1 files changed, 73 insertions, 47 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 3d518b9e8c18..06dfaacfea5d 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2310,16 +2310,16 @@ compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
 	    (new->mnt_cifs_flags & CIFS_MOUNT_MASK))
 		return 0;
 
-	if (old->rsize != new->rsize)
-		return 0;
-
 	/*
-	 * We want to share sb only if we don't specify wsize or specified wsize
-	 * is greater or equal than existing one.
+	 * We want to share sb only if we don't specify an r/wsize or
+	 * specified r/wsize is greater than or equal to existing one.
 	 */
 	if (new->wsize && new->wsize < old->wsize)
 		return 0;
 
+	if (new->rsize && new->rsize < old->rsize)
+		return 0;
+
 	if (old->mnt_uid != new->mnt_uid || old->mnt_gid != new->mnt_gid)
 		return 0;
 
@@ -2757,14 +2757,6 @@ void reset_cifs_unix_caps(int xid, struct cifs_tcon *tcon,
 					CIFS_MOUNT_POSIX_PATHS;
 		}
 
-		if (cifs_sb && (cifs_sb->rsize > 127 * 1024)) {
-			if ((cap & CIFS_UNIX_LARGE_READ_CAP) == 0) {
-				cifs_sb->rsize = 127 * 1024;
-				cFYI(DBG2, "larger reads not supported by srv");
-			}
-		}
-
-
 		cFYI(1, "Negotiate caps 0x%x", (int)cap);
 #ifdef CONFIG_CIFS_DEBUG2
 		if (cap & CIFS_UNIX_FCNTL_CAP)
@@ -2809,27 +2801,11 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 	spin_lock_init(&cifs_sb->tlink_tree_lock);
 	cifs_sb->tlink_tree = RB_ROOT;
 
-	if (pvolume_info->rsize > CIFSMaxBufSize) {
-		cERROR(1, "rsize %d too large, using MaxBufSize",
-			pvolume_info->rsize);
-		cifs_sb->rsize = CIFSMaxBufSize;
-	} else if ((pvolume_info->rsize) &&
-			(pvolume_info->rsize <= CIFSMaxBufSize))
-		cifs_sb->rsize = pvolume_info->rsize;
-	else /* default */
-		cifs_sb->rsize = CIFSMaxBufSize;
-
-	if (cifs_sb->rsize < 2048) {
-		cifs_sb->rsize = 2048;
-		/* Windows ME may prefer this */
-		cFYI(1, "readsize set to minimum: 2048");
-	}
-
 	/*
-	 * Temporarily set wsize for matching superblock. If we end up using
-	 * new sb then cifs_negotiate_wsize will later negotiate it downward
-	 * if needed.
+	 * Temporarily set r/wsize for matching superblock. If we end up using
+	 * new sb then client will later negotiate it downward if needed.
 	 */
+	cifs_sb->rsize = pvolume_info->rsize;
 	cifs_sb->wsize = pvolume_info->wsize;
 
 	cifs_sb->mnt_uid = pvolume_info->linux_uid;
@@ -2904,29 +2880,41 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 }
 
 /*
- * When the server supports very large writes via POSIX extensions, we can
- * allow up to 2^24-1, minus the size of a WRITE_AND_X header, not including
- * the RFC1001 length.
+ * When the server supports very large reads and writes via POSIX extensions,
+ * we can allow up to 2^24-1, minus the size of a READ/WRITE_AND_X header, not
+ * including the RFC1001 length.
  *
  * Note that this might make for "interesting" allocation problems during
  * writeback however as we have to allocate an array of pointers for the
  * pages. A 16M write means ~32kb page array with PAGE_CACHE_SIZE == 4096.
+ *
+ * For reads, there is a similar problem as we need to allocate an array
+ * of kvecs to handle the receive, though that should only need to be done
+ * once.
  */
 #define CIFS_MAX_WSIZE ((1<<24) - 1 - sizeof(WRITE_REQ) + 4)
+#define CIFS_MAX_RSIZE ((1<<24) - sizeof(READ_RSP) + 4)
 
 /*
- * When the server doesn't allow large posix writes, only allow a wsize of
- * 2^17-1 minus the size of the WRITE_AND_X header. That allows for a write up
- * to the maximum size described by RFC1002.
+ * When the server doesn't allow large posix writes, only allow a rsize/wsize
+ * of 2^17-1 minus the size of the call header. That allows for a read or
+ * write up to the maximum size described by RFC1002.
  */
 #define CIFS_MAX_RFC1002_WSIZE ((1<<17) - 1 - sizeof(WRITE_REQ) + 4)
+#define CIFS_MAX_RFC1002_RSIZE ((1<<17) - 1 - sizeof(READ_RSP) + 4)
 
 /*
  * The default wsize is 1M. find_get_pages seems to return a maximum of 256
  * pages in a single call. With PAGE_CACHE_SIZE == 4k, this means we can fill
  * a single wsize request with a single call.
  */
-#define CIFS_DEFAULT_WSIZE (1024 * 1024)
+#define CIFS_DEFAULT_IOSIZE (1024 * 1024)
+
+/*
+ * Windows only supports a max of 60k reads. Default to that when posix
+ * extensions aren't in force.
+ */
+#define CIFS_DEFAULT_NON_POSIX_RSIZE (60 * 1024)
 
 static unsigned int
 cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
@@ -2934,7 +2922,7 @@ cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
 	__u64 unix_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
 	struct TCP_Server_Info *server = tcon->ses->server;
 	unsigned int wsize = pvolume_info->wsize ? pvolume_info->wsize :
-				CIFS_DEFAULT_WSIZE;
+				CIFS_DEFAULT_IOSIZE;
 
 	/* can server support 24-bit write sizes? (via UNIX extensions) */
 	if (!tcon->unix_ext || !(unix_cap & CIFS_UNIX_LARGE_WRITE_CAP))
@@ -2957,6 +2945,50 @@ cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
 	return wsize;
 }
 
+static unsigned int
+cifs_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
+{
+	__u64 unix_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
+	struct TCP_Server_Info *server = tcon->ses->server;
+	unsigned int rsize, defsize;
+
+	/*
+	 * Set default value...
+	 *
+	 * HACK alert! Ancient servers have very small buffers. Even though
+	 * MS-CIFS indicates that servers are only limited by the client's
+	 * bufsize for reads, testing against win98se shows that it throws
+	 * INVALID_PARAMETER errors if you try to request too large a read.
+	 *
+	 * If the server advertises a MaxBufferSize of less than one page,
+	 * assume that it also can't satisfy reads larger than that either.
+	 *
+	 * FIXME: Is there a better heuristic for this?
+	 */
+	if (tcon->unix_ext && (unix_cap & CIFS_UNIX_LARGE_READ_CAP))
+		defsize = CIFS_DEFAULT_IOSIZE;
+	else if (server->capabilities & CAP_LARGE_READ_X)
+		defsize = CIFS_DEFAULT_NON_POSIX_RSIZE;
+	else if (server->maxBuf >= PAGE_CACHE_SIZE)
+		defsize = CIFSMaxBufSize;
+	else
+		defsize = server->maxBuf - sizeof(READ_RSP);
+
+	rsize = pvolume_info->rsize ? pvolume_info->rsize : defsize;
+
+	/*
+	 * no CAP_LARGE_READ_X? Then MS-CIFS states that we must limit this to
+	 * the client's MaxBufferSize.
+	 */
+	if (!(server->capabilities & CAP_LARGE_READ_X))
+		rsize = min_t(unsigned int, CIFSMaxBufSize, rsize);
+
+	/* hard limit of CIFS_MAX_RSIZE */
+	rsize = min_t(unsigned int, rsize, CIFS_MAX_RSIZE);
+
+	return rsize;
+}
+
 static int
 is_path_accessible(int xid, struct cifs_tcon *tcon,
 		   struct cifs_sb_info *cifs_sb, const char *full_path)
@@ -3234,14 +3266,8 @@ try_mount_again:
 		CIFSSMBQFSAttributeInfo(xid, tcon);
 	}
 
-	if ((tcon->unix_ext == 0) && (cifs_sb->rsize > (1024 * 127))) {
-		cifs_sb->rsize = 1024 * 127;
-		cFYI(DBG2, "no very large read support, rsize now 127K");
-	}
-	if (!(tcon->ses->capabilities & CAP_LARGE_READ_X))
-		cifs_sb->rsize = min(cifs_sb->rsize, CIFSMaxBufSize);
-
 	cifs_sb->wsize = cifs_negotiate_wsize(tcon, volume_info);
+	cifs_sb->rsize = cifs_negotiate_rsize(tcon, volume_info);
 
 remote_path_check:
 #ifdef CONFIG_CIFS_DFS_UPCALL