Btrfs: avoid returning -ENOMEM in convert_extent_bit() too early

[deliverable/linux.git] / fs / btrfs / extent_io.c

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index bf3f424e0013c17d3a47047e5c7301abba93bfac..654ed3de005461a5f1829a5d432401a9035bb1fa 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -796,17 +796,25 @@ static void set_state_bits(struct extent_io_tree *tree,
        state->state |= bits_to_set;
 }
 
-static void cache_state(struct extent_state *state,
-                       struct extent_state **cached_ptr)
+static void cache_state_if_flags(struct extent_state *state,
+                                struct extent_state **cached_ptr,
+                                const u64 flags)
 {
        if (cached_ptr && !(*cached_ptr)) {
-               if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
+               if (!flags || (state->state & flags)) {
                        *cached_ptr = state;
                        atomic_inc(&state->refs);
                }
        }
 }
 
+static void cache_state(struct extent_state *state,
+                       struct extent_state **cached_ptr)
+{
+       return cache_state_if_flags(state, cached_ptr,
+                                   EXTENT_IOBITS | EXTENT_BOUNDARY);
+}
+
 /*
  * 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.
@@ -1058,13 +1066,21 @@ int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
        int err = 0;
        u64 last_start;
        u64 last_end;
+       bool first_iteration = true;
 
        btrfs_debug_check_extent_io_range(tree, start, end);
 
 again:
        if (!prealloc && (mask & __GFP_WAIT)) {
+               /*
+                * Best effort, don't worry if extent state allocation fails
+                * here for the first iteration. We might have a cached state
+                * that matches exactly the target range, in which case no
+                * extent state allocations are needed. We'll only know this
+                * after locking the tree.
+                */
                prealloc = alloc_extent_state(mask);
-               if (!prealloc)
+               if (!prealloc && !first_iteration)
                        return -ENOMEM;
        }
 
@@ -1234,6 +1250,7 @@ search_again:
        spin_unlock(&tree->lock);
        if (mask & __GFP_WAIT)
                cond_resched();
+       first_iteration = false;
        goto again;
 }
 
@@ -1482,7 +1499,7 @@ int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
        state = find_first_extent_bit_state(tree, start, bits);
 got_it:
        if (state) {
-               cache_state(state, cached_state);
+               cache_state_if_flags(state, cached_state, 0);
                *start_ret = state->start;
                *end_ret = state->end;
                ret = 0;
@@ -1746,6 +1763,9 @@ int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
        if (page_ops == 0)
                return 0;
 
+       if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
+               mapping_set_error(inode->i_mapping, -EIO);
+
        while (nr_pages > 0) {
                ret = find_get_pages_contig(inode->i_mapping, index,
                                     min_t(unsigned long,
@@ -1763,6 +1783,8 @@ int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
                                clear_page_dirty_for_io(pages[i]);
                        if (page_ops & PAGE_SET_WRITEBACK)
                                set_page_writeback(pages[i]);
+                       if (page_ops & PAGE_SET_ERROR)
+                               SetPageError(pages[i]);
                        if (page_ops & PAGE_END_WRITEBACK)
                                end_page_writeback(pages[i]);
                        if (page_ops & PAGE_UNLOCK)