From 717beb96d969561cff53aad2f09547db20ee6ffd Mon Sep 17 00:00:00 2001
From: Chris Mason <clm@fb.com>
Date: Mon, 25 Jun 2018 10:03:41 -0700
Subject: [PATCH] Btrfs: fix regression in btrfs_page_mkwrite() from vm_fault_t
conversion
The vm_fault_t conversion commit introduced a ret2 variable for tracking
the integer return values from internal btrfs functions. It was
sometimes returning VM_FAULT_LOCKED for pages that were actually invalid
and had been removed from the radix. Something like this:
ret2 = btrfs_delalloc_reserve_space() // returns zero on success
lock_page(page)
if (page->mapping != inode->i_mapping)
goto out_unlock;
...
out_unlock:
if (!ret2) {
...
return VM_FAULT_LOCKED;
}
This ends up triggering this WARNING in btrfs_destroy_inode()
WARN_ON(BTRFS_I(inode)->block_rsv.size);
xfstests generic/095 was able to reliably reproduce the errors.
Since out_unlock: is only used for errors, this fix moves it below the
if (!ret2) check we use to return VM_FAULT_LOCKED for success.
Fixes: a528a2415087 (btrfs: change return type of btrfs_page_mkwrite to vm_fault_t)
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a6bf9e2ff68f6..f21f4223d03b4 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9005,13 +9005,14 @@ again:
unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
-out_unlock:
if (!ret2) {
btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, true);
sb_end_pagefault(inode->i_sb);
extent_changeset_free(data_reserved);
return VM_FAULT_LOCKED;
}
+
+out_unlock:
unlock_page(page);
out:
btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, (ret != 0));
--
2.30.2