[PATCH v2 8/8] Btrfs: extent_write_locked_range() should attach inode->i_wb

Tejun Heo
2019-06-14T15:33:05Z

extent_write_locked_range() is used when we're falling back to buffered
IO from inside of compression. It allocates its own wbc and should
associate it with the inode's i_wb to make sure the IO goes down from
the correct cgroup.

Also, export the needed symbols from fs-writeback.c.

Signed-off-by: Chris Mason <clm@fb.com>
Build-Breakage-Reported-by: kbuild test robot <lkp@intel.com>
---
v2: Module build fix.

fs/btrfs/extent_io.c | 10 ++++++----
fs/fs-writeback.c | 3 +++
2 files changed, 9 insertions(+), 4 deletions(-)

--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4178,6 +4178,7 @@ int extent_write_locked_range(struct ino
.no_wbc_acct = 1,
};

+ wbc_attach_fdatawrite_inode(&wbc_writepages, inode);
while (start <= end) {
page = find_get_page(mapping, start >> PAGE_SHIFT);
if (clear_page_dirty_for_io(page))
@@ -4192,11 +4193,12 @@ int extent_write_locked_range(struct ino
}

ASSERT(ret <= 0);
- if (ret < 0) {
+ if (ret == 0)
+ ret = flush_write_bio(&epd);
+ else
end_write_bio(&epd, ret);
- return ret;
- }
- ret = flush_write_bio(&epd);
+
+ wbc_detach_inode(&wbc_writepages);
return ret;
}

--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -270,6 +270,7 @@ void __inode_attach_wb(struct inode *ino
if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
wb_put(wb);
}
+EXPORT_SYMBOL_GPL(__inode_attach_wb);

/**
* locked_inode_to_wb_and_lock_list - determine a locked inode's wb and lock it
@@ -582,6 +583,7 @@ void wbc_attach_and_unlock_inode(struct
if (unlikely(wb_dying(wbc->wb)))
inode_switch_wbs(inode, wbc->wb_id);
}
+EXPORT_SYMBOL_GPL(wbc_attach_and_unlock_inode);

/**
* wbc_detach_inode - disassociate wbc from inode and perform foreign detection
@@ -701,6 +703,7 @@ void wbc_detach_inode(struct writeback_c
wb_put(wbc->wb);
wbc->wb = NULL;
}
+EXPORT_SYMBOL_GPL(wbc_detach_inode);

/**
* wbc_account_io - account IO issued during writeback