On 03/08/2018 10:33 PM, David Sterba wrote:
All callers pass a valid pointer, we can remove the redundant checks.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
---
fs/btrfs/extent_io.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d00d5a59ff21..36514baa661e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2875,6 +2875,8 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
* handlers)
* XXX JDM: This needs looking at to ensure proper page locking
* return 0 on success, otherwise return error
+ *
+ * @prev_em_start: return value of previous em start value; must be valid
*/
static int __do_readpage(struct extent_io_tree *tree,
struct page *page,
@@ -2903,6 +2905,8 @@ static int __do_readpage(struct extent_io_tree *tree,
size_t blocksize = inode->i_sb->s_blocksize;
unsigned long this_bio_flag = 0;
+ ASSERT(prev_em_start);
+
mount is failing with this patch as in this stack below the
prev_em_start is NULL.
--------
static int __extent_read_full_page(struct extent_io_tree *tree,
struct page *page,
get_extent_t *get_extent,
struct bio **bio, int mirror_num,
unsigned long *bio_flags,
unsigned int read_flags)
{
::
ret = __do_readpage(tree, page, get_extent, NULL, bio, mirror_num,
bio_flags, read_flags, NULL);
----------
kernel: assertion failed: prev_em_start, file: fs/btrfs/extent_io.c,
line: 2911
kernel: ------------[ cut here ]------------
kernel: kernel BUG at fs/btrfs/ctree.h:3462!
kernel: __do_readpage+0x7f/0x7e0 [btrfs]
kernel: ? btree_fs_info+0x20/0x20 [btrfs]
kernel: ? mark_held_locks+0x65/0x80
kernel: ? _raw_spin_unlock_irq+0x29/0x40
kernel: __extent_read_full_page+0xe7/0x100 [btrfs]
kernel: ? btree_fs_info+0x20/0x20 [btrfs]
kernel: read_extent_buffer_pages+0x1af/0x2b0 [btrfs]
kernel: btree_read_extent_buffer_pages+0x4f/0xe0 [btrfs]
kernel: read_tree_block+0x31/0x60 [btrfs]
kernel: ? __raw_spin_lock_init+0x2d/0x50
kernel: open_ctree+0x19a2/0x25f0 [btrfs]
kernel: btrfs_mount_root+0x465/0x720 [btrfs]
kernel: ? __lockdep_init_map+0xb6/0x1d0
kernel: ? mount_fs+0x89/0x130
kernel: ? __init_waitqueue_head+0x36/0x50
kernel: mount_fs+0x89/0x130
kernel: vfs_kern_mount+0x69/0x160
---------
Thanks, Anand
set_page_extent_mapped(page);
end = page_end;
@@ -3012,12 +3016,11 @@ static int __do_readpage(struct extent_io_tree *tree,
* non-optimal behavior (submitting 2 bios for the same extent).
*/
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
- prev_em_start && *prev_em_start != (u64)-1 &&
+ *prev_em_start != (u64)-1 &&
*prev_em_start != em->orig_start)
force_bio_submit = true;
- if (prev_em_start)
- *prev_em_start = em->orig_start;
+ *prev_em_start = em->orig_start;
free_extent_map(em);
em = NULL;
--
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