Merge commit 'v2.6.29-rc1' into timers/hrtimers

Conflicts:
	kernel/time/tick-common.c

1 files changed, 730 insertions, 0 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
new file mode 100644
index 000000000000..a20940170274
--- /dev/null
+++ b/fs/btrfs/ordered-data.c
@@ -0,0 +1,730 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include "ctree.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "extent_io.h"
+
+static u64 entry_end(struct btrfs_ordered_extent *entry)
+{
+        if (entry->file_offset + entry->len < entry->file_offset)
+                return (u64)-1;
+        return entry->file_offset + entry->len;
+}
+
+/* returns NULL if the insertion worked, or it returns the node it did find
+ * in the tree
+ */
+static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
+                                   struct rb_node *node)
+{
+        struct rb_node **p = &root->rb_node;
+        struct rb_node *parent = NULL;
+        struct btrfs_ordered_extent *entry;
+
+        while (*p) {
+                parent = *p;
+                entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
+
+                if (file_offset < entry->file_offset)
+                        p = &(*p)->rb_left;
+                else if (file_offset >= entry_end(entry))
+                        p = &(*p)->rb_right;
+                else
+                        return parent;
+        }
+
+        rb_link_node(node, parent, p);
+        rb_insert_color(node, root);
+        return NULL;
+}
+
+/*
+ * look for a given offset in the tree, and if it can't be found return the
+ * first lesser offset
+ */
+static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
+                                     struct rb_node **prev_ret)
+{
+        struct rb_node *n = root->rb_node;
+        struct rb_node *prev = NULL;
+        struct rb_node *test;
+        struct btrfs_ordered_extent *entry;
+        struct btrfs_ordered_extent *prev_entry = NULL;
+
+        while (n) {
+                entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
+                prev = n;
+                prev_entry = entry;
+
+                if (file_offset < entry->file_offset)
+                        n = n->rb_left;
+                else if (file_offset >= entry_end(entry))
+                        n = n->rb_right;
+                else
+                        return n;
+        }
+        if (!prev_ret)
+                return NULL;
+
+        while (prev && file_offset >= entry_end(prev_entry)) {
+                test = rb_next(prev);
+                if (!test)
+                        break;
+                prev_entry = rb_entry(test, struct btrfs_ordered_extent,
+                                      rb_node);
+                if (file_offset < entry_end(prev_entry))
+                        break;
+
+                prev = test;
+        }
+        if (prev)
+                prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
+                                      rb_node);
+        while (prev && file_offset < entry_end(prev_entry)) {
+                test = rb_prev(prev);
+                if (!test)
+                        break;
+                prev_entry = rb_entry(test, struct btrfs_ordered_extent,
+                                      rb_node);
+                prev = test;
+        }
+        *prev_ret = prev;
+        return NULL;
+}
+
+/*
+ * helper to check if a given offset is inside a given entry
+ */
+static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
+{
+        if (file_offset < entry->file_offset ||
+            entry->file_offset + entry->len <= file_offset)
+                return 0;
+        return 1;
+}
+
+/*
+ * look find the first ordered struct that has this offset, otherwise
+ * the first one less than this offset
+ */
+static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
+                                          u64 file_offset)
+{
+        struct rb_root *root = &tree->tree;
+        struct rb_node *prev;
+        struct rb_node *ret;
+        struct btrfs_ordered_extent *entry;
+
+        if (tree->last) {
+                entry = rb_entry(tree->last, struct btrfs_ordered_extent,
+                                 rb_node);
+                if (offset_in_entry(entry, file_offset))
+                        return tree->last;
+        }
+        ret = __tree_search(root, file_offset, &prev);
+        if (!ret)
+                ret = prev;
+        if (ret)
+                tree->last = ret;
+        return ret;
+}
+
+/* allocate and add a new ordered_extent into the per-inode tree.
+ * file_offset is the logical offset in the file
+ *
+ * start is the disk block number of an extent already reserved in the
+ * extent allocation tree
+ *
+ * len is the length of the extent
+ *
+ * This also sets the EXTENT_ORDERED bit on the range in the inode.
+ *
+ * The tree is given a single reference on the ordered extent that was
+ * inserted.
+ */
+int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
+                             u64 start, u64 len, u64 disk_len, int type)
+{
+        struct btrfs_ordered_inode_tree *tree;
+        struct rb_node *node;
+        struct btrfs_ordered_extent *entry;
+
+        tree = &BTRFS_I(inode)->ordered_tree;
+        entry = kzalloc(sizeof(*entry), GFP_NOFS);
+        if (!entry)
+                return -ENOMEM;
+
+        mutex_lock(&tree->mutex);
+        entry->file_offset = file_offset;
+        entry->start = start;
+        entry->len = len;
+        entry->disk_len = disk_len;
+        entry->inode = inode;
+        if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
+                set_bit(type, &entry->flags);
+
+        /* one ref for the tree */
+        atomic_set(&entry->refs, 1);
+        init_waitqueue_head(&entry->wait);
+        INIT_LIST_HEAD(&entry->list);
+        INIT_LIST_HEAD(&entry->root_extent_list);
+
+        node = tree_insert(&tree->tree, file_offset,
+                           &entry->rb_node);
+        BUG_ON(node);
+
+        set_extent_ordered(&BTRFS_I(inode)->io_tree, file_offset,
+                           entry_end(entry) - 1, GFP_NOFS);
+
+        spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+        list_add_tail(&entry->root_extent_list,
+                      &BTRFS_I(inode)->root->fs_info->ordered_extents);
+        spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+
+        mutex_unlock(&tree->mutex);
+        BUG_ON(node);
+        return 0;
+}
+
+/*
+ * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
+ * when an ordered extent is finished.  If the list covers more than one
+ * ordered extent, it is split across multiples.
+ */
+int btrfs_add_ordered_sum(struct inode *inode,
+                          struct btrfs_ordered_extent *entry,
+                          struct btrfs_ordered_sum *sum)
+{
+        struct btrfs_ordered_inode_tree *tree;
+
+        tree = &BTRFS_I(inode)->ordered_tree;
+        mutex_lock(&tree->mutex);
+        list_add_tail(&sum->list, &entry->list);
+        mutex_unlock(&tree->mutex);
+        return 0;
+}
+
+/*
+ * this is used to account for finished IO across a given range
+ * of the file.  The IO should not span ordered extents.  If
+ * a given ordered_extent is completely done, 1 is returned, otherwise
+ * 0.
+ *
+ * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
+ * to make sure this function only returns 1 once for a given ordered extent.
+ */
+int btrfs_dec_test_ordered_pending(struct inode *inode,
+                                   u64 file_offset, u64 io_size)
+{
+        struct btrfs_ordered_inode_tree *tree;
+        struct rb_node *node;
+        struct btrfs_ordered_extent *entry;
+        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+        int ret;
+
+        tree = &BTRFS_I(inode)->ordered_tree;
+        mutex_lock(&tree->mutex);
+        clear_extent_ordered(io_tree, file_offset, file_offset + io_size - 1,
+                             GFP_NOFS);
+        node = tree_search(tree, file_offset);
+        if (!node) {
+                ret = 1;
+                goto out;
+        }
+
+        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+        if (!offset_in_entry(entry, file_offset)) {
+                ret = 1;
+                goto out;
+        }
+
+        ret = test_range_bit(io_tree, entry->file_offset,
+                             entry->file_offset + entry->len - 1,
+                             EXTENT_ORDERED, 0);
+        if (ret == 0)
+                ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+out:
+        mutex_unlock(&tree->mutex);
+        return ret == 0;
+}
+
+/*
+ * used to drop a reference on an ordered extent.  This will free
+ * the extent if the last reference is dropped
+ */
+int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
+{
+        struct list_head *cur;
+        struct btrfs_ordered_sum *sum;
+
+        if (atomic_dec_and_test(&entry->refs)) {
+                while (!list_empty(&entry->list)) {
+                        cur = entry->list.next;
+                        sum = list_entry(cur, struct btrfs_ordered_sum, list);
+                        list_del(&sum->list);
+                        kfree(sum);
+                }
+                kfree(entry);
+        }
+        return 0;
+}
+
+/*
+ * remove an ordered extent from the tree.  No references are dropped
+ * but, anyone waiting on this extent is woken up.
+ */
+int btrfs_remove_ordered_extent(struct inode *inode,
+                                struct btrfs_ordered_extent *entry)
+{
+        struct btrfs_ordered_inode_tree *tree;
+        struct rb_node *node;
+
+        tree = &BTRFS_I(inode)->ordered_tree;
+        mutex_lock(&tree->mutex);
+        node = &entry->rb_node;
+        rb_erase(node, &tree->tree);
+        tree->last = NULL;
+        set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
+
+        spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+        list_del_init(&entry->root_extent_list);
+        spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+
+        mutex_unlock(&tree->mutex);
+        wake_up(&entry->wait);
+        return 0;
+}
+
+/*
+ * wait for all the ordered extents in a root.  This is done when balancing
+ * space between drives.
+ */
+int btrfs_wait_ordered_extents(struct btrfs_root *root, int nocow_only)
+{
+        struct list_head splice;
+        struct list_head *cur;
+        struct btrfs_ordered_extent *ordered;
+        struct inode *inode;
+
+        INIT_LIST_HEAD(&splice);
+
+        spin_lock(&root->fs_info->ordered_extent_lock);
+        list_splice_init(&root->fs_info->ordered_extents, &splice);
+        while (!list_empty(&splice)) {
+                cur = splice.next;
+                ordered = list_entry(cur, struct btrfs_ordered_extent,
+                                     root_extent_list);
+                if (nocow_only &&
+                    !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags) &&
+                    !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
+                        list_move(&ordered->root_extent_list,
+                                  &root->fs_info->ordered_extents);
+                        cond_resched_lock(&root->fs_info->ordered_extent_lock);
+                        continue;
+                }
+
+                list_del_init(&ordered->root_extent_list);
+                atomic_inc(&ordered->refs);
+
+                /*
+                 * the inode may be getting freed (in sys_unlink path).
+                 */
+                inode = igrab(ordered->inode);
+
+                spin_unlock(&root->fs_info->ordered_extent_lock);
+
+                if (inode) {
+                        btrfs_start_ordered_extent(inode, ordered, 1);
+                        btrfs_put_ordered_extent(ordered);
+                        iput(inode);
+                } else {
+                        btrfs_put_ordered_extent(ordered);
+                }
+
+                spin_lock(&root->fs_info->ordered_extent_lock);
+        }
+        spin_unlock(&root->fs_info->ordered_extent_lock);
+        return 0;
+}
+
+/*
+ * Used to start IO or wait for a given ordered extent to finish.
+ *
+ * If wait is one, this effectively waits on page writeback for all the pages
+ * in the extent, and it waits on the io completion code to insert
+ * metadata into the btree corresponding to the extent
+ */
+void btrfs_start_ordered_extent(struct inode *inode,
+                                       struct btrfs_ordered_extent *entry,
+                                       int wait)
+{
+        u64 start = entry->file_offset;
+        u64 end = start + entry->len - 1;
+
+        /*
+         * pages in the range can be dirty, clean or writeback.  We
+         * start IO on any dirty ones so the wait doesn't stall waiting
+         * for pdflush to find them
+         */
+        btrfs_fdatawrite_range(inode->i_mapping, start, end, WB_SYNC_ALL);
+        if (wait) {
+                wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
+                                                 &entry->flags));
+        }
+}
+
+/*
+ * Used to wait on ordered extents across a large range of bytes.
+ */
+int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
+{
+        u64 end;
+        u64 orig_end;
+        u64 wait_end;
+        struct btrfs_ordered_extent *ordered;
+
+        if (start + len < start) {
+                orig_end = INT_LIMIT(loff_t);
+        } else {
+                orig_end = start + len - 1;
+                if (orig_end > INT_LIMIT(loff_t))
+                        orig_end = INT_LIMIT(loff_t);
+        }
+        wait_end = orig_end;
+again:
+        /* start IO across the range first to instantiate any delalloc
+         * extents
+         */
+        btrfs_fdatawrite_range(inode->i_mapping, start, orig_end, WB_SYNC_NONE);
+
+        /* The compression code will leave pages locked but return from
+         * writepage without setting the page writeback.  Starting again
+         * with WB_SYNC_ALL will end up waiting for the IO to actually start.
+         */
+        btrfs_fdatawrite_range(inode->i_mapping, start, orig_end, WB_SYNC_ALL);
+
+        btrfs_wait_on_page_writeback_range(inode->i_mapping,
+                                           start >> PAGE_CACHE_SHIFT,
+                                           orig_end >> PAGE_CACHE_SHIFT);
+
+        end = orig_end;
+        while (1) {
+                ordered = btrfs_lookup_first_ordered_extent(inode, end);
+                if (!ordered)
+                        break;
+                if (ordered->file_offset > orig_end) {
+                        btrfs_put_ordered_extent(ordered);
+                        break;
+                }
+                if (ordered->file_offset + ordered->len < start) {
+                        btrfs_put_ordered_extent(ordered);
+                        break;
+                }
+                btrfs_start_ordered_extent(inode, ordered, 1);
+                end = ordered->file_offset;
+                btrfs_put_ordered_extent(ordered);
+                if (end == 0 || end == start)
+                        break;
+                end--;
+        }
+        if (test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
+                           EXTENT_ORDERED | EXTENT_DELALLOC, 0)) {
+                schedule_timeout(1);
+                goto again;
+        }
+        return 0;
+}
+
+/*
+ * find an ordered extent corresponding to file_offset.  return NULL if
+ * nothing is found, otherwise take a reference on the extent and return it
+ */
+struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
+                                                         u64 file_offset)
+{
+        struct btrfs_ordered_inode_tree *tree;
+        struct rb_node *node;
+        struct btrfs_ordered_extent *entry = NULL;
+
+        tree = &BTRFS_I(inode)->ordered_tree;
+        mutex_lock(&tree->mutex);
+        node = tree_search(tree, file_offset);
+        if (!node)
+                goto out;
+
+        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+        if (!offset_in_entry(entry, file_offset))
+                entry = NULL;
+        if (entry)
+                atomic_inc(&entry->refs);
+out:
+        mutex_unlock(&tree->mutex);
+        return entry;
+}
+
+/*
+ * lookup and return any extent before 'file_offset'.  NULL is returned
+ * if none is found
+ */
+struct btrfs_ordered_extent *
+btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
+{
+        struct btrfs_ordered_inode_tree *tree;
+        struct rb_node *node;
+        struct btrfs_ordered_extent *entry = NULL;
+
+        tree = &BTRFS_I(inode)->ordered_tree;
+        mutex_lock(&tree->mutex);
+        node = tree_search(tree, file_offset);
+        if (!node)
+                goto out;
+
+        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+        atomic_inc(&entry->refs);
+out:
+        mutex_unlock(&tree->mutex);
+        return entry;
+}
+
+/*
+ * After an extent is done, call this to conditionally update the on disk
+ * i_size.  i_size is updated to cover any fully written part of the file.
+ */
+int btrfs_ordered_update_i_size(struct inode *inode,
+                                struct btrfs_ordered_extent *ordered)
+{
+        struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
+        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+        u64 disk_i_size;
+        u64 new_i_size;
+        u64 i_size_test;
+        struct rb_node *node;
+        struct btrfs_ordered_extent *test;
+
+        mutex_lock(&tree->mutex);
+        disk_i_size = BTRFS_I(inode)->disk_i_size;
+
+        /*
+         * if the disk i_size is already at the inode->i_size, or
+         * this ordered extent is inside the disk i_size, we're done
+         */
+        if (disk_i_size >= inode->i_size ||
+            ordered->file_offset + ordered->len <= disk_i_size) {
+                goto out;
+        }
+
+        /*
+         * we can't update the disk_isize if there are delalloc bytes
+         * between disk_i_size and  this ordered extent
+         */
+        if (test_range_bit(io_tree, disk_i_size,
+                           ordered->file_offset + ordered->len - 1,
+                           EXTENT_DELALLOC, 0)) {
+                goto out;
+        }
+        /*
+         * walk backward from this ordered extent to disk_i_size.
+         * if we find an ordered extent then we can't update disk i_size
+         * yet
+         */
+        node = &ordered->rb_node;
+        while (1) {
+                node = rb_prev(node);
+                if (!node)
+                        break;
+                test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+                if (test->file_offset + test->len <= disk_i_size)
+                        break;
+                if (test->file_offset >= inode->i_size)
+                        break;
+                if (test->file_offset >= disk_i_size)
+                        goto out;
+        }
+        new_i_size = min_t(u64, entry_end(ordered), i_size_read(inode));
+
+        /*
+         * at this point, we know we can safely update i_size to at least
+         * the offset from this ordered extent.  But, we need to
+         * walk forward and see if ios from higher up in the file have
+         * finished.
+         */
+        node = rb_next(&ordered->rb_node);
+        i_size_test = 0;
+        if (node) {
+                /*
+                 * do we have an area where IO might have finished
+                 * between our ordered extent and the next one.
+                 */
+                test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+                if (test->file_offset > entry_end(ordered))
+                        i_size_test = test->file_offset;
+        } else {
+                i_size_test = i_size_read(inode);
+        }
+
+        /*
+         * i_size_test is the end of a region after this ordered
+         * extent where there are no ordered extents.  As long as there
+         * are no delalloc bytes in this area, it is safe to update
+         * disk_i_size to the end of the region.
+         */
+        if (i_size_test > entry_end(ordered) &&
+            !test_range_bit(io_tree, entry_end(ordered), i_size_test - 1,
+                           EXTENT_DELALLOC, 0)) {
+                new_i_size = min_t(u64, i_size_test, i_size_read(inode));
+        }
+        BTRFS_I(inode)->disk_i_size = new_i_size;
+out:
+        mutex_unlock(&tree->mutex);
+        return 0;
+}
+
+/*
+ * search the ordered extents for one corresponding to 'offset' and
+ * try to find a checksum.  This is used because we allow pages to
+ * be reclaimed before their checksum is actually put into the btree
+ */
+int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
+                           u32 *sum)
+{
+        struct btrfs_ordered_sum *ordered_sum;
+        struct btrfs_sector_sum *sector_sums;
+        struct btrfs_ordered_extent *ordered;
+        struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
+        struct list_head *cur;
+        unsigned long num_sectors;
+        unsigned long i;
+        u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
+        int ret = 1;
+
+        ordered = btrfs_lookup_ordered_extent(inode, offset);
+        if (!ordered)
+                return 1;
+
+        mutex_lock(&tree->mutex);
+        list_for_each_prev(cur, &ordered->list) {
+                ordered_sum = list_entry(cur, struct btrfs_ordered_sum, list);
+                if (disk_bytenr >= ordered_sum->bytenr) {
+                        num_sectors = ordered_sum->len / sectorsize;
+                        sector_sums = ordered_sum->sums;
+                        for (i = 0; i < num_sectors; i++) {
+                                if (sector_sums[i].bytenr == disk_bytenr) {
+                                        *sum = sector_sums[i].sum;
+                                        ret = 0;
+                                        goto out;
+                                }
+                        }
+                }
+        }
+out:
+        mutex_unlock(&tree->mutex);
+        btrfs_put_ordered_extent(ordered);
+        return ret;
+}
+
+
+/**
+ * taken from mm/filemap.c because it isn't exported
+ *
+ * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
+ * @mapping:    address space structure to write
+ * @start:      offset in bytes where the range starts
+ * @end:        offset in bytes where the range ends (inclusive)
+ * @sync_mode:  enable synchronous operation
+ *
+ * Start writeback against all of a mapping's dirty pages that lie
+ * within the byte offsets <start, end> inclusive.
+ *
+ * If sync_mode is WB_SYNC_ALL then this is a "data integrity" operation, as
+ * opposed to a regular memory cleansing writeback.  The difference between
+ * these two operations is that if a dirty page/buffer is encountered, it must
+ * be waited upon, and not just skipped over.
+ */
+int btrfs_fdatawrite_range(struct address_space *mapping, loff_t start,
+                           loff_t end, int sync_mode)
+{
+        struct writeback_control wbc = {
+                .sync_mode = sync_mode,
+                .nr_to_write = mapping->nrpages * 2,
+                .range_start = start,
+                .range_end = end,
+                .for_writepages = 1,
+        };
+        return btrfs_writepages(mapping, &wbc);
+}
+
+/**
+ * taken from mm/filemap.c because it isn't exported
+ *
+ * wait_on_page_writeback_range - wait for writeback to complete
+ * @mapping:    target address_space
+ * @start:      beginning page index
+ * @end:        ending page index
+ *
+ * Wait for writeback to complete against pages indexed by start->end
+ * inclusive
+ */
+int btrfs_wait_on_page_writeback_range(struct address_space *mapping,
+                                       pgoff_t start, pgoff_t end)
+{
+        struct pagevec pvec;
+        int nr_pages;
+        int ret = 0;
+        pgoff_t index;
+
+        if (end < start)
+                return 0;
+
+        pagevec_init(&pvec, 0);
+        index = start;
+        while ((index <= end) &&
+                        (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+                        PAGECACHE_TAG_WRITEBACK,
+                        min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) {
+                unsigned i;
+
+                for (i = 0; i < nr_pages; i++) {
+                        struct page *page = pvec.pages[i];
+
+                        /* until radix tree lookup accepts end_index */
+                        if (page->index > end)
+                                continue;
+
+                        wait_on_page_writeback(page);
+                        if (PageError(page))
+                                ret = -EIO;
+                }
+                pagevec_release(&pvec);
+                cond_resched();
+        }
+
+        /* Check for outstanding write errors */
+        if (test_and_clear_bit(AS_ENOSPC, &mapping->flags))
+                ret = -ENOSPC;
+        if (test_and_clear_bit(AS_EIO, &mapping->flags))
+                ret = -EIO;
+
+        return ret;
+}