Btrfs: Remove broken optimisations in end_bio functions.

These ended up freeing objects while they were still using them. Under
guidance from Chris, just rip out the 'clever' bits and do things the
simple way.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 21 insertions, 138 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f46f88620c70..83ba0c328722 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -15,6 +15,8 @@
 #include "extent_io.h"
 #include "extent_map.h"
 #include "compat.h"
+#include "ctree.h"
+#include "btrfs_inode.h"
 
 /* temporary define until extent_map moves out of btrfs */
 struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
@@ -1394,15 +1396,11 @@ static int end_bio_extent_writepage(struct bio *bio,
 {
         int uptodate = err == 0;
         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-        struct extent_state *state = bio->bi_private;
-        struct extent_io_tree *tree = state->tree;
-        struct rb_node *node;
+        struct extent_io_tree *tree;
         u64 start;
         u64 end;
-        u64 cur;
         int whole_page;
         int ret;
-        unsigned long flags;
 
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
         if (bio->bi_size)
@@ -1410,6 +1408,8 @@ static int end_bio_extent_writepage(struct bio *bio,
 #endif
         do {
                 struct page *page = bvec->bv_page;
+                tree = &BTRFS_I(page->mapping->host)->io_tree;
+
                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
                          bvec->bv_offset;
                 end = start + bvec->bv_len - 1;
@@ -1423,7 +1423,7 @@ static int end_bio_extent_writepage(struct bio *bio,
                         prefetchw(&bvec->bv_page->flags);
                 if (tree->ops && tree->ops->writepage_end_io_hook) {
                         ret = tree->ops->writepage_end_io_hook(page, start,
-                                                       end, state, uptodate);
+                                                       end, NULL, uptodate);
                         if (ret)
                                 uptodate = 0;
                 }
@@ -1431,9 +1431,8 @@ static int end_bio_extent_writepage(struct bio *bio,
                 if (!uptodate && tree->ops &&
                     tree->ops->writepage_io_failed_hook) {
                         ret = tree->ops->writepage_io_failed_hook(bio, page,
-                                                         start, end, state);
+                                                         start, end, NULL);
                         if (ret == 0) {
-                                state = NULL;
                                 uptodate = (err == 0);
                                 continue;
                         }
@@ -1445,68 +1444,7 @@ static int end_bio_extent_writepage(struct bio *bio,
                         SetPageError(page);
                 }
 
-                /*
-                 * bios can get merged in funny ways, and so we need to
-                 * be careful with the state variable.  We know the
-                 * state won't be merged with others because it has
-                 * WRITEBACK set, but we can't be sure each biovec is
-                 * sequential in the file.  So, if our cached state
-                 * doesn't match the expected end, search the tree
-                 * for the correct one.
-                 */
-
-                spin_lock_irqsave(&tree->lock, flags);
-                if (!state || state->end != end) {
-                        state = NULL;
-                        node = __etree_search(tree, start, NULL, NULL);
-                        if (node) {
-                                state = rb_entry(node, struct extent_state,
-                                                 rb_node);
-                                if (state->end != end ||
-                                    !(state->state & EXTENT_WRITEBACK))
-                                        state = NULL;
-                        }
-                        if (!state) {
-                                spin_unlock_irqrestore(&tree->lock, flags);
-                                clear_extent_writeback(tree, start,
-                                                       end, GFP_ATOMIC);
-                                goto next_io;
-                        }
-                }
-                cur = end;
-                while(1) {
-                        struct extent_state *clear = state;
-                        cur = state->start;
-                        node = rb_prev(&state->rb_node);
-                        if (node) {
-                                state = rb_entry(node,
-                                                 struct extent_state,
-                                                 rb_node);
-                        } else {
-                                state = NULL;
-                        }
-
-                        clear_state_bit(tree, clear, EXTENT_WRITEBACK,
-                                        1, 0);
-                        if (cur == start)
-                                break;
-                        if (cur < start) {
-                                WARN_ON(1);
-                                break;
-                        }
-                        if (!node)
-                                break;
-                }
-                /* before releasing the lock, make sure the next state
-                 * variable has the expected bits set and corresponds
-                 * to the correct offsets in the file
-                 */
-                if (state && (state->end + 1 != start ||
-                    !(state->state & EXTENT_WRITEBACK))) {
-                        state = NULL;
-                }
-                spin_unlock_irqrestore(&tree->lock, flags);
-next_io:
+                clear_extent_writeback(tree, start, end, GFP_ATOMIC);
 
                 if (whole_page)
                         end_page_writeback(page);
@@ -1539,13 +1477,9 @@ static int end_bio_extent_readpage(struct bio *bio,
 {
         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-        struct extent_state *state = bio->bi_private;
-        struct extent_io_tree *tree = state->tree;
-        struct rb_node *node;
+        struct extent_io_tree *tree;
         u64 start;
         u64 end;
-        u64 cur;
-        unsigned long flags;
         int whole_page;
         int ret;
 
@@ -1556,6 +1490,8 @@ static int end_bio_extent_readpage(struct bio *bio,
 
         do {
                 struct page *page = bvec->bv_page;
+                tree = &BTRFS_I(page->mapping->host)->io_tree;
+
                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
                         bvec->bv_offset;
                 end = start + bvec->bv_len - 1;
@@ -1570,80 +1506,26 @@ static int end_bio_extent_readpage(struct bio *bio,
 
                 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
                         ret = tree->ops->readpage_end_io_hook(page, start, end,
-                                                              state);
+                                                              NULL);
                         if (ret)
                                 uptodate = 0;
                 }
                 if (!uptodate && tree->ops &&
                     tree->ops->readpage_io_failed_hook) {
                         ret = tree->ops->readpage_io_failed_hook(bio, page,
-                                                         start, end, state);
+                                                         start, end, NULL);
                         if (ret == 0) {
-                                state = NULL;
                                 uptodate =
                                         test_bit(BIO_UPTODATE, &bio->bi_flags);
                                 continue;
                         }
                 }
 
-                spin_lock_irqsave(&tree->lock, flags);
-                if (!state || state->end != end) {
-                        state = NULL;
-                        node = __etree_search(tree, start, NULL, NULL);
-                        if (node) {
-                                state = rb_entry(node, struct extent_state,
-                                                 rb_node);
-                                if (state->end != end ||
-                                    !(state->state & EXTENT_LOCKED))
-                                        state = NULL;
-                        }
-                        if (!state) {
-                                spin_unlock_irqrestore(&tree->lock, flags);
-                                if (uptodate)
-                                        set_extent_uptodate(tree, start, end,
-                                                            GFP_ATOMIC);
-                                unlock_extent(tree, start, end, GFP_ATOMIC);
-                                goto next_io;
-                        }
-                }
+                if (uptodate)
+                        set_extent_uptodate(tree, start, end,
+                                            GFP_ATOMIC);
+                unlock_extent(tree, start, end, GFP_ATOMIC);
 
-                cur = end;
-                while(1) {
-                        struct extent_state *clear = state;
-                        cur = state->start;
-                        node = rb_prev(&state->rb_node);
-                        if (node) {
-                                state = rb_entry(node,
-                                         struct extent_state,
-                                         rb_node);
-                        } else {
-                                state = NULL;
-                        }
-                        if (uptodate) {
-                                set_state_cb(tree, clear, EXTENT_UPTODATE);
-                                clear->state |= EXTENT_UPTODATE;
-                        }
-                        clear_state_bit(tree, clear, EXTENT_LOCKED,
-                                        1, 0);
-                        if (cur == start)
-                                break;
-                        if (cur < start) {
-                                WARN_ON(1);
-                                break;
-                        }
-                        if (!node)
-                                break;
-                }
-                /* before releasing the lock, make sure the next state
-                 * variable has the expected bits set and corresponds
-                 * to the correct offsets in the file
-                 */
-                if (state && (state->end + 1 != start ||
-                    !(state->state & EXTENT_LOCKED))) {
-                        state = NULL;
-                }
-                spin_unlock_irqrestore(&tree->lock, flags);
-next_io:
                 if (whole_page) {
                         if (uptodate) {
                                 SetPageUptodate(page);
@@ -1683,8 +1565,7 @@ static int end_bio_extent_preparewrite(struct bio *bio,
 {
         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
         struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-        struct extent_state *state = bio->bi_private;
-        struct extent_io_tree *tree = state->tree;
+        struct extent_io_tree *tree;
         u64 start;
         u64 end;
 
@@ -1695,6 +1576,8 @@ static int end_bio_extent_preparewrite(struct bio *bio,
 
         do {
                 struct page *page = bvec->bv_page;
+                tree = &BTRFS_I(page->mapping->host)->io_tree;
+
                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
                         bvec->bv_offset;
                 end = start + bvec->bv_len - 1;
@@ -1765,7 +1648,7 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num)
         BUG_ON(state->end != end);
         spin_unlock_irq(&tree->lock);
 
-        bio->bi_private = state;
+        bio->bi_private = NULL;
 
         bio_get(bio);