From: Jan Kara <j...@suse.cz>
When DAX is enabled, it uses i_mmap_mutex as a protection against
truncate during page fault. This inevitably forces i_mmap_mutex to rank
outside of a transaction start and thus we have to avoid calling
pagecache purging operations when transaction is started.
Signed-off-by: Jan Kara <j...@suse.cz>
Signed-off-by: Matthew Wilcox <matthew.r.wil...@intel.com>
---
fs/ext4/inode.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 8a06473..494a864 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3631,13 +3631,19 @@ int ext4_punch_hole(struct inode *inode, loff_t offset,
loff_t length)
if (IS_SYNC(inode))
ext4_handle_sync(handle);
- /* Now release the pages again to reduce race window */
+ inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+
+ /*
+ * Now release the pages again to reduce race window. This has to happen
+ * outside of a transaction to avoid lock inversion on i_mmap_mutex
+ * when DAX is enabled.
+ */
if (last_block_offset > first_block_offset)
truncate_pagecache_range(inode, first_block_offset,
last_block_offset);
-
- inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
- ext4_mark_inode_dirty(handle, inode);
+ goto out_dio;
out_stop:
ext4_journal_stop(handle);
out_dio:
--
2.0.1
--
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