cifsInodeInfo *cinode);
+extern void cifs_put_writer(struct cifsInodeInfo *cinode);
+extern void cifs_done_oplock_break(struct cifsInodeInfo *cinode);
 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);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index f3264bd7a83..6ce4e0954b9 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -6197,6 +6197,9 @@ QAllEAsRetry:
 	cifs_dbg(FYI, "ea length %d\n", list_len);
 	if (list_len <= 8) {
 		cifs_dbg(FYI, "empty EA list returned from server\n");
+		/* didn't find the named attribute */
+		if (ea_name)
+			rc = -ENODATA;
 		goto QAllEAsOut;
 	}
 
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8add25538a3..5ed03e0b8b4 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2599,7 +2599,7 @@ cifs_writev(struct kiocb *iocb, const struct iovec *iov,
 			ssize_t err;
 
 			err = generic_write_sync(file, iocb->ki_pos - rc, rc);
-			if (rc < 0)
+			if (err < 0)
 				rc = err;
 		}
 	} else {
@@ -2621,12 +2621,20 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
 	ssize_t written;
 
+	written = cifs_get_writer(cinode);
+	if (written)
+		return written;
+
 	if (CIFS_CACHE_WRITE(cinode)) {
 		if (cap_unix(tcon->ses) &&
 		(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability))
-		    && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
-			return generic_file_aio_write(iocb, iov, nr_segs, pos);
-		return cifs_writev(iocb, iov, nr_segs, pos);
+		  && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0)) {
+			written = generic_file_aio_write(
+					iocb, iov, nr_segs, pos);
+			goto out;
+		}
+		written = cifs_writev(iocb, iov, nr_segs, pos);
+		goto out;
 	}
 	/*
 	 * For non-oplocked files in strict cache mode we need to write the data
@@ -2646,6 +2654,8 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
 			 inode);
 		cinode->oplock = 0;
 	}
+out:
+	cifs_put_writer(cinode);
 	return written;
 }
 
@@ -2872,7 +2882,7 @@ ssize_t cifs_user_readv(struct kiocb *iocb, const struct iovec *iov,
 					    cifs_uncached_readv_complete);
 		if (!rdata) {
 			rc = -ENOMEM;
-			goto error;
+			break;
 		}
 
 		rc = cifs_read_allocate_pages(rdata, npages);
@@ -3621,6 +3631,13 @@ static int cifs_launder_page(struct page *page)
 	return rc;
 }
 
+static int
+cifs_pending_writers_wait(void *unused)
+{
+	schedule();
+	return 0;
+}
+
 void cifs_oplock_break(struct work_struct *work)
 {
 	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
@@ -3628,8 +3645,15 @@ void cifs_oplock_break(struct work_struct *work)
 	struct inode *inode = cfile->dentry->d_inode;
 	struct cifsInodeInfo *cinode = CIFS_I(inode);
 	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	struct TCP_Server_Info *server = tcon->ses->server;
 	int rc = 0;
 
+	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
+			cifs_pending_writers_wait, TASK_UNINTERRUPTIBLE);
+
+	server->ops->downgrade_oplock(server, cinode,
+		test_bit(CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2, &cinode->flags));
+
 	if (!CIFS_CACHE_WRITE(cinode) && CIFS_CACHE_READ(cinode) &&
 						cifs_has_mand_locks(cinode)) {
 		cifs_dbg(FYI, "Reset oplock to None for inode=%p due to mand locks\n",
@@ -3666,6 +3690,7 @@ void cifs_oplock_break(struct work_struct *work)
 							     cinode);
 		cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
 	}
+	cifs_done_oplock_break(cinode);
 }
 
 /*
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 2f9f3790679..3b0c62e622d 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -466,8 +466,22 @@ is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 				cifs_dbg(FYI, "file id match, oplock break\n");
 				pCifsInode = CIFS_I(netfile->dentry->d_inode);
 
-				cifs_set_oplock_level(pCifsInode,
-					pSMB->OplockLevel ? OPLOCK_READ : 0);
+				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
+					&pCifsInode->flags);
+
+				/*
+				 * Set flag if the server downgrades the oplock
+				 * to L2 else clear.
+				 */
+				if (pSMB->OplockLevel)
+					set_bit(
+					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
+					   &pCifsInode->flags);
+				else
+					clear_bit(
+					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
+					   &pCifsInode->flags);
+
 				queue_work(cifsiod_wq,
 					   &netfile->oplock_break);
 				netfile->oplock_break_cancelled = false;
@@ -551,6 +565,62 @@ void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 		cinode->oplock = 0;
 }
 
+static int
+cifs_oplock_break_wait(void *unused)
+{
+	schedule();
+	return signal_pending(current) ? -ERESTARTSYS : 0;
+}
+
+/*
+ * We wait for oplock breaks to be processed before we attempt to perform
+ * writes.
+ */
+int cifs_get_writer(struct cifsInodeInfo *cinode)
+{
+	int rc;
+
+start:
+	rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
+				   cifs_oplock_break_wait, TASK_KILLABLE);
+	if (rc)
+		return rc;
+
+	spin_lock(&cinode->writers_lock);
+	if (!cinode->writers)
+		set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+	cinode->writers++;
+	/* Check to see if we have started servicing an oplock break */
+	if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
+		cinode->writers--;
+		if (cinode->writers == 0) {
+			clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+			wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
+		}
+		spin_unlock(&cinode->writers_lock);
+		goto start;
+	}
+	spin_unlock(&cinode->writers_lock);
+	return 0;
+}
+
+void cifs_put_writer(struct cifsInodeInfo *cinode)
+{
+	spin_lock(&cinode->writers_lock);
+	cinode->writers--;
+	if (cinode->writers == 0) {
+		clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
+		wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
+	}
+	spin_unlock(&cinode->writers_lock);
+}
+
+void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
+{
+	clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
+	wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
+}
+
 bool
 backup_cred(struct cifs_sb_info *cifs_sb)
 {
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index 526fb89f923..d1fdfa84870 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -372,6 +372,16 @@ coalesce_t2(char *second_buf, struct smb_hdr *target_hdr)
 	return 0;
 }
 
+static void
+cifs_downgrade_oplock(struct TCP_Server_Info *server,
+			struct cifsInodeInfo *cinode, bool set_level2)
+{
+	if (set_level2)
+		cifs_set_oplock_level(cinode, OPLOCK_READ);
+	else
+		cifs_set_oplock_level(cinode, 0);
+}
+
 static bool
 cifs_check_trans2(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 		  char *buf, int malformed)
@@ -1019,6 +1029,7 @@ struct smb_version_operations smb1_operations = {
 	.clear_stats = cifs_clear_stats,
 	.print_stats = cifs_print_stats,
 	.is_oplock_break = is_valid_oplock_break,
+	.downgrade_oplock = cifs_downgrade_oplock,
 	.check_trans2 = cifs_check_trans2,
 	.need_neg = cifs_need_neg,
 	.negotiate = cifs_negotiate,
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index fb3966265b6..b8021fde987 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -575,9 +575,21 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 				else
 					cfile->oplock_break_cancelled = false;
 
-				server->ops->set_oplock_level(cinode,
-				  rsp->OplockLevel ? SMB2_OPLOCK_LEVEL_II : 0,
-				  0, NULL);
+				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
+					&cinode->flags);
+
+				/*
+				 * Set flag if the server downgrades the oplock
+				 * to L2 else clear.
+				 */
+				if (rsp->OplockLevel)
+					set_bit(
+					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
+					   &cinode->flags);
+				else
+					clear_bit(
+					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
+					   &cinode->flags);
 
 				queue_work(cifsiod_wq, &cfile->oplock_break);
 
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 192f51a12cf..35ddc3ed119 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -905,6 +905,17 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 }
 
 static void
+smb2_downgrade_oplock(struct TCP_Server_Info *server,
+			struct cifsInodeInfo *cinode, bool set_level2)
+{
+	if (set_level2)
+		server->ops->set_oplock_level(cinode, SMB2_OPLOCK_LEVEL_II,
+						0, NULL);
+	else
+		server->ops->set_oplock_level(cinode, 0, 0, NULL);
+}
+
+static void
 smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
 		      unsigned int epoch, bool *purge_cache)
 {
@@ -1110,6 +1121,7 @@ struct smb_version_operations smb20_operations = {
 	.clear_stats = smb2_clear_stats,
 	.print_stats = smb2_print_stats,
 	.is_oplock_break = smb2_is_valid_oplock_break,
+	.downgrade_oplock = smb2_downgrade_oplock,
 	.need_neg = smb2_need_neg,
 	.negotiate = smb2_negotiate,
 	.negotiate_wsize = smb2_negotiate_wsize,
@@ -1184,6 +1196,7 @@ struct smb_version_operations smb21_operations = {
 	.clear_stats = smb2_clear_stats,
 	.print_stats = smb2_print_stats,
 	.is_oplock_break = smb2_is_valid_oplock_break,
+	.downgrade_oplock = smb2_downgrade_oplock,
 	.need_neg = smb2_need_neg,
 	.negotiate = smb2_negotiate,
 	.negotiate_wsize = smb2_negotiate_wsize,
@@ -1259,6 +1272,7 @@ struct smb_version_operations smb30_operations = {
 	.print_stats = smb2_print_stats,
 	.dump_share_caps = smb2_dump_share_caps,
 	.is_oplock_break = smb2_is_valid_oplock_break,
+	.downgrade_oplock = smb2_downgrade_oplock,
 	.need_neg = smb2_need_neg,
 	.negotiate = smb2_negotiate,
 	.negotiate_wsize = smb2_negotiate_wsize,
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 86034470106..3802f8c94ac 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1352,7 +1352,6 @@ SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
 		     u64 persistent_fid, u64 volatile_fid)
 {
 	int rc;
-	char *res_key = NULL;
 	struct  compress_ioctl fsctl_input;
 	char *ret_data = NULL;
 
@@ -1365,7 +1364,6 @@ SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
 			2 /* in data len */, &ret_data /* out data */, NULL);
 
 	cifs_dbg(FYI, "set compression rc %d\n", rc);
-	kfree(res_key);
 
 	return rc;
 }