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-rw-r--r--fs/btrfs/inode.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 45cf03ee1bc..2e25d698bab 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4156,11 +4156,6 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
return -EINVAL;
}
-static sector_t btrfs_bmap(struct address_space *mapping, sector_t iblock)
-{
- return extent_bmap(mapping, iblock, btrfs_get_extent);
-}
-
int btrfs_readpage(struct file *file, struct page *page)
{
struct extent_io_tree *tree;
@@ -4985,13 +4980,24 @@ static struct extent_io_ops btrfs_extent_io_ops = {
.clear_bit_hook = btrfs_clear_bit_hook,
};
+/*
+ * btrfs doesn't support the bmap operation because swapfiles
+ * use bmap to make a mapping of extents in the file. They assume
+ * these extents won't change over the life of the file and they
+ * use the bmap result to do IO directly to the drive.
+ *
+ * the btrfs bmap call would return logical addresses that aren't
+ * suitable for IO and they also will change frequently as COW
+ * operations happen. So, swapfile + btrfs == corruption.
+ *
+ * For now we're avoiding this by dropping bmap.
+ */
static struct address_space_operations btrfs_aops = {
.readpage = btrfs_readpage,
.writepage = btrfs_writepage,
.writepages = btrfs_writepages,
.readpages = btrfs_readpages,
.sync_page = block_sync_page,
- .bmap = btrfs_bmap,
.direct_IO = btrfs_direct_IO,
.invalidatepage = btrfs_invalidatepage,
.releasepage = btrfs_releasepage,