[Ocfs2-devel] [patch 03/15] ocfs2: call ocfs2_journal_access_di() before ocfs2_journal_dirty() in ocfs2_write_end_nolock()
Andrew Morton
akpm at linux-foundation.org
Wed Dec 17 13:33:31 PST 2014
So I now have a mess on my hands due to reordering
ocfs2-fix-journal-commit-deadlock.patch ahead of this patch.
It concerns the label "out:". Should it be placed before or after the
call to ocfs2_unlock_pages()?
My current copy of ocfs2_write_end_nolock() is below, followed by my
current version of
ocfs2-call-ocfs2_journal_access_di-before-ocfs2_journal_dirty-in-ocfs2_write_end_nolock.patch
Thanks.
int ocfs2_write_end_nolock(struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
int i, ret;
unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
struct inode *inode = mapping->host;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
struct ocfs2_write_ctxt *wc = fsdata;
struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
handle_t *handle = wc->w_handle;
struct page *tmppage;
if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
ocfs2_write_end_inline(inode, pos, len, &copied, di, wc);
goto out_write_size;
}
if (unlikely(copied < len)) {
if (!PageUptodate(wc->w_target_page))
copied = 0;
ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
start+len);
}
flush_dcache_page(wc->w_target_page);
for(i = 0; i < wc->w_num_pages; i++) {
tmppage = wc->w_pages[i];
if (tmppage == wc->w_target_page) {
from = wc->w_target_from;
to = wc->w_target_to;
BUG_ON(from > PAGE_CACHE_SIZE ||
to > PAGE_CACHE_SIZE ||
to < from);
} else {
/*
* Pages adjacent to the target (if any) imply
* a hole-filling write in which case we want
* to flush their entire range.
*/
from = 0;
to = PAGE_CACHE_SIZE;
}
if (page_has_buffers(tmppage)) {
if (ocfs2_should_order_data(inode))
ocfs2_jbd2_file_inode(wc->w_handle, inode);
block_commit_write(tmppage, from, to);
}
}
ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
OCFS2_JOURNAL_ACCESS_WRITE);
if (ret) {
copied = ret;
mlog_errno(ret);
goto out;
}
out_write_size:
pos += copied;
if (pos > i_size_read(inode)) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
}
inode->i_blocks = ocfs2_inode_sector_count(inode);
di->i_size = cpu_to_le64((u64)i_size_read(inode));
inode->i_mtime = inode->i_ctime = CURRENT_TIME;
di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
ocfs2_update_inode_fsync_trans(handle, inode, 1);
ocfs2_journal_dirty(handle, wc->w_di_bh);
/* unlock pages before dealloc since it needs acquiring j_trans_barrier
* lock, or it will cause a deadlock since journal commit threads holds
* this lock and will ask for the page lock when flushing the data.
* put it here to preserve the unlock order.
*/
ocfs2_unlock_pages(wc);
out:
ocfs2_commit_trans(osb, handle);
ocfs2_run_deallocs(osb, &wc->w_dealloc);
brelse(wc->w_di_bh);
kfree(wc);
return copied;
}
From: yangwenfang <vicky.yangwenfang at huawei.com>
Subject: ocfs2: call ocfs2_journal_access_di() before ocfs2_journal_dirty() in ocfs2_write_end_nolock()
After we call ocfs2_journal_access_di() in ocfs2_write_begin(),
jbd2_journal_restart() may also be called, in this function transaction
A's t_updates-- and obtains a new transaction B. If
jbd2_journal_commit_transaction() is happened to commit transaction A,
when t_updates==0, it will continue to complete commit and unfile buffer.
So when jbd2_journal_dirty_metadata(), the handle is pointed a new
transaction B, and the buffer head's journal head is already freed,
jh->b_transaction == NULL, jh->b_next_transaction == NULL, it returns
EINVAL, So it triggers the BUG_ON(status).
thread 1: jbd2:
ocfs2_write_begin jbd2_journal_commit_transaction
ocfs2_write_begin_nolock
ocfs2_start_trans
jbd2__journal_start(t_updates+1,
transaction A)
ocfs2_journal_access_di
ocfs2_write_cluster_by_desc
ocfs2_mark_extent_written
ocfs2_change_extent_flag
ocfs2_split_extent
ocfs2_extend_rotate_transaction
jbd2_journal_restart
(t_updates-1,transaction B) t_updates==0
__jbd2_journal_refile_buffer
ocfs2_write_end
ocfs2_write_end_nolock
ocfs2_journal_dirty
jbd2_journal_dirty_metadata(bug)
ocfs2_commit_trans
In ext4, I found that: jbd2_journal_get_write_access() called by
ext4_write_end.
ext4_write_begin
ext4_journal_start
__ext4_journal_start_sb
ext4_journal_check_start
jbd2__journal_start
ext4_write_end
ext4_mark_inode_dirty
ext4_reserve_inode_write
ext4_journal_get_write_access
jbd2_journal_get_write_access
ext4_mark_iloc_dirty
ext4_do_update_inode
ext4_handle_dirty_metadata
jbd2_journal_dirty_metadata
So I think we should put ocfs2_journal_access_di before
ocfs2_journal_dirty in the ocfs2_write_end. and it works well after my
modification.
Signed-off-by: vicky <vicky.yangwenfang at huawei.com>
Cc: Mark Fasheh <mfasheh at suse.com>
Cc: Joel Becker <jlbec at evilplan.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---
fs/ocfs2/aops.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff -puN fs/ocfs2/aops.c~ocfs2-call-ocfs2_journal_access_di-before-ocfs2_journal_dirty-in-ocfs2_write_end_nolock fs/ocfs2/aops.c
--- a/fs/ocfs2/aops.c~ocfs2-call-ocfs2_journal_access_di-before-ocfs2_journal_dirty-in-ocfs2_write_end_nolock
+++ a/fs/ocfs2/aops.c
@@ -1822,16 +1822,6 @@ try_again:
if (ret)
goto out_commit;
}
- /*
- * We don't want this to fail in ocfs2_write_end(), so do it
- * here.
- */
- ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
- OCFS2_JOURNAL_ACCESS_WRITE);
- if (ret) {
- mlog_errno(ret);
- goto out_quota;
- }
/*
* Fill our page array first. That way we've grabbed enough so
@@ -1982,7 +1972,7 @@ int ocfs2_write_end_nolock(struct addres
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
- int i;
+ int i, ret;
unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
struct inode *inode = mapping->host;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
@@ -2032,6 +2022,14 @@ int ocfs2_write_end_nolock(struct addres
}
}
+ ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
+ OCFS2_JOURNAL_ACCESS_WRITE);
+ if (ret) {
+ copied = ret;
+ mlog_errno(ret);
+ goto out;
+ }
+
out_write_size:
pos += copied;
if (pos > i_size_read(inode)) {
@@ -2053,6 +2051,7 @@ out_write_size:
*/
ocfs2_unlock_pages(wc);
+out:
ocfs2_commit_trans(osb, handle);
ocfs2_run_deallocs(osb, &wc->w_dealloc);
_
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