btrfs: Introduce extent_read_full_page_nolock()

[karo-tx-linux.git] / fs / btrfs / extent_io.c

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a8d662b31830499ff9fad97ad8f99cd787711d4c..df6e6c27782eba45c24a884e9922e450905b551c 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2764,11 +2764,12 @@ static int __do_readpage(struct extent_io_tree *tree,
        struct block_device *bdev;
        int ret;
        int nr = 0;
+       int parent_locked = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
        size_t pg_offset = 0;
        size_t iosize;
        size_t disk_io_size;
        size_t blocksize = inode->i_sb->s_blocksize;
-       unsigned long this_bio_flag = 0;
+       unsigned long this_bio_flag = *bio_flags & EXTENT_BIO_PARENT_LOCKED;
 
        set_page_extent_mapped(page);
 
@@ -2807,15 +2808,18 @@ static int __do_readpage(struct extent_io_tree *tree,
                        kunmap_atomic(userpage);
                        set_extent_uptodate(tree, cur, cur + iosize - 1,
                                            &cached, GFP_NOFS);
-                       unlock_extent_cached(tree, cur, cur + iosize - 1,
-                                            &cached, GFP_NOFS);
+                       if (!parent_locked)
+                               unlock_extent_cached(tree, cur,
+                                                    cur + iosize - 1,
+                                                    &cached, GFP_NOFS);
                        break;
                }
                em = __get_extent_map(inode, page, pg_offset, cur,
                                      end - cur + 1, get_extent, em_cached);
                if (IS_ERR_OR_NULL(em)) {
                        SetPageError(page);
-                       unlock_extent(tree, cur, end);
+                       if (!parent_locked)
+                               unlock_extent(tree, cur, end);
                        break;
                }
                extent_offset = cur - em->start;
@@ -2823,7 +2827,7 @@ static int __do_readpage(struct extent_io_tree *tree,
                BUG_ON(end < cur);
 
                if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
-                       this_bio_flag = EXTENT_BIO_COMPRESSED;
+                       this_bio_flag |= EXTENT_BIO_COMPRESSED;
                        extent_set_compress_type(&this_bio_flag,
                                                 em->compress_type);
                }
@@ -2867,7 +2871,8 @@ static int __do_readpage(struct extent_io_tree *tree,
                if (test_range_bit(tree, cur, cur_end,
                                   EXTENT_UPTODATE, 1, NULL)) {
                        check_page_uptodate(tree, page);
-                       unlock_extent(tree, cur, cur + iosize - 1);
+                       if (!parent_locked)
+                               unlock_extent(tree, cur, cur + iosize - 1);
                        cur = cur + iosize;
                        pg_offset += iosize;
                        continue;
@@ -2877,7 +2882,8 @@ static int __do_readpage(struct extent_io_tree *tree,
                 */
                if (block_start == EXTENT_MAP_INLINE) {
                        SetPageError(page);
-                       unlock_extent(tree, cur, cur + iosize - 1);
+                       if (!parent_locked)
+                               unlock_extent(tree, cur, cur + iosize - 1);
                        cur = cur + iosize;
                        pg_offset += iosize;
                        continue;
@@ -2895,7 +2901,8 @@ static int __do_readpage(struct extent_io_tree *tree,
                        *bio_flags = this_bio_flag;
                } else {
                        SetPageError(page);
-                       unlock_extent(tree, cur, cur + iosize - 1);
+                       if (!parent_locked)
+                               unlock_extent(tree, cur, cur + iosize - 1);
                }
                cur = cur + iosize;
                pg_offset += iosize;
@@ -3021,6 +3028,20 @@ int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
        return ret;
 }
 
+int extent_read_full_page_nolock(struct extent_io_tree *tree, struct page *page,
+                                get_extent_t *get_extent, int mirror_num)
+{
+       struct bio *bio = NULL;
+       unsigned long bio_flags = EXTENT_BIO_PARENT_LOCKED;
+       int ret;
+
+       ret = __do_readpage(tree, page, get_extent, NULL, &bio, mirror_num,
+                                     &bio_flags, READ);
+       if (bio)
+               ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
+       return ret;
+}
+
 static noinline void update_nr_written(struct page *page,
                                      struct writeback_control *wbc,
                                      unsigned long nr_written)