1 files changed, 63 insertions, 21 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 20ddb28602a..ba41da59e31 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -690,6 +690,15 @@ static void cache_state(struct extent_state *state,
         }
 }
 
+static void uncache_state(struct extent_state **cached_ptr)
+{
+        if (cached_ptr && (*cached_ptr)) {
+                struct extent_state *state = *cached_ptr;
+                *cached_ptr = NULL;
+                free_extent_state(state);
+        }
+}
+
 /*
  * set some bits on a range in the tree.  This may require allocations or
  * sleeping, so the gfp mask is used to indicate what is allowed.
@@ -940,10 +949,10 @@ static int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
 }
 
 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
-                        gfp_t mask)
+                        struct extent_state **cached_state, gfp_t mask)
 {
-        return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
-                              NULL, mask);
+        return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0,
+                              NULL, cached_state, mask);
 }
 
 static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
@@ -1012,8 +1021,7 @@ int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
                                 mask);
 }
 
-int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
-                  gfp_t mask)
+int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
 {
         return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
                                 mask);
@@ -1735,6 +1743,9 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
 
         do {
                 struct page *page = bvec->bv_page;
+                struct extent_state *cached = NULL;
+                struct extent_state *state;
+
                 tree = &BTRFS_I(page->mapping->host)->io_tree;
 
                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
@@ -1749,9 +1760,20 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                 if (++bvec <= bvec_end)
                         prefetchw(&bvec->bv_page->flags);
 
+                spin_lock(&tree->lock);
+                state = find_first_extent_bit_state(tree, start, EXTENT_LOCKED);
+                if (state && state->start == start) {
+                        /*
+                         * take a reference on the state, unlock will drop
+                         * the ref
+                         */
+                        cache_state(state, &cached);
+                }
+                spin_unlock(&tree->lock);
+
                 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
                         ret = tree->ops->readpage_end_io_hook(page, start, end,
-                                                              NULL);
+                                                              state);
                         if (ret)
                                 uptodate = 0;
                 }
@@ -1764,15 +1786,16 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                                         test_bit(BIO_UPTODATE, &bio->bi_flags);
                                 if (err)
                                         uptodate = 0;
+                                uncache_state(&cached);
                                 continue;
                         }
                 }
 
                 if (uptodate) {
-                        set_extent_uptodate(tree, start, end,
+                        set_extent_uptodate(tree, start, end, &cached,
                                             GFP_ATOMIC);
                 }
-                unlock_extent(tree, start, end, GFP_ATOMIC);
+                unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
 
                 if (whole_page) {
                         if (uptodate) {
@@ -1811,6 +1834,7 @@ static void end_bio_extent_preparewrite(struct bio *bio, int err)
 
         do {
                 struct page *page = bvec->bv_page;
+                struct extent_state *cached = NULL;
                 tree = &BTRFS_I(page->mapping->host)->io_tree;
 
                 start = ((u64)page->index << PAGE_CACHE_SHIFT) +
@@ -1821,13 +1845,14 @@ static void end_bio_extent_preparewrite(struct bio *bio, int err)
                         prefetchw(&bvec->bv_page->flags);
 
                 if (uptodate) {
-                        set_extent_uptodate(tree, start, end, GFP_ATOMIC);
+                        set_extent_uptodate(tree, start, end, &cached,
+                                            GFP_ATOMIC);
                 } else {
                         ClearPageUptodate(page);
                         SetPageError(page);
                 }
 
-                unlock_extent(tree, start, end, GFP_ATOMIC);
+                unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
 
         } while (bvec >= bio->bi_io_vec);
 
@@ -2016,14 +2041,17 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
         while (cur <= end) {
                 if (cur >= last_byte) {
                         char *userpage;
+                        struct extent_state *cached = NULL;
+
                         iosize = PAGE_CACHE_SIZE - page_offset;
                         userpage = kmap_atomic(page, KM_USER0);
                         memset(userpage + page_offset, 0, iosize);
                         flush_dcache_page(page);
                         kunmap_atomic(userpage, KM_USER0);
                         set_extent_uptodate(tree, cur, cur + iosize - 1,
-                                            GFP_NOFS);
-                        unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
+                                            &cached, GFP_NOFS);
+                        unlock_extent_cached(tree, cur, cur + iosize - 1,
+                                             &cached, GFP_NOFS);
                         break;
                 }
                 em = get_extent(inode, page, page_offset, cur,
@@ -2063,14 +2091,17 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
                 /* we've found a hole, just zero and go on */
                 if (block_start == EXTENT_MAP_HOLE) {
                         char *userpage;
+                        struct extent_state *cached = NULL;
+
                         userpage = kmap_atomic(page, KM_USER0);
                         memset(userpage + page_offset, 0, iosize);
                         flush_dcache_page(page);
                         kunmap_atomic(userpage, KM_USER0);
 
                         set_extent_uptodate(tree, cur, cur + iosize - 1,
-                                            GFP_NOFS);
-                        unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
+                                            &cached, GFP_NOFS);
+                        unlock_extent_cached(tree, cur, cur + iosize - 1,
+                                             &cached, GFP_NOFS);
                         cur = cur + iosize;
                         page_offset += iosize;
                         continue;
@@ -2650,7 +2681,7 @@ int extent_readpages(struct extent_io_tree *tree,
                 prefetchw(&page->flags);
                 list_del(&page->lru);
                 if (!add_to_page_cache_lru(page, mapping,
-                                        page->index, GFP_KERNEL)) {
+                                        page->index, GFP_NOFS)) {
                         __extent_read_full_page(tree, page, get_extent,
                                                 &bio, 0, &bio_flags);
                 }
@@ -2789,9 +2820,12 @@ int extent_prepare_write(struct extent_io_tree *tree,
                         iocount++;
                         block_start = block_start + iosize;
                 } else {
-                        set_extent_uptodate(tree, block_start, cur_end,
+                        struct extent_state *cached = NULL;
+
+                        set_extent_uptodate(tree, block_start, cur_end, &cached,
                                             GFP_NOFS);
-                        unlock_extent(tree, block_start, cur_end, GFP_NOFS);
+                        unlock_extent_cached(tree, block_start, cur_end,
+                                             &cached, GFP_NOFS);
                         block_start = cur_end + 1;
                 }
                 page_offset = block_start & (PAGE_CACHE_SIZE - 1);
@@ -3457,7 +3491,7 @@ 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,
-                            GFP_NOFS);
+                            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))) ||
@@ -3885,6 +3919,12 @@ static void move_pages(struct page *dst_page, struct page *src_page,
         kunmap_atomic(dst_kaddr, KM_USER0);
 }
 
+static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
+{
+        unsigned long distance = (src > dst) ? src - dst : dst - src;
+        return distance < len;
+}
+
 static void copy_pages(struct page *dst_page, struct page *src_page,
                        unsigned long dst_off, unsigned long src_off,
                        unsigned long len)
@@ -3892,10 +3932,12 @@ static void copy_pages(struct page *dst_page, struct page *src_page,
         char *dst_kaddr = kmap_atomic(dst_page, KM_USER0);
         char *src_kaddr;
 
-        if (dst_page != src_page)
+        if (dst_page != src_page) {
                 src_kaddr = kmap_atomic(src_page, KM_USER1);
-        else
+        } 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);
@@ -3970,7 +4012,7 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
                        "len %lu len %lu\n", dst_offset, len, dst->len);
                 BUG_ON(1);
         }
-        if (dst_offset < src_offset) {
+        if (!areas_overlap(src_offset, dst_offset, len)) {
                 memcpy_extent_buffer(dst, dst_offset, src_offset, len);
                 return;
         }