Skip to contentSkip to conversation

ocfs2: Fix deadlock when allocating page

PATCH New Jan Kara 3 participants 3 messages Aug 24, 2010 OCFS2

lore
Share & tools
lore

Jan Kara

author
#0 lore raw

PATCH 1/1 ocfs2: Fix deadlock when allocating page

We cannot call grab_cache_page() when holding filesystem locks or with a transaction started as grab_cache_page() calls page allocation with GFP_KERNEL flag and thus page reclaim can recurse back into the filesystem causing deadlocks or various assertion failures. We have to use find_or_create_page() instead and pass it GFP_NOFS as we do with other allocations.

Signed-off-by Jan Kara <[email protected]>
---
 fs/ocfs2/alloc.c        |    2 +-
 fs/ocfs2/file.c         |    2 +-
 fs/ocfs2/refcounttree.c |    5 +++--
 3 files changed, 5 insertions(+), 4 deletions(-)
fs/ocfs2/alloc.c +1 -1
index 215e12c..592fae5 100644
@@ -6672,7 +6672,7 @@ int ocfs2_grab_pages(struct inode *inode, loff_t start, loff_t end,
 	last_page_bytes = PAGE_ALIGN(end);
 	index = start >> PAGE_CACHE_SHIFT;
 	do {
-		pages[numpages] = grab_cache_page(mapping, index);
+		pages[numpages] = find_or_create_page(mapping, index, GFP_NOFS);
 		if (!pages[numpages]) {
 			ret = -ENOMEM;
 			mlog_errno(ret);
fs/ocfs2/file.c +1 -1
index 81296b4..b28cce8 100644
@@ -774,7 +774,7 @@ static int ocfs2_write_zero_page(struct inode *inode, u64 abs_from,
 	BUG_ON(abs_to > (((u64)index + 1) << PAGE_CACHE_SHIFT));
 	BUG_ON(abs_from & (inode->i_blkbits - 1));
 
-	page = grab_cache_page(mapping, index);
+	page = find_or_create_page(mapping, index, GFP_NOFS);
 	if (!page) {
 		ret = -ENOMEM;
 		mlog_errno(ret);
fs/ocfs2/refcounttree.c +3 -2
index 73a11cc..0afeda8 100644
@@ -2960,7 +2960,7 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
 		if (map_end & (PAGE_CACHE_SIZE - 1))
 			to = map_end & (PAGE_CACHE_SIZE - 1);
 
-		page = grab_cache_page(mapping, page_index);
+		page = find_or_create_page(mapping, page_index, GFP_NOFS);
 
 		/*
 		 * In case PAGE_CACHE_SIZE <= CLUSTER_SIZE, This page

@@ -3179,7 +3179,8 @@ static int ocfs2_cow_sync_writeback(struct super_block *sb,
 		if (map_end > end)
 			map_end = end;
 
-		page = grab_cache_page(context->inode->i_mapping, page_index);
+		page = find_or_create_page(context->inode->i_mapping,
+					   page_index, GFP_NOFS);
 		BUG_ON(!page);
 
 		wait_on_page_writeback(page);
Signature · 1 line
1.6.4.2
#1 lore raw

PATCH 1/1 ocfs2: Fix deadlock when allocating page

Thanks. I think we have few open bugzillas for this issue.

Quoted 71 lines · Jan Kara

We cannot call grab_cache_page() when holding filesystem locks or with a transaction started as grab_cache_page() calls page allocation with GFP_KERNEL flag and thus page reclaim can recurse back into the filesystem causing deadlocks or various assertion failures. We have to use find_or_create_page() instead and pass it GFP_NOFS as we do with other allocations.

Signed-off-by Jan Kara <[email protected]>

---

fs/ocfs2/alloc.c        |    2 +-
fs/ocfs2/file.c         |    2 +-
fs/ocfs2/refcounttree.c |    5 +++--
3 files changed, 5 insertions(+), 4 deletions(-)
fs/ocfs2/alloc.c +1 -1
index 215e12c..592fae5 100644
@@ -6672,7 +6672,7 @@ int ocfs2_grab_pages(struct inode *inode, loff_t start, loff_t end,
   last_page_bytes = PAGE_ALIGN(end);
   index = start >> PAGE_CACHE_SHIFT;
   do {
-        pages[numpages] = grab_cache_page(mapping, index);
+        pages[numpages] = find_or_create_page(mapping, index, GFP_NOFS);
       if (!pages[numpages]) {
           ret = -ENOMEM;
           mlog_errno(ret);
fs/ocfs2/file.c +1 -1
index 81296b4..b28cce8 100644
@@ -774,7 +774,7 @@ static int ocfs2_write_zero_page(struct inode *inode, u64 abs_from,
   BUG_ON(abs_to > (((u64)index + 1) << PAGE_CACHE_SHIFT));
   BUG_ON(abs_from & (inode->i_blkbits - 1));
 
-    page = grab_cache_page(mapping, index);
+    page = find_or_create_page(mapping, index, GFP_NOFS);
   if (!page) {
       ret = -ENOMEM;
       mlog_errno(ret);
fs/ocfs2/refcounttree.c +3 -2
index 73a11cc..0afeda8 100644
@@ -2960,7 +2960,7 @@ static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
       if (map_end & (PAGE_CACHE_SIZE - 1))
           to = map_end & (PAGE_CACHE_SIZE - 1);
 
-        page = grab_cache_page(mapping, page_index);
+        page = find_or_create_page(mapping, page_index, GFP_NOFS);
 
       /*
        * In case PAGE_CACHE_SIZE <= CLUSTER_SIZE, This page

@@ -3179,7 +3179,8 @@ static int ocfs2_cow_sync_writeback(struct super_block *sb,
       if (map_end > end)
           map_end = end;
 
-        page = grab_cache_page(context->inode->i_mapping, page_index);
+        page = find_or_create_page(context->inode->i_mapping,
+                       page_index, GFP_NOFS);
       BUG_ON(!page);
 
       wait_on_page_writeback(page);
Signature · 7 lines
1.6.4.2


_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel at oss.oracle.com
http://oss.oracle.com/mailman/listinfo/ocfs2-devel
#2 lore raw

PATCH 1/1 ocfs2: Fix deadlock when allocating page

In reply to Jan Kara
Quoted 8 lines · Jan Kara

We cannot call grab_cache_page() when holding filesystem locks or with a transaction started as grab_cache_page() calls page allocation with GFP_KERNEL flag and thus page reclaim can recurse back into the filesystem causing deadlocks or various assertion failures. We have to use find_or_create_page() instead and pass it GFP_NOFS as we do with other allocations.

Signed-off-by Jan Kara <[email protected]>
Acked-by Mark Fasheh <[email protected]>
	--Mark

--
Mark Fasheh