NFS: Clean up nfs_scan_dirty()

Pass down struct writeback control.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 67 insertions, 63 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 829af323f288..e046c9b6a9dd 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -17,6 +17,7 @@
 #include <linux/nfs_page.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_mount.h>
+#include <linux/writeback.h>
 
 #define NFS_PARANOIA 1
 
@@ -268,11 +269,10 @@ nfs_coalesce_requests(struct list_head *head, struct list_head *dst,
 
 #define NFS_SCAN_MAXENTRIES 16
 /**
- * nfs_scan_lock_dirty - Scan the radix tree for dirty requests
- * @nfsi: NFS inode
+ * nfs_scan_dirty - Scan the radix tree for dirty requests
+ * @mapping: pointer to address space
+ * @wbc: writeback_control structure
  * @dst: Destination list
- * @idx_start: lower bound of page->index to scan
- * @npages: idx_start + npages sets the upper bound to scan.
  *
  * Moves elements from one of the inode request lists.
  * If the number of requests is set to 0, the entire address_space
@@ -280,46 +280,72 @@ nfs_coalesce_requests(struct list_head *head, struct list_head *dst,
  * 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
  */
-int
-nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
-              unsigned long idx_start, unsigned int npages)
+long nfs_scan_dirty(struct address_space *mapping,
+                        struct writeback_control *wbc,
+                        struct list_head *dst)
 {
+        struct nfs_inode *nfsi = NFS_I(mapping->host);
         struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
         struct nfs_page *req;
-        unsigned long idx_end;
+        pgoff_t idx_start, idx_end;
+        long count = wbc->nr_to_write;
+        long res = 0;
         int found, i;
-        int res;
 
-        res = 0;
-        if (npages == 0)
-                idx_end = ~0;
-        else
-                idx_end = idx_start + npages - 1;
+        if (nfsi->ndirty == 0 || count <= 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;
+        }
 
         for (;;) {
+                unsigned int toscan = NFS_SCAN_MAXENTRIES;
+
+                if (toscan > count)
+                        toscan = count;
                 found = radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree,
-                                (void **)&pgvec[0], idx_start, NFS_SCAN_MAXENTRIES,
+                                (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 (req->wb_index > idx_end)
+                        if (!wbc->range_cyclic && req->wb_index > idx_end)
                                 goto out;
 
-                        idx_start = req->wb_index + 1;
+                        /* 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);
+                        dec_zone_page_state(req->wb_page, NR_FILE_DIRTY);
+                        res++;
+                        if (res == LONG_MAX)
+                                goto out;
+                        count--;
+                        if (count == 0)
+                                goto out;
 
-                        if (nfs_set_page_writeback_locked(req)) {
-                                radix_tree_tag_clear(&nfsi->nfs_page_tree,
-                                                req->wb_index, NFS_PAGE_TAG_DIRTY);
-                                nfs_list_remove_request(req);
-                                nfs_list_add_request(req, dst);
-                                dec_zone_page_state(req->wb_page, NR_FILE_DIRTY);
-                                res++;
-                        }
+next:
+                        idx_start = req->wb_index + 1;
                 }
         }
 out:
+        wbc->nr_to_write = count;
+        WARN_ON ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty));
         return res;
 }
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 1d72096c4d22..dbc89fa7e9d5 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -79,7 +79,7 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context*,
                                             unsigned int, unsigned int);
 static int nfs_wait_on_write_congestion(struct address_space *, int);
 static int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int);
-static int nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
+static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
 static const struct rpc_call_ops nfs_write_partial_ops;
 static const struct rpc_call_ops nfs_write_full_ops;
 static const struct rpc_call_ops nfs_commit_ops;
@@ -400,10 +400,8 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
                         goto out;
         }
         err = nfs_commit_inode(inode, wb_priority(wbc));
-        if (err > 0) {
-                wbc->nr_to_write -= err;
+        if (err > 0)
                 err = 0;
-        }
 out:
         clear_bit(BDI_write_congested, &bdi->state);
         wake_up_all(&nfs_write_congestion);
@@ -607,31 +605,6 @@ static void nfs_cancel_commit_list(struct list_head *head)
         }
 }
 
-/*
- * nfs_scan_dirty - Scan an inode for dirty requests
- * @inode: NFS inode to scan
- * @dst: destination list
- * @idx_start: lower bound of page->index to scan.
- * @npages: idx_start + npages sets the upper bound to scan.
- *
- * Moves requests from the inode's dirty page list.
- * The requests are *not* checked to ensure that they form a contiguous set.
- */
-static int
-nfs_scan_dirty(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
-{
-        struct nfs_inode *nfsi = NFS_I(inode);
-        int res = 0;
-
-        if (nfsi->ndirty != 0) {
-                res = nfs_scan_lock_dirty(nfsi, dst, idx_start, npages);
-                nfsi->ndirty -= res;
-                if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty))
-                        printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
-        }
-        return res;
-}
-
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 /*
  * nfs_scan_commit - Scan an inode for commit requests
@@ -1467,22 +1440,19 @@ static inline int nfs_commit_list(struct inode *inode, struct list_head *head, i
 }
 #endif
 
-static int nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
+static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
 {
         struct nfs_inode *nfsi = NFS_I(mapping->host);
         LIST_HEAD(head);
-        pgoff_t index = wbc->range_start >> PAGE_CACHE_SHIFT;
-        unsigned long npages = 1 + (wbc->range_end >> PAGE_CACHE_SHIFT) - index;
-        int res;
+        long res;
 
         spin_lock(&nfsi->req_lock);
-        res = nfs_scan_dirty(mapping->host, &head, index, npages);
+        res = nfs_scan_dirty(mapping, wbc, &head);
         spin_unlock(&nfsi->req_lock);
         if (res) {
                 int error = nfs_flush_list(mapping->host, &head, res, how);
                 if (error < 0)
                         return error;
-                wbc->nr_to_write -= res;
         }
         return res;
 }
@@ -1506,13 +1476,21 @@ int nfs_commit_inode(struct inode *inode, int how)
 }
 #endif
 
-int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
+long nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
                 unsigned int npages, int how)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
+        struct address_space *mapping = inode->i_mapping;
+        struct writeback_control wbc = {
+                .bdi = mapping->backing_dev_info,
+                .sync_mode = WB_SYNC_ALL,
+                .nr_to_write = LONG_MAX,
+                .range_start = ((loff_t)idx_start) << PAGE_CACHE_SHIFT,
+                .range_end = ((loff_t)(idx_start + npages - 1)) << PAGE_CACHE_SHIFT,
+        };
         LIST_HEAD(head);
         int nocommit = how & FLUSH_NOCOMMIT;
-        int pages, ret;
+        long pages, ret;
 
         how &= ~FLUSH_NOCOMMIT;
         spin_lock(&nfsi->req_lock);
@@ -1520,7 +1498,7 @@ int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
                 ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
                 if (ret != 0)
                         continue;
-                pages = nfs_scan_dirty(inode, &head, idx_start, npages);
+                pages = nfs_scan_dirty(mapping, &wbc, &head);
                 if (pages != 0) {
                         spin_unlock(&nfsi->req_lock);
                         if (how & FLUSH_INVALIDATE) {