From f17b1f9f1a5882e486aad469b9ac4cb18581707f Mon Sep 17 00:00:00 2001
From: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
Date: Thu, 7 Oct 2010 13:37:51 -0400
Subject: [PATCH] exofs: Fix double page_unlock BUG in write_begin/end
This BUG is there since the first submit of the code, but only triggered
in last Kernel. It's timing related do to the asynchronous object-creation
behaviour of exofs. (Which should be investigated farther)
The bug is obvious hence the fixed.
Signed-off-by: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
---
fs/exofs/inode.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index eb7368ebd8cdc..3eadd97324b14 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -54,6 +54,9 @@ struct page_collect {
unsigned nr_pages;
unsigned long length;
loff_t pg_first; /* keep 64bit also in 32-arches */
+ bool read_4_write; /* This means two things: that the read is sync
+ * And the pages should not be unlocked.
+ */
};
static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
@@ -71,6 +74,7 @@ static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
pcol->nr_pages = 0;
pcol->length = 0;
pcol->pg_first = -1;
+ pcol->read_4_write = false;
}
static void _pcol_reset(struct page_collect *pcol)
@@ -347,7 +351,8 @@ static int readpage_strip(void *data, struct page *page)
if (PageError(page))
ClearPageError(page);
- unlock_page(page);
+ if (!pcol->read_4_write)
+ unlock_page(page);
EXOFS_DBGMSG("readpage_strip(0x%lx, 0x%lx) empty page,"
" splitting\n", inode->i_ino, page->index);
@@ -428,6 +433,7 @@ static int _readpage(struct page *page, bool is_sync)
/* readpage_strip might call read_exec(,is_sync==false) at several
* places but not if we have a single page.
*/
+ pcol.read_4_write = is_sync;
ret = readpage_strip(&pcol, page);
if (ret) {
EXOFS_ERR("_readpage => %d\n", ret);
--
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