Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6

[linux-2.6] / fs / nfs / pagelist.c

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d846d39a31efaca7ea08d78eef0a5aa1463dcbc3..c5bb51a29e8072198c57963f5c3c9dbf86ebc6ab 100644 (file)
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -11,6 +11,7 @@
 
 #include <linux/slab.h>
 #include <linux/file.h>
+#include <linux/sched.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/nfs3.h>
 #include <linux/nfs4.h>
@@ -20,8 +21,6 @@
 
 #include "internal.h"
 
-#define NFS_PARANOIA 1
-
 static struct kmem_cache *nfs_page_cachep;
 
 static inline struct nfs_page *
@@ -51,9 +50,7 @@ nfs_page_free(struct nfs_page *p)
  * @count: number of bytes to read/write
  *
  * The page must be locked by the caller. This makes sure we never
- * create two different requests for the same page, and avoids
- * a possible deadlock when we reach the hard limit on the number
- * of dirty pages.
+ * create two different requests for the same page.
  * User should ensure it is safe to sleep in this function.
  */
 struct nfs_page *
@@ -64,16 +61,12 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_page         *req;
 
-       /* Deal with hard limits.  */
        for (;;) {
                /* try to allocate the request struct */
                req = nfs_page_alloc();
                if (req != NULL)
                        break;
 
-               /* Try to free up at least one request in order to stay
-                * below the hard limit
-                */
                if (signalled() && (server->flags & NFS_MOUNT_INTR))
                        return ERR_PTR(-ERESTARTSYS);
                yield();
@@ -173,11 +166,6 @@ nfs_release_request(struct nfs_page *req)
        if (!atomic_dec_and_test(&req->wb_count))
                return;
 
-#ifdef NFS_PARANOIA
-       BUG_ON (!list_empty(&req->wb_list));
-       BUG_ON (NFS_WBACK_BUSY(req));
-#endif
-
        /* Release struct file or cached credential */
        nfs_clear_request(req);
        put_nfs_open_context(req->wb_context);
@@ -234,7 +222,7 @@ out:
 void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
                     struct inode *inode,
                     int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
-                    unsigned int bsize,
+                    size_t bsize,
                     int io_flags)
 {
        INIT_LIST_HEAD(&desc->pg_list);
@@ -367,6 +355,26 @@ void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
        nfs_pageio_doio(desc);
 }
 
+/**
+ * nfs_pageio_cond_complete - Conditional I/O completion
+ * @desc: pointer to io descriptor
+ * @index: page index
+ *
+ * It is important to ensure that processes don't try to take locks
+ * on non-contiguous ranges of pages as that might deadlock. This
+ * function should be called before attempting to wait on a locked
+ * nfs_page. It will complete the I/O if the page index 'index'
+ * is not contiguous with the existing list of pages in 'desc'.
+ */
+void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
+{
+       if (!list_empty(&desc->pg_list)) {
+               struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev);
+               if (index != prev->wb_index + 1)
+                       nfs_pageio_doio(desc);
+       }
+}
+
 #define NFS_SCAN_MAXENTRIES 16
 /**
  * nfs_scan_list - Scan a list for matching requests