1 files changed, 735 insertions, 200 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 7055d11c1efd..be1bf627a14b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -17,6 +17,7 @@
 #include "compat.h"
 #include "ctree.h"
 #include "btrfs_inode.h"
+#include "volumes.h"
 
 static struct kmem_cache *extent_state_cache;
 static struct kmem_cache *extent_buffer_cache;
@@ -254,14 +255,14 @@ static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
  *
  * This should be called with the tree lock held.
  */
-static int merge_state(struct extent_io_tree *tree,
-                       struct extent_state *state)
+static void merge_state(struct extent_io_tree *tree,
+                        struct extent_state *state)
 {
         struct extent_state *other;
         struct rb_node *other_node;
 
         if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY))
-                return 0;
+                return;
 
         other_node = rb_prev(&state->rb_node);
         if (other_node) {
@@ -281,26 +282,19 @@ static int merge_state(struct extent_io_tree *tree,
                 if (other->start == state->end + 1 &&
                     other->state == state->state) {
                         merge_cb(tree, state, other);
-                        other->start = state->start;
-                        state->tree = NULL;
-                        rb_erase(&state->rb_node, &tree->state);
-                        free_extent_state(state);
-                        state = NULL;
+                        state->end = other->end;
+                        other->tree = NULL;
+                        rb_erase(&other->rb_node, &tree->state);
+                        free_extent_state(other);
                 }
         }
-
-        return 0;
 }
 
-static int set_state_cb(struct extent_io_tree *tree,
+static void set_state_cb(struct extent_io_tree *tree,
                          struct extent_state *state, int *bits)
 {
-        if (tree->ops && tree->ops->set_bit_hook) {
-                return tree->ops->set_bit_hook(tree->mapping->host,
-                                               state, bits);
-        }
-
-        return 0;
+        if (tree->ops && tree->ops->set_bit_hook)
+                tree->ops->set_bit_hook(tree->mapping->host, state, bits);
 }
 
 static void clear_state_cb(struct extent_io_tree *tree,
@@ -310,6 +304,9 @@ static void clear_state_cb(struct extent_io_tree *tree,
                 tree->ops->clear_bit_hook(tree->mapping->host, state, bits);
 }
 
+static void set_state_bits(struct extent_io_tree *tree,
+                           struct extent_state *state, int *bits);
+
 /*
  * insert an extent_state struct into the tree.  'bits' are set on the
  * struct before it is inserted.
@@ -325,8 +322,6 @@ static int insert_state(struct extent_io_tree *tree,
                         int *bits)
 {
         struct rb_node *node;
-        int bits_to_set = *bits & ~EXTENT_CTLBITS;
-        int ret;
 
         if (end < start) {
                 printk(KERN_ERR "btrfs end < start %llu %llu\n",
@@ -336,13 +331,9 @@ static int insert_state(struct extent_io_tree *tree,
         }
         state->start = start;
         state->end = end;
-        ret = set_state_cb(tree, state, bits);
-        if (ret)
-                return ret;
 
-        if (bits_to_set & EXTENT_DIRTY)
-                tree->dirty_bytes += end - start + 1;
-        state->state |= bits_to_set;
+        set_state_bits(tree, state, bits);
+
         node = tree_insert(&tree->state, end, &state->rb_node);
         if (node) {
                 struct extent_state *found;
@@ -351,7 +342,6 @@ static int insert_state(struct extent_io_tree *tree,
                        "%llu %llu\n", (unsigned long long)found->start,
                        (unsigned long long)found->end,
                        (unsigned long long)start, (unsigned long long)end);
-                free_extent_state(state);
                 return -EEXIST;
         }
         state->tree = tree;
@@ -359,13 +349,11 @@ static int insert_state(struct extent_io_tree *tree,
         return 0;
 }
 
-static int split_cb(struct extent_io_tree *tree, struct extent_state *orig,
+static void split_cb(struct extent_io_tree *tree, struct extent_state *orig,
                      u64 split)
 {
         if (tree->ops && tree->ops->split_extent_hook)
-                return tree->ops->split_extent_hook(tree->mapping->host,
-                                                    orig, split);
-        return 0;
+                tree->ops->split_extent_hook(tree->mapping->host, orig, split);
 }
 
 /*
@@ -500,7 +488,8 @@ again:
                         cached_state = NULL;
                 }
 
-                if (cached && cached->tree && cached->start == start) {
+                if (cached && cached->tree && cached->start <= start &&
+                    cached->end > start) {
                         if (clear)
                                 atomic_dec(&cached->refs);
                         state = cached;
@@ -660,34 +649,25 @@ again:
                 if (start > end)
                         break;
 
-                if (need_resched()) {
-                        spin_unlock(&tree->lock);
-                        cond_resched();
-                        spin_lock(&tree->lock);
-                }
+                cond_resched_lock(&tree->lock);
         }
 out:
         spin_unlock(&tree->lock);
         return 0;
 }
 
-static int set_state_bits(struct extent_io_tree *tree,
+static void set_state_bits(struct extent_io_tree *tree,
                            struct extent_state *state,
                            int *bits)
 {
-        int ret;
         int bits_to_set = *bits & ~EXTENT_CTLBITS;
 
-        ret = set_state_cb(tree, state, bits);
-        if (ret)
-                return ret;
+        set_state_cb(tree, state, bits);
         if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
                 u64 range = state->end - state->start + 1;
                 tree->dirty_bytes += range;
         }
         state->state |= bits_to_set;
-
-        return 0;
 }
 
 static void cache_state(struct extent_state *state,
@@ -742,7 +722,8 @@ again:
         spin_lock(&tree->lock);
         if (cached_state && *cached_state) {
                 state = *cached_state;
-                if (state->start == start && state->tree) {
+                if (state->start <= start && state->end > start &&
+                    state->tree) {
                         node = &state->rb_node;
                         goto hit_next;
                 }
@@ -779,17 +760,15 @@ hit_next:
                         goto out;
                 }
 
-                err = set_state_bits(tree, state, &bits);
-                if (err)
-                        goto out;
+                set_state_bits(tree, state, &bits);
 
-                next_node = rb_next(node);
                 cache_state(state, cached_state);
                 merge_state(tree, state);
                 if (last_end == (u64)-1)
                         goto out;
 
                 start = last_end + 1;
+                next_node = rb_next(&state->rb_node);
                 if (next_node && start < end && prealloc && !need_resched()) {
                         state = rb_entry(next_node, struct extent_state,
                                          rb_node);
@@ -830,9 +809,7 @@ hit_next:
                 if (err)
                         goto out;
                 if (state->end <= end) {
-                        err = set_state_bits(tree, state, &bits);
-                        if (err)
-                                goto out;
+                        set_state_bits(tree, state, &bits);
                         cache_state(state, cached_state);
                         merge_state(tree, state);
                         if (last_end == (u64)-1)
@@ -862,7 +839,6 @@ hit_next:
                  * Avoid to free 'prealloc' if it can be merged with
                  * the later extent.
                  */
-                atomic_inc(&prealloc->refs);
                 err = insert_state(tree, prealloc, start, this_end,
                                    &bits);
                 BUG_ON(err == -EEXIST);
@@ -872,7 +848,6 @@ hit_next:
                         goto out;
                 }
                 cache_state(prealloc, cached_state);
-                free_extent_state(prealloc);
                 prealloc = NULL;
                 start = this_end + 1;
                 goto search_again;
@@ -895,12 +870,196 @@ hit_next:
                 err = split_state(tree, state, prealloc, end + 1);
                 BUG_ON(err == -EEXIST);
 
-                err = set_state_bits(tree, prealloc, &bits);
+                set_state_bits(tree, prealloc, &bits);
+                cache_state(prealloc, cached_state);
+                merge_state(tree, prealloc);
+                prealloc = NULL;
+                goto out;
+        }
+
+        goto search_again;
+
+out:
+        spin_unlock(&tree->lock);
+        if (prealloc)
+                free_extent_state(prealloc);
+
+        return err;
+
+search_again:
+        if (start > end)
+                goto out;
+        spin_unlock(&tree->lock);
+        if (mask & __GFP_WAIT)
+                cond_resched();
+        goto again;
+}
+
+/**
+ * convert_extent - convert all bits in a given range from one bit to another
+ * @tree:       the io tree to search
+ * @start:      the start offset in bytes
+ * @end:        the end offset in bytes (inclusive)
+ * @bits:       the bits to set in this range
+ * @clear_bits: the bits to clear in this range
+ * @mask:       the allocation mask
+ *
+ * This will go through and set bits for the given range.  If any states exist
+ * already in this range they are set with the given bit and cleared of the
+ * clear_bits.  This is only meant to be used by things that are mergeable, ie
+ * converting from say DELALLOC to DIRTY.  This is not meant to be used with
+ * boundary bits like LOCK.
+ */
+int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+                       int bits, int clear_bits, gfp_t mask)
+{
+        struct extent_state *state;
+        struct extent_state *prealloc = NULL;
+        struct rb_node *node;
+        int err = 0;
+        u64 last_start;
+        u64 last_end;
+
+again:
+        if (!prealloc && (mask & __GFP_WAIT)) {
+                prealloc = alloc_extent_state(mask);
+                if (!prealloc)
+                        return -ENOMEM;
+        }
+
+        spin_lock(&tree->lock);
+        /*
+         * this search will find all the extents that end after
+         * our range starts.
+         */
+        node = tree_search(tree, start);
+        if (!node) {
+                prealloc = alloc_extent_state_atomic(prealloc);
+                if (!prealloc)
+                        return -ENOMEM;
+                err = insert_state(tree, prealloc, start, end, &bits);
+                prealloc = NULL;
+                BUG_ON(err == -EEXIST);
+                goto out;
+        }
+        state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
+        last_start = state->start;
+        last_end = state->end;
+
+        /*
+         * | ---- desired range ---- |
+         * | state |
+         *
+         * Just lock what we found and keep going
+         */
+        if (state->start == start && state->end <= end) {
+                struct rb_node *next_node;
+
+                set_state_bits(tree, state, &bits);
+                clear_state_bit(tree, state, &clear_bits, 0);
+
+                merge_state(tree, state);
+                if (last_end == (u64)-1)
+                        goto out;
+
+                start = last_end + 1;
+                next_node = rb_next(&state->rb_node);
+                if (next_node && start < end && prealloc && !need_resched()) {
+                        state = rb_entry(next_node, struct extent_state,
+                                         rb_node);
+                        if (state->start == start)
+                                goto hit_next;
+                }
+                goto search_again;
+        }
+
+        /*
+         *     | ---- desired range ---- |
+         * | state |
+         *   or
+         * | ------------- state -------------- |
+         *
+         * We need to split the extent we found, and may flip bits on
+         * second half.
+         *
+         * If the extent we found extends past our
+         * range, we just split and search again.  It'll get split
+         * again the next time though.
+         *
+         * If the extent we found is inside our range, we set the
+         * desired bit on it.
+         */
+        if (state->start < start) {
+                prealloc = alloc_extent_state_atomic(prealloc);
+                if (!prealloc)
+                        return -ENOMEM;
+                err = split_state(tree, state, prealloc, start);
+                BUG_ON(err == -EEXIST);
+                prealloc = NULL;
+                if (err)
+                        goto out;
+                if (state->end <= end) {
+                        set_state_bits(tree, state, &bits);
+                        clear_state_bit(tree, state, &clear_bits, 0);
+                        merge_state(tree, state);
+                        if (last_end == (u64)-1)
+                                goto out;
+                        start = last_end + 1;
+                }
+                goto search_again;
+        }
+        /*
+         * | ---- desired range ---- |
+         *     | state | or               | state |
+         *
+         * There's a hole, we need to insert something in it and
+         * ignore the extent we found.
+         */
+        if (state->start > start) {
+                u64 this_end;
+                if (end < last_start)
+                        this_end = end;
+                else
+                        this_end = last_start - 1;
+
+                prealloc = alloc_extent_state_atomic(prealloc);
+                if (!prealloc)
+                        return -ENOMEM;
+
+                /*
+                 * Avoid to free 'prealloc' if it can be merged with
+                 * the later extent.
+                 */
+                err = insert_state(tree, prealloc, start, this_end,
+                                   &bits);
+                BUG_ON(err == -EEXIST);
                 if (err) {
+                        free_extent_state(prealloc);
                         prealloc = NULL;
                         goto out;
                 }
-                cache_state(prealloc, cached_state);
+                prealloc = NULL;
+                start = this_end + 1;
+                goto search_again;
+        }
+        /*
+         * | ---- desired range ---- |
+         *                        | state |
+         * We need to split the extent, and set the bit
+         * on the first half
+         */
+        if (state->start <= end && state->end > end) {
+                prealloc = alloc_extent_state_atomic(prealloc);
+                if (!prealloc)
+                        return -ENOMEM;
+
+                err = split_state(tree, state, prealloc, end + 1);
+                BUG_ON(err == -EEXIST);
+
+                set_state_bits(tree, prealloc, &bits);
+                clear_state_bit(tree, prealloc, &clear_bits, 0);
+
                 merge_state(tree, prealloc);
                 prealloc = NULL;
                 goto out;
@@ -949,7 +1108,7 @@ int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
                         struct extent_state **cached_state, gfp_t mask)
 {
         return set_extent_bit(tree, start, end,
-                              EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
+                              EXTENT_DELALLOC | EXTENT_UPTODATE,
                               0, NULL, cached_state, mask);
 }
 
@@ -1061,46 +1220,6 @@ static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
         return 0;
 }
 
-/*
- * find the first offset in the io tree with 'bits' set. zero is
- * returned if we find something, and *start_ret and *end_ret are
- * set to reflect the state struct that was found.
- *
- * If nothing was found, 1 is returned, < 0 on error
- */
-int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
-                          u64 *start_ret, u64 *end_ret, int bits)
-{
-        struct rb_node *node;
-        struct extent_state *state;
-        int ret = 1;
-
-        spin_lock(&tree->lock);
-        /*
-         * this search will find all the extents that end after
-         * our range starts.
-         */
-        node = tree_search(tree, start);
-        if (!node)
-                goto out;
-
-        while (1) {
-                state = rb_entry(node, struct extent_state, rb_node);
-                if (state->end >= start && (state->state & bits)) {
-                        *start_ret = state->start;
-                        *end_ret = state->end;
-                        ret = 0;
-                        break;
-                }
-                node = rb_next(node);
-                if (!node)
-                        break;
-        }
-out:
-        spin_unlock(&tree->lock);
-        return ret;
-}
-
 /* find the first state struct with 'bits' set after 'start', and
  * return it.  tree->lock must be held.  NULL will returned if
  * nothing was found after 'start'
@@ -1133,6 +1252,30 @@ out:
 }
 
 /*
+ * find the first offset in the io tree with 'bits' set. zero is
+ * returned if we find something, and *start_ret and *end_ret are
+ * set to reflect the state struct that was found.
+ *
+ * If nothing was found, 1 is returned, < 0 on error
+ */
+int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
+                          u64 *start_ret, u64 *end_ret, int bits)
+{
+        struct extent_state *state;
+        int ret = 1;
+
+        spin_lock(&tree->lock);
+        state = find_first_extent_bit_state(tree, start, bits);
+        if (state) {
+                *start_ret = state->start;
+                *end_ret = state->end;
+                ret = 0;
+        }
+        spin_unlock(&tree->lock);
+        return ret;
+}
+
+/*
  * find a contiguous range of bytes in the file marked as delalloc, not
  * more than 'max_bytes'.  start and end are used to return the range,
  *
@@ -1564,7 +1707,8 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
         int bitset = 0;
 
         spin_lock(&tree->lock);
-        if (cached && cached->tree && cached->start == start)
+        if (cached && cached->tree && cached->start <= start &&
+            cached->end > start)
                 node = &cached->rb_node;
         else
                 node = tree_search(tree, start);
@@ -1644,6 +1788,368 @@ static int check_page_writeback(struct extent_io_tree *tree,
         return 0;
 }
 
+/*
+ * When IO fails, either with EIO or csum verification fails, we
+ * try other mirrors that might have a good copy of the data.  This
+ * io_failure_record is used to record state as we go through all the
+ * mirrors.  If another mirror has good data, the page is set up to date
+ * and things continue.  If a good mirror can't be found, the original
+ * bio end_io callback is called to indicate things have failed.
+ */
+struct io_failure_record {
+        struct page *page;
+        u64 start;
+        u64 len;
+        u64 logical;
+        unsigned long bio_flags;
+        int this_mirror;
+        int failed_mirror;
+        int in_validation;
+};
+
+static int free_io_failure(struct inode *inode, struct io_failure_record *rec,
+                                int did_repair)
+{
+        int ret;
+        int err = 0;
+        struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
+
+        set_state_private(failure_tree, rec->start, 0);
+        ret = clear_extent_bits(failure_tree, rec->start,
+                                rec->start + rec->len - 1,
+                                EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
+        if (ret)
+                err = ret;
+
+        if (did_repair) {
+                ret = clear_extent_bits(&BTRFS_I(inode)->io_tree, rec->start,
+                                        rec->start + rec->len - 1,
+                                        EXTENT_DAMAGED, GFP_NOFS);
+                if (ret && !err)
+                        err = ret;
+        }
+
+        kfree(rec);
+        return err;
+}
+
+static void repair_io_failure_callback(struct bio *bio, int err)
+{
+        complete(bio->bi_private);
+}
+
+/*
+ * this bypasses the standard btrfs submit functions deliberately, as
+ * the standard behavior is to write all copies in a raid setup. here we only
+ * want to write the one bad copy. so we do the mapping for ourselves and issue
+ * submit_bio directly.
+ * to avoid any synchonization issues, wait for the data after writing, which
+ * actually prevents the read that triggered the error from finishing.
+ * currently, there can be no more than two copies of every data bit. thus,
+ * exactly one rewrite is required.
+ */
+int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
+                        u64 length, u64 logical, struct page *page,
+                        int mirror_num)
+{
+        struct bio *bio;
+        struct btrfs_device *dev;
+        DECLARE_COMPLETION_ONSTACK(compl);
+        u64 map_length = 0;
+        u64 sector;
+        struct btrfs_bio *bbio = NULL;
+        int ret;
+
+        BUG_ON(!mirror_num);
+
+        bio = bio_alloc(GFP_NOFS, 1);
+        if (!bio)
+                return -EIO;
+        bio->bi_private = &compl;
+        bio->bi_end_io = repair_io_failure_callback;
+        bio->bi_size = 0;
+        map_length = length;
+
+        ret = btrfs_map_block(map_tree, WRITE, logical,
+                              &map_length, &bbio, mirror_num);
+        if (ret) {
+                bio_put(bio);
+                return -EIO;
+        }
+        BUG_ON(mirror_num != bbio->mirror_num);
+        sector = bbio->stripes[mirror_num-1].physical >> 9;
+        bio->bi_sector = sector;
+        dev = bbio->stripes[mirror_num-1].dev;
+        kfree(bbio);
+        if (!dev || !dev->bdev || !dev->writeable) {
+                bio_put(bio);
+                return -EIO;
+        }
+        bio->bi_bdev = dev->bdev;
+        bio_add_page(bio, page, length, start-page_offset(page));
+        submit_bio(WRITE_SYNC, bio);
+        wait_for_completion(&compl);
+
+        if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
+                /* try to remap that extent elsewhere? */
+                bio_put(bio);
+                return -EIO;
+        }
+
+        printk(KERN_INFO "btrfs read error corrected: ino %lu off %llu (dev %s "
+                        "sector %llu)\n", page->mapping->host->i_ino, start,
+                        dev->name, sector);
+
+        bio_put(bio);
+        return 0;
+}
+
+/*
+ * each time an IO finishes, we do a fast check in the IO failure tree
+ * to see if we need to process or clean up an io_failure_record
+ */
+static int clean_io_failure(u64 start, struct page *page)
+{
+        u64 private;
+        u64 private_failure;
+        struct io_failure_record *failrec;
+        struct btrfs_mapping_tree *map_tree;
+        struct extent_state *state;
+        int num_copies;
+        int did_repair = 0;
+        int ret;
+        struct inode *inode = page->mapping->host;
+
+        private = 0;
+        ret = count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
+                                (u64)-1, 1, EXTENT_DIRTY, 0);
+        if (!ret)
+                return 0;
+
+        ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
+                                &private_failure);
+        if (ret)
+                return 0;
+
+        failrec = (struct io_failure_record *)(unsigned long) private_failure;
+        BUG_ON(!failrec->this_mirror);
+
+        if (failrec->in_validation) {
+                /* there was no real error, just free the record */
+                pr_debug("clean_io_failure: freeing dummy error at %llu\n",
+                         failrec->start);
+                did_repair = 1;
+                goto out;
+        }
+
+        spin_lock(&BTRFS_I(inode)->io_tree.lock);
+        state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
+                                            failrec->start,
+                                            EXTENT_LOCKED);
+        spin_unlock(&BTRFS_I(inode)->io_tree.lock);
+
+        if (state && state->start == failrec->start) {
+                map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
+                num_copies = btrfs_num_copies(map_tree, failrec->logical,
+                                                failrec->len);
+                if (num_copies > 1)  {
+                        ret = repair_io_failure(map_tree, start, failrec->len,
+                                                failrec->logical, page,
+                                                failrec->failed_mirror);
+                        did_repair = !ret;
+                }
+        }
+
+out:
+        if (!ret)
+                ret = free_io_failure(inode, failrec, did_repair);
+
+        return ret;
+}
+
+/*
+ * this is a generic handler for readpage errors (default
+ * readpage_io_failed_hook). if other copies exist, read those and write back
+ * good data to the failed position. does not investigate in remapping the
+ * failed extent elsewhere, hoping the device will be smart enough to do this as
+ * needed
+ */
+
+static int bio_readpage_error(struct bio *failed_bio, struct page *page,
+                                u64 start, u64 end, int failed_mirror,
+                                struct extent_state *state)
+{
+        struct io_failure_record *failrec = NULL;
+        u64 private;
+        struct extent_map *em;
+        struct inode *inode = page->mapping->host;
+        struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
+        struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
+        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+        struct bio *bio;
+        int num_copies;
+        int ret;
+        int read_mode;
+        u64 logical;
+
+        BUG_ON(failed_bio->bi_rw & REQ_WRITE);
+
+        ret = get_state_private(failure_tree, start, &private);
+        if (ret) {
+                failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
+                if (!failrec)
+                        return -ENOMEM;
+                failrec->start = start;
+                failrec->len = end - start + 1;
+                failrec->this_mirror = 0;
+                failrec->bio_flags = 0;
+                failrec->in_validation = 0;
+
+                read_lock(&em_tree->lock);
+                em = lookup_extent_mapping(em_tree, start, failrec->len);
+                if (!em) {
+                        read_unlock(&em_tree->lock);
+                        kfree(failrec);
+                        return -EIO;
+                }
+
+                if (em->start > start || em->start + em->len < start) {
+                        free_extent_map(em);
+                        em = NULL;
+                }
+                read_unlock(&em_tree->lock);
+
+                if (!em || IS_ERR(em)) {
+                        kfree(failrec);
+                        return -EIO;
+                }
+                logical = start - em->start;
+                logical = em->block_start + logical;
+                if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
+                        logical = em->block_start;
+                        failrec->bio_flags = EXTENT_BIO_COMPRESSED;
+                        extent_set_compress_type(&failrec->bio_flags,
+                                                 em->compress_type);
+                }
+                pr_debug("bio_readpage_error: (new) logical=%llu, start=%llu, "
+                         "len=%llu\n", logical, start, failrec->len);
+                failrec->logical = logical;
+                free_extent_map(em);
+
+                /* set the bits in the private failure tree */
+                ret = set_extent_bits(failure_tree, start, end,
+                                        EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
+                if (ret >= 0)
+                        ret = set_state_private(failure_tree, start,
+                                                (u64)(unsigned long)failrec);
+                /* set the bits in the inode's tree */
+                if (ret >= 0)
+                        ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
+                                                GFP_NOFS);
+                if (ret < 0) {
+                        kfree(failrec);
+                        return ret;
+                }
+        } else {
+                failrec = (struct io_failure_record *)(unsigned long)private;
+                pr_debug("bio_readpage_error: (found) logical=%llu, "
+                         "start=%llu, len=%llu, validation=%d\n",
+                         failrec->logical, failrec->start, failrec->len,
+                         failrec->in_validation);
+                /*
+                 * when data can be on disk more than twice, add to failrec here
+                 * (e.g. with a list for failed_mirror) to make
+                 * clean_io_failure() clean all those errors at once.
+                 */
+        }
+        num_copies = btrfs_num_copies(
+                              &BTRFS_I(inode)->root->fs_info->mapping_tree,
+                              failrec->logical, failrec->len);
+        if (num_copies == 1) {
+                /*
+                 * we only have a single copy of the data, so don't bother with
+                 * all the retry and error correction code that follows. no
+                 * matter what the error is, it is very likely to persist.
+                 */
+                pr_debug("bio_readpage_error: cannot repair, num_copies == 1. "
+                         "state=%p, num_copies=%d, next_mirror %d, "
+                         "failed_mirror %d\n", state, num_copies,
+                         failrec->this_mirror, failed_mirror);
+                free_io_failure(inode, failrec, 0);
+                return -EIO;
+        }
+
+        if (!state) {
+                spin_lock(&tree->lock);
+                state = find_first_extent_bit_state(tree, failrec->start,
+                                                    EXTENT_LOCKED);
+                if (state && state->start != failrec->start)
+                        state = NULL;
+                spin_unlock(&tree->lock);
+        }
+
+        /*
+         * there are two premises:
+         *      a) deliver good data to the caller
+         *      b) correct the bad sectors on disk
+         */
+        if (failed_bio->bi_vcnt > 1) {
+                /*
+                 * to fulfill b), we need to know the exact failing sectors, as
+                 * we don't want to rewrite any more than the failed ones. thus,
+                 * we need separate read requests for the failed bio
+                 *
+                 * if the following BUG_ON triggers, our validation request got
+                 * merged. we need separate requests for our algorithm to work.
+                 */
+                BUG_ON(failrec->in_validation);
+                failrec->in_validation = 1;
+                failrec->this_mirror = failed_mirror;
+                read_mode = READ_SYNC | REQ_FAILFAST_DEV;
+        } else {
+                /*
+                 * we're ready to fulfill a) and b) alongside. get a good copy
+                 * of the failed sector and if we succeed, we have setup
+                 * everything for repair_io_failure to do the rest for us.
+                 */
+                if (failrec->in_validation) {
+                        BUG_ON(failrec->this_mirror != failed_mirror);
+                        failrec->in_validation = 0;
+                        failrec->this_mirror = 0;
+                }
+                failrec->failed_mirror = failed_mirror;
+                failrec->this_mirror++;
+                if (failrec->this_mirror == failed_mirror)
+                        failrec->this_mirror++;
+                read_mode = READ_SYNC;
+        }
+
+        if (!state || failrec->this_mirror > num_copies) {
+                pr_debug("bio_readpage_error: (fail) state=%p, num_copies=%d, "
+                         "next_mirror %d, failed_mirror %d\n", state,
+                         num_copies, failrec->this_mirror, failed_mirror);
+                free_io_failure(inode, failrec, 0);
+                return -EIO;
+        }
+
+        bio = bio_alloc(GFP_NOFS, 1);
+        bio->bi_private = state;
+        bio->bi_end_io = failed_bio->bi_end_io;
+        bio->bi_sector = failrec->logical >> 9;
+        bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
+        bio->bi_size = 0;
+
+        bio_add_page(bio, page, failrec->len, start - page_offset(page));
+
+        pr_debug("bio_readpage_error: submitting new read[%#x] to "
+                 "this_mirror=%d, num_copies=%d, in_validation=%d\n", read_mode,
+                 failrec->this_mirror, num_copies, failrec->in_validation);
+
+        tree->ops->submit_bio_hook(inode, read_mode, bio, failrec->this_mirror,
+                                        failrec->bio_flags, 0);
+        return 0;
+}
+
 /* lots and lots of room for performance fixes in the end_bio funcs */
 
 /*
@@ -1742,6 +2248,9 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                 struct extent_state *cached = NULL;
                 struct extent_state *state;
 
+                pr_debug("end_bio_extent_readpage: bi_vcnt=%d, idx=%d, err=%d, "
+                         "mirror=%ld\n", bio->bi_vcnt, bio->bi_idx, err,
+                         (long int)bio->bi_bdev);
                 tree = &BTRFS_I(page->mapping->host)->io_tree;
 
                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
@@ -1772,12 +2281,26 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                                                               state);
                         if (ret)
                                 uptodate = 0;
+                        else
+                                clean_io_failure(start, page);
                 }
-                if (!uptodate && tree->ops &&
-                    tree->ops->readpage_io_failed_hook) {
-                        ret = tree->ops->readpage_io_failed_hook(bio, page,
-                                                         start, end, NULL);
+                if (!uptodate) {
+                        int failed_mirror;
+                        failed_mirror = (int)(unsigned long)bio->bi_bdev;
+                        /*
+                         * The generic bio_readpage_error handles errors the
+                         * following way: If possible, new read requests are
+                         * created and submitted and will end up in
+                         * end_bio_extent_readpage as well (if we're lucky, not
+                         * in the !uptodate case). In that case it returns 0 and
+                         * we just go on with the next page in our bio. If it
+                         * can't handle the error it will return -EIO and we
+                         * remain responsible for that page.
+                         */
+                        ret = bio_readpage_error(bio, page, start, end,
+                                                        failed_mirror, NULL);
                         if (ret == 0) {
+error_handled:
                                 uptodate =
                                         test_bit(BIO_UPTODATE, &bio->bi_flags);
                                 if (err)
@@ -1785,6 +2308,13 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                                 uncache_state(&cached);
                                 continue;
                         }
+                        if (tree->ops && tree->ops->readpage_io_failed_hook) {
+                                ret = tree->ops->readpage_io_failed_hook(
+                                                        bio, page, start, end,
+                                                        failed_mirror, state);
+                                if (ret == 0)
+                                        goto error_handled;
+                        }
                 }
 
                 if (uptodate) {
@@ -1856,6 +2386,7 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num,
                                            mirror_num, bio_flags, start);
         else
                 submit_bio(rw, bio);
+
         if (bio_flagged(bio, BIO_EOPNOTSUPP))
                 ret = -EOPNOTSUPP;
         bio_put(bio);
@@ -2121,16 +2652,16 @@ out:
 }
 
 int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
-                            get_extent_t *get_extent)
+                            get_extent_t *get_extent, int mirror_num)
 {
         struct bio *bio = NULL;
         unsigned long bio_flags = 0;
         int ret;
 
-        ret = __extent_read_full_page(tree, page, get_extent, &bio, 0,
+        ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
                                       &bio_flags);
         if (bio)
-                ret = submit_one_bio(READ, bio, 0, bio_flags);
+                ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
         return ret;
 }
 
@@ -2181,6 +2712,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         int compressed;
         int write_flags;
         unsigned long nr_written = 0;
+        bool fill_delalloc = true;
 
         if (wbc->sync_mode == WB_SYNC_ALL)
                 write_flags = WRITE_SYNC;
@@ -2190,6 +2722,9 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         trace___extent_writepage(page, inode, wbc);
 
         WARN_ON(!PageLocked(page));
+
+        ClearPageError(page);
+
         pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
         if (page->index > end_index ||
            (page->index == end_index && !pg_offset)) {
@@ -2211,10 +2746,13 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 
         set_page_extent_mapped(page);
 
+        if (!tree->ops || !tree->ops->fill_delalloc)
+                fill_delalloc = false;
+
         delalloc_start = start;
         delalloc_end = 0;
         page_started = 0;
-        if (!epd->extent_locked) {
+        if (!epd->extent_locked && fill_delalloc) {
                 u64 delalloc_to_write = 0;
                 /*
                  * make sure the wbc mapping index is at least updated
@@ -2432,6 +2970,7 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
         pgoff_t index;
         pgoff_t end;            /* Inclusive */
         int scanned = 0;
+        int tag;
 
         pagevec_init(&pvec, 0);
         if (wbc->range_cyclic) {
@@ -2442,11 +2981,16 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
                 scanned = 1;
         }
+        if (wbc->sync_mode == WB_SYNC_ALL)
+                tag = PAGECACHE_TAG_TOWRITE;
+        else
+                tag = PAGECACHE_TAG_DIRTY;
 retry:
+        if (wbc->sync_mode == WB_SYNC_ALL)
+                tag_pages_for_writeback(mapping, index, end);
         while (!done && !nr_to_write_done && (index <= end) &&
-               (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
-                              PAGECACHE_TAG_DIRTY, min(end - index,
-                                  (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
+               (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
+                        min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
                 unsigned i;
 
                 scanned = 1;
@@ -2460,10 +3004,16 @@ retry:
                          * swizzled back from swapper_space to tmpfs file
                          * mapping
                          */
-                        if (tree->ops && tree->ops->write_cache_pages_lock_hook)
-                                tree->ops->write_cache_pages_lock_hook(page);
-                        else
-                                lock_page(page);
+                        if (tree->ops &&
+                            tree->ops->write_cache_pages_lock_hook) {
+                                tree->ops->write_cache_pages_lock_hook(page,
+                                                               data, flush_fn);
+                        } else {
+                                if (!trylock_page(page)) {
+                                        flush_fn(data);
+                                        lock_page(page);
+                                }
+                        }
 
                         if (unlikely(page->mapping != mapping)) {
                                 unlock_page(page);
@@ -2541,7 +3091,6 @@ int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
                           struct writeback_control *wbc)
 {
         int ret;
-        struct address_space *mapping = page->mapping;
         struct extent_page_data epd = {
                 .bio = NULL,
                 .tree = tree,
@@ -2549,18 +3098,9 @@ int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
                 .extent_locked = 0,
                 .sync_io = wbc->sync_mode == WB_SYNC_ALL,
         };
-        struct writeback_control wbc_writepages = {
-                .sync_mode      = wbc->sync_mode,
-                .older_than_this = NULL,
-                .nr_to_write    = 64,
-                .range_start    = page_offset(page) + PAGE_CACHE_SIZE,
-                .range_end      = (loff_t)-1,
-        };
 
         ret = __extent_writepage(page, wbc, &epd);
 
-        extent_write_cache_pages(tree, mapping, &wbc_writepages,
-                                 __extent_writepage, &epd, flush_write_bio);
         flush_epd_write_bio(&epd);
         return ret;
 }
@@ -2584,7 +3124,6 @@ int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
         };
         struct writeback_control wbc_writepages = {
                 .sync_mode      = mode,
-                .older_than_this = NULL,
                 .nr_to_write    = nr_pages * 2,
                 .range_start    = start,
                 .range_end      = end + 1,
@@ -2840,6 +3379,9 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                 return -ENOMEM;
         path->leave_spinning = 1;
 
+        start = ALIGN(start, BTRFS_I(inode)->root->sectorsize);
+        len = ALIGN(len, BTRFS_I(inode)->root->sectorsize);
+
         /*
          * lookup the last file extent.  We're not using i_size here
          * because there might be preallocation past i_size
@@ -2887,7 +3429,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
         lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
                          &cached_state, GFP_NOFS);
 
-        em = get_extent_skip_holes(inode, off, last_for_get_extent,
+        em = get_extent_skip_holes(inode, start, last_for_get_extent,
                                    get_extent);
         if (!em)
                 goto out;
@@ -2976,7 +3518,7 @@ out:
         return ret;
 }
 
-static inline struct page *extent_buffer_page(struct extent_buffer *eb,
+inline struct page *extent_buffer_page(struct extent_buffer *eb,
                                               unsigned long i)
 {
         struct page *p;
@@ -3001,7 +3543,7 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
         return p;
 }
 
-static inline unsigned long num_extent_pages(u64 start, u64 len)
+inline unsigned long num_extent_pages(u64 start, u64 len)
 {
         return ((start + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) -
                 (start >> PAGE_CACHE_SHIFT);
@@ -3022,8 +3564,15 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
                 return NULL;
         eb->start = start;
         eb->len = len;
-        spin_lock_init(&eb->lock);
-        init_waitqueue_head(&eb->lock_wq);
+        rwlock_init(&eb->lock);
+        atomic_set(&eb->write_locks, 0);
+        atomic_set(&eb->read_locks, 0);
+        atomic_set(&eb->blocking_readers, 0);
+        atomic_set(&eb->blocking_writers, 0);
+        atomic_set(&eb->spinning_readers, 0);
+        atomic_set(&eb->spinning_writers, 0);
+        init_waitqueue_head(&eb->write_lock_wq);
+        init_waitqueue_head(&eb->read_lock_wq);
 
 #if LEAK_DEBUG
         spin_lock_irqsave(&leak_lock, flags);
@@ -3119,7 +3668,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
                 i = 0;
         }
         for (; i < num_pages; i++, index++) {
-                p = find_or_create_page(mapping, index, GFP_NOFS | __GFP_HIGHMEM);
+                p = find_or_create_page(mapping, index, GFP_NOFS);
                 if (!p) {
                         WARN_ON(1);
                         goto free_eb;
@@ -3247,6 +3796,7 @@ int clear_extent_buffer_dirty(struct extent_io_tree *tree,
                                                 PAGECACHE_TAG_DIRTY);
                 }
                 spin_unlock_irq(&page->mapping->tree_lock);
+                ClearPageError(page);
                 unlock_page(page);
         }
         return 0;
@@ -3266,6 +3816,22 @@ int set_extent_buffer_dirty(struct extent_io_tree *tree,
         return was_dirty;
 }
 
+static int __eb_straddles_pages(u64 start, u64 len)
+{
+        if (len < PAGE_CACHE_SIZE)
+                return 1;
+        if (start & (PAGE_CACHE_SIZE - 1))
+                return 1;
+        if ((start + len) & (PAGE_CACHE_SIZE - 1))
+                return 1;
+        return 0;
+}
+
+static int eb_straddles_pages(struct extent_buffer *eb)
+{
+        return __eb_straddles_pages(eb->start, eb->len);
+}
+
 int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
                                 struct extent_buffer *eb,
                                 struct extent_state **cached_state)
@@ -3277,8 +3843,10 @@ int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
         num_pages = num_extent_pages(eb->start, eb->len);
         clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
 
-        clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
-                              cached_state, GFP_NOFS);
+        if (eb_straddles_pages(eb)) {
+                clear_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
+                                      cached_state, GFP_NOFS);
+        }
         for (i = 0; i < num_pages; i++) {
                 page = extent_buffer_page(eb, i);
                 if (page)
@@ -3296,8 +3864,10 @@ int set_extent_buffer_uptodate(struct extent_io_tree *tree,
 
         num_pages = num_extent_pages(eb->start, eb->len);
 
-        set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
-                            NULL, GFP_NOFS);
+        if (eb_straddles_pages(eb)) {
+                set_extent_uptodate(tree, eb->start, eb->start + eb->len - 1,
+                                    NULL, GFP_NOFS);
+        }
         for (i = 0; i < num_pages; i++) {
                 page = extent_buffer_page(eb, i);
                 if ((i == 0 && (eb->start & (PAGE_CACHE_SIZE - 1))) ||
@@ -3320,9 +3890,12 @@ int extent_range_uptodate(struct extent_io_tree *tree,
         int uptodate;
         unsigned long index;
 
-        ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL);
-        if (ret)
-                return 1;
+        if (__eb_straddles_pages(start, end - start + 1)) {
+                ret = test_range_bit(tree, start, end,
+                                     EXTENT_UPTODATE, 1, NULL);
+                if (ret)
+                        return 1;
+        }
         while (start <= end) {
                 index = start >> PAGE_CACHE_SHIFT;
                 page = find_get_page(tree->mapping, index);
@@ -3350,10 +3923,12 @@ int extent_buffer_uptodate(struct extent_io_tree *tree,
         if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
                 return 1;
 
-        ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
-                           EXTENT_UPTODATE, 1, cached_state);
-        if (ret)
-                return ret;
+        if (eb_straddles_pages(eb)) {
+                ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
+                                   EXTENT_UPTODATE, 1, cached_state);
+                if (ret)
+                        return ret;
+        }
 
         num_pages = num_extent_pages(eb->start, eb->len);
         for (i = 0; i < num_pages; i++) {
@@ -3367,8 +3942,7 @@ int extent_buffer_uptodate(struct extent_io_tree *tree,
 }
 
 int read_extent_buffer_pages(struct extent_io_tree *tree,
-                             struct extent_buffer *eb,
-                             u64 start, int wait,
+                             struct extent_buffer *eb, u64 start, int wait,
                              get_extent_t *get_extent, int mirror_num)
 {
         unsigned long i;
@@ -3386,9 +3960,11 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
         if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
                 return 0;
 
-        if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
-                           EXTENT_UPTODATE, 1, NULL)) {
-                return 0;
+        if (eb_straddles_pages(eb)) {
+                if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
+                                   EXTENT_UPTODATE, 1, NULL)) {
+                        return 0;
+                }
         }
 
         if (start) {
@@ -3402,7 +3978,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
         num_pages = num_extent_pages(eb->start, eb->len);
         for (i = start_i; i < num_pages; i++) {
                 page = extent_buffer_page(eb, i);
-                if (!wait) {
+                if (wait == WAIT_NONE) {
                         if (!trylock_page(page))
                                 goto unlock_exit;
                 } else {
@@ -3446,7 +4022,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
         if (bio)
                 submit_one_bio(READ, bio, mirror_num, bio_flags);
 
-        if (ret || !wait)
+        if (ret || wait != WAIT_COMPLETE)
                 return ret;
 
         for (i = start_i; i < num_pages; i++) {
@@ -3492,9 +4068,8 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
                 page = extent_buffer_page(eb, i);
 
                 cur = min(len, (PAGE_CACHE_SIZE - offset));
-                kaddr = kmap_atomic(page, KM_USER1);
+                kaddr = page_address(page);
                 memcpy(dst, kaddr + offset, cur);
-                kunmap_atomic(kaddr, KM_USER1);
 
                 dst += cur;
                 len -= cur;
@@ -3504,9 +4079,9 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
 }
 
 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
-                               unsigned long min_len, char **token, char **map,
+                               unsigned long min_len, char **map,
                                unsigned long *map_start,
-                               unsigned long *map_len, int km)
+                               unsigned long *map_len)
 {
         size_t offset = start & (PAGE_CACHE_SIZE - 1);
         char *kaddr;
@@ -3536,42 +4111,12 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
         }
 
         p = extent_buffer_page(eb, i);
-        kaddr = kmap_atomic(p, km);
-        *token = kaddr;
+        kaddr = page_address(p);
         *map = kaddr + offset;
         *map_len = PAGE_CACHE_SIZE - offset;
         return 0;
 }
 
-int map_extent_buffer(struct extent_buffer *eb, unsigned long start,
-                      unsigned long min_len,
-                      char **token, char **map,
-                      unsigned long *map_start,
-                      unsigned long *map_len, int km)
-{
-        int err;
-        int save = 0;
-        if (eb->map_token) {
-                unmap_extent_buffer(eb, eb->map_token, km);
-                eb->map_token = NULL;
-                save = 1;
-        }
-        err = map_private_extent_buffer(eb, start, min_len, token, map,
-                                       map_start, map_len, km);
-        if (!err && save) {
-                eb->map_token = *token;
-                eb->kaddr = *map;
-                eb->map_start = *map_start;
-                eb->map_len = *map_len;
-        }
-        return err;
-}
-
-void unmap_extent_buffer(struct extent_buffer *eb, char *token, int km)
-{
-        kunmap_atomic(token, km);
-}
-
 int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
                           unsigned long start,
                           unsigned long len)
@@ -3595,9 +4140,8 @@ int memcmp_extent_buffer(struct extent_buffer *eb, const void *ptrv,
 
                 cur = min(len, (PAGE_CACHE_SIZE - offset));
 
-                kaddr = kmap_atomic(page, KM_USER0);
+                kaddr = page_address(page);
                 ret = memcmp(ptr, kaddr + offset, cur);
-                kunmap_atomic(kaddr, KM_USER0);
                 if (ret)
                         break;
 
@@ -3630,9 +4174,8 @@ void write_extent_buffer(struct extent_buffer *eb, const void *srcv,
                 WARN_ON(!PageUptodate(page));
 
                 cur = min(len, PAGE_CACHE_SIZE - offset);
-                kaddr = kmap_atomic(page, KM_USER1);
+                kaddr = page_address(page);
                 memcpy(kaddr + offset, src, cur);
-                kunmap_atomic(kaddr, KM_USER1);
 
                 src += cur;
                 len -= cur;
@@ -3661,9 +4204,8 @@ void memset_extent_buffer(struct extent_buffer *eb, char c,
                 WARN_ON(!PageUptodate(page));
 
                 cur = min(len, PAGE_CACHE_SIZE - offset);
-                kaddr = kmap_atomic(page, KM_USER0);
+                kaddr = page_address(page);
                 memset(kaddr + offset, c, cur);
-                kunmap_atomic(kaddr, KM_USER0);
 
                 len -= cur;
                 offset = 0;
@@ -3694,9 +4236,8 @@ void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src,
 
                 cur = min(len, (unsigned long)(PAGE_CACHE_SIZE - offset));
 
-                kaddr = kmap_atomic(page, KM_USER0);
+                kaddr = page_address(page);
                 read_extent_buffer(src, kaddr + offset, src_offset, cur);
-                kunmap_atomic(kaddr, KM_USER0);
 
                 src_offset += cur;
                 len -= cur;
@@ -3709,20 +4250,17 @@ static void move_pages(struct page *dst_page, struct page *src_page,
                        unsigned long dst_off, unsigned long src_off,
                        unsigned long len)
 {
-        char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
+        char *dst_kaddr = page_address(dst_page);
         if (dst_page == src_page) {
                 memmove(dst_kaddr + dst_off, dst_kaddr + src_off, len);
         } else {
-                char *src_kaddr = kmap_atomic(src_page, KM_USER1);
+                char *src_kaddr = page_address(src_page);
                 char *p = dst_kaddr + dst_off + len;
                 char *s = src_kaddr + src_off + len;
 
                 while (len--)
                         *--p = *--s;
-
-                kunmap_atomic(src_kaddr, KM_USER1);
         }
-        kunmap_atomic(dst_kaddr, KM_USER0);
 }
 
 static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
@@ -3735,20 +4273,17 @@ static void copy_pages(struct page *dst_page, struct page *src_page,
                        unsigned long dst_off, unsigned long src_off,
                        unsigned long len)
 {
-        char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
+        char *dst_kaddr = page_address(dst_page);
         char *src_kaddr;
 
         if (dst_page != src_page) {
-                src_kaddr = kmap_atomic(src_page, KM_USER1);
+                src_kaddr = page_address(src_page);
         } else {
                 src_kaddr = dst_kaddr;
                 BUG_ON(areas_overlap(src_off, dst_off, len));
         }
 
         memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
-        kunmap_atomic(dst_kaddr, KM_USER0);
-        if (dst_page != src_page)
-                kunmap_atomic(src_kaddr, KM_USER1);
 }
 
 void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,