[PATCH] exofs: clean up the correct page collection on write error

[Idan Kedar <idank@tonian.com>]

if ore_write() fails, we would unlock the pages of pcol, which is now
empty, rather than pcol_copy which owns the pages when ore_write() is
called. this means that no pages will actually be unlocked
(pcol.nr_pages == 0) and the writing process (more accurately, the
syncing process) will hang waiting for a writeback notification that
never comes.

moreover, if ore_write() fails, pcol_free() is called for pcol, whereas
pcol_copy is the object owning the ore_io_state, thus leaking the
ore_io_state.

Signed-off-by: Idan Kedar <idank@tonian.com>
---
 fs/exofs/inode.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index b561810..5106213 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -628,7 +628,7 @@ static int write_exec(struct page_collect *pcol)
 {
 	struct exofs_i_info *oi = exofs_i(pcol->inode);
 	struct ore_io_state *ios;
-	struct page_collect *pcol_copy = NULL;
+	struct page_collect *pcol_copy = NULL, *active_pcol = pcol;
 	int ret;
 
 	if (!pcol->pages)
@@ -658,6 +658,7 @@ static int write_exec(struct page_collect *pcol)
 
 	/* pages ownership was passed to pcol_copy */
 	_pcol_reset(pcol);
+	active_pcol = pcol_copy;
 
 	ret = _maybe_not_all_in_one_io(ios, pcol_copy, pcol);
 	if (unlikely(ret))
@@ -676,8 +677,8 @@ static int write_exec(struct page_collect *pcol)
 	return 0;
 
 err:
-	_unlock_pcol_pages(pcol, ret, WRITE);
-	pcol_free(pcol);
+	_unlock_pcol_pages(active_pcol, ret, WRITE);
+	pcol_free(active_pcol);
 	kfree(pcol_copy);
 
 	return ret;
-- 
1.7.6.5