NFS: Replace vfsmount and dentry in nfs_open_context with struct path
[linux-2.6.git] / fs / nfs / pagelist.c
index 7017eb0..f8a4ba5 100644 (file)
 
 #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>
 #include <linux/nfs_page.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_mount.h>
-#include <linux/writeback.h>
 
-#define NFS_PARANOIA 1
+#include "internal.h"
 
 static struct kmem_cache *nfs_page_cachep;
 
@@ -50,9 +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 *
@@ -63,16 +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();
@@ -120,7 +114,7 @@ void nfs_unlock_request(struct nfs_page *req)
  */
 int nfs_set_page_writeback_locked(struct nfs_page *req)
 {
-       struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
+       struct nfs_inode *nfsi = NFS_I(req->wb_context->path.dentry->d_inode);
 
        if (!nfs_lock_request(req))
                return 0;
@@ -133,7 +127,7 @@ int nfs_set_page_writeback_locked(struct nfs_page *req)
  */
 void nfs_clear_page_writeback(struct nfs_page *req)
 {
-       struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
+       struct nfs_inode *nfsi = NFS_I(req->wb_context->path.dentry->d_inode);
 
        if (req->wb_page != NULL) {
                spin_lock(&nfsi->req_lock);
@@ -172,11 +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);
@@ -204,7 +193,7 @@ static int nfs_wait_bit_interruptible(void *word)
 int
 nfs_wait_on_request(struct nfs_page *req)
 {
-        struct rpc_clnt        *clnt = NFS_CLIENT(req->wb_context->dentry->d_inode);
+       struct rpc_clnt *clnt = NFS_CLIENT(req->wb_context->path.dentry->d_inode);
        sigset_t oldmask;
        int ret = 0;
 
@@ -225,14 +214,26 @@ out:
 /**
  * nfs_pageio_init - initialise a page io descriptor
  * @desc: pointer to descriptor
- * @iosize: io block size
+ * @inode: pointer to inode
+ * @doio: pointer to io function
+ * @bsize: io block size
+ * @io_flags: extra parameters for the io function
  */
-void nfs_pageio_init(struct nfs_pageio_descriptor *desc, unsigned int bsize)
+void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
+                    struct inode *inode,
+                    int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
+                    size_t bsize,
+                    int io_flags)
 {
        INIT_LIST_HEAD(&desc->pg_list);
+       desc->pg_bytes_written = 0;
        desc->pg_count = 0;
        desc->pg_bsize = bsize;
        desc->pg_base = 0;
+       desc->pg_inode = inode;
+       desc->pg_doio = doio;
+       desc->pg_ioflags = io_flags;
+       desc->pg_error = 0;
 }
 
 /**
@@ -265,15 +266,15 @@ static int nfs_can_coalesce_requests(struct nfs_page *prev,
 }
 
 /**
- * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
+ * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
  * @desc: destination io descriptor
  * @req: request
  *
  * Returns true if the request 'req' was successfully coalesced into the
  * existing list of pages 'desc'.
  */
-static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
-                                 struct nfs_page *req)
+static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
+                                    struct nfs_page *req)
 {
        size_t newlen = req->wb_bytes;
 
@@ -287,8 +288,10 @@ static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
                 * since nfs_flush_multi and nfs_pagein_multi assume you
                 * can have only one struct nfs_page.
                 */
+               if (desc->pg_bsize < PAGE_SIZE)
+                       return 0;
                newlen += desc->pg_count;
-               if (desc->pg_base + newlen > desc->pg_bsize)
+               if (newlen > desc->pg_bsize)
                        return 0;
                prev = nfs_list_entry(desc->pg_list.prev);
                if (!nfs_can_coalesce_requests(prev, req))
@@ -301,98 +304,78 @@ static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
        return 1;
 }
 
-/**
- * nfs_pageio_add_list - Split coalesced requests out from a list.
- * @desc: destination io descriptor
- * @head: source list
- *
- * Moves a maximum of 'nmax' elements from one list to another.
- * The elements are checked to ensure that they form a contiguous set
- * of pages, and that the RPC credentials are the same.
+/*
+ * Helper for nfs_pageio_add_request and nfs_pageio_complete
  */
-void nfs_pageio_add_list(struct nfs_pageio_descriptor *desc,
-                        struct list_head *head)
+static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
 {
-       while (!list_empty(head)) {
-               struct nfs_page *req = nfs_list_entry(head->next);
-               if (!nfs_pageio_add_request(desc, req))
-                       break;
+       if (!list_empty(&desc->pg_list)) {
+               int error = desc->pg_doio(desc->pg_inode,
+                                         &desc->pg_list,
+                                         nfs_page_array_len(desc->pg_base,
+                                                            desc->pg_count),
+                                         desc->pg_count,
+                                         desc->pg_ioflags);
+               if (error < 0)
+                       desc->pg_error = error;
+               else
+                       desc->pg_bytes_written += desc->pg_count;
+       }
+       if (list_empty(&desc->pg_list)) {
+               desc->pg_count = 0;
+               desc->pg_base = 0;
        }
 }
 
-#define NFS_SCAN_MAXENTRIES 16
 /**
- * nfs_scan_dirty - Scan the radix tree for dirty requests
- * @mapping: pointer to address space
- * @wbc: writeback_control structure
- * @dst: Destination list
+ * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
+ * @desc: destination io descriptor
+ * @req: request
  *
- * Moves elements from one of the inode request lists.
- * If the number of requests is set to 0, the entire address_space
- * starting at index idx_start, is scanned.
- * The requests are *not* checked to ensure that they form a contiguous set.
- * You must be holding the inode's req_lock when calling this function
+ * Returns true if the request 'req' was successfully coalesced into the
+ * existing list of pages 'desc'.
  */
-long nfs_scan_dirty(struct address_space *mapping,
-                       struct writeback_control *wbc,
-                       struct list_head *dst)
+int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
+                          struct nfs_page *req)
 {
-       struct nfs_inode *nfsi = NFS_I(mapping->host);
-       struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
-       struct nfs_page *req;
-       pgoff_t idx_start, idx_end;
-       long res = 0;
-       int found, i;
-
-       if (nfsi->ndirty == 0)
-               return 0;
-       if (wbc->range_cyclic) {
-               idx_start = 0;
-               idx_end = ULONG_MAX;
-       } else if (wbc->range_end == 0) {
-               idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
-               idx_end = ULONG_MAX;
-       } else {
-               idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
-               idx_end = wbc->range_end >> PAGE_CACHE_SHIFT;
+       while (!nfs_pageio_do_add_request(desc, req)) {
+               nfs_pageio_doio(desc);
+               if (desc->pg_error < 0)
+                       return 0;
        }
+       return 1;
+}
 
-       for (;;) {
-               unsigned int toscan = NFS_SCAN_MAXENTRIES;
-
-               found = radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree,
-                               (void **)&pgvec[0], idx_start, toscan,
-                               NFS_PAGE_TAG_DIRTY);
-
-               /* Did we make progress? */
-               if (found <= 0)
-                       break;
-
-               for (i = 0; i < found; i++) {
-                       req = pgvec[i];
-                       if (!wbc->range_cyclic && req->wb_index > idx_end)
-                               goto out;
+/**
+ * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor
+ * @desc: pointer to io descriptor
+ */
+void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
+{
+       nfs_pageio_doio(desc);
+}
 
-                       /* Try to lock request and mark it for writeback */
-                       if (!nfs_set_page_writeback_locked(req))
-                               goto next;
-                       radix_tree_tag_clear(&nfsi->nfs_page_tree,
-                                       req->wb_index, NFS_PAGE_TAG_DIRTY);
-                       nfsi->ndirty--;
-                       nfs_list_remove_request(req);
-                       nfs_list_add_request(req, dst);
-                       res++;
-                       if (res == LONG_MAX)
-                               goto out;
-next:
-                       idx_start = req->wb_index + 1;
-               }
+/**
+ * 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);
        }
-out:
-       WARN_ON ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty));
-       return res;
 }
 
+#define NFS_SCAN_MAXENTRIES 16
 /**
  * nfs_scan_list - Scan a list for matching requests
  * @nfsi: NFS inode
@@ -408,12 +391,12 @@ out:
  * You must be holding the inode's req_lock when calling this function
  */
 int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head,
-               struct list_head *dst, unsigned long idx_start,
+               struct list_head *dst, pgoff_t idx_start,
                unsigned int npages)
 {
        struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
        struct nfs_page *req;
-       unsigned long idx_end;
+       pgoff_t idx_end;
        int found, i;
        int res;