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Commit 9b4c0ff3 authored by Jan Kara's avatar Jan Kara Committed by Tao Ma
Browse files

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.

Acked-by: default avatarMark Fasheh <mfasheh@suse.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarTao Ma <tao.ma@oracle.com>
parent b2b6ebf5

fs/ocfs2/alloc.c

+1 −1
Original line number Diff line number Diff line
@@ -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
Original line number Diff line number Diff line
@@ -783,7 +783,7 @@ 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
Original line number Diff line number Diff line
@@ -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);