ocfs2: ip_alloc_sem should be taken in ocfs2_get_block() (3e4c56d4) · Commits · 戴 / test

ip_alloc_sem should be taken in ocfs2_get_block() when reading file in DIRECT mode to prevent concurrent access to extent tree with ocfs2_dio_end_io_write(), which may cause BUGON in the following situation: read file 'A' end_io of writing file 'A' vfs_read __vfs_read ocfs2_file_read_iter generic_file_read_iter ocfs2_direct_IO __blockdev_direct_IO do_blockdev_direct_IO do_direct_IO get_more_blocks ocfs2_get_block ocfs2_extent_map_get_blocks ocfs2_get_clusters ocfs2_get_clusters_nocache() ocfs2_search_extent_list return the index of record which contains the v_cluster, that is v_cluster > rec[i]->e_cpos. ocfs2_dio_end_io ocfs2_dio_end_io_write down_write(&oi->ip_alloc_sem); ocfs2_mark_extent_written ocfs2_change_extent_flag ocfs2_split_extent ... --> modify the rec[i]->e_cpos, resulting in v_cluster < rec[i]->e_cpos. BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos)) [alex.chen@huawei.com: v3] Link: http://lkml.kernel.org/r/59EF3614.6050008@huawei.com Link: http://lkml.kernel.org/r/59EF3614.6050008@huawei.com Fixes: ("ocfs2: fix sparse file & data ordering issue in direct io") Signed-off-by:

Alex Chen <alex.chen@huawei.com> Reviewed-by:

Jun Piao <piaojun@huawei.com> Reviewed-by:

Joseph Qi <jiangqi903@gmail.com> Reviewed-by:

Gang He <ghe@suse.com> Acked-by:

Changwei Ge <ge.changwei@h3c.com> Cc: Mark Fasheh <mfasheh@versity.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/aops.c

+18 −8

Original line number	Diff line number	Diff line
		@@ -134,6 +134,19 @@ bail:
		return err;
		}

		static int ocfs2_lock_get_block(struct inode *inode, sector_t iblock,
		struct buffer_head *bh_result, int create)
		{
		int ret = 0;
		struct ocfs2_inode_info *oi = OCFS2_I(inode);

		down_read(&oi->ip_alloc_sem);
		ret = ocfs2_get_block(inode, iblock, bh_result, create);
		up_read(&oi->ip_alloc_sem);

		return ret;
		}

		int ocfs2_get_block(struct inode *inode, sector_t iblock,
		struct buffer_head *bh_result, int create)
		{
		@@ -2128,7 +2141,7 @@ static void ocfs2_dio_free_write_ctx(struct inode *inode,
		* called like this: dio->get_blocks(dio->inode, fs_startblk,
		* fs_count, map_bh, dio->rw == WRITE);
		*/
		static int ocfs2_dio_get_block(struct inode *inode, sector_t iblock,
		static int ocfs2_dio_wr_get_block(struct inode *inode, sector_t iblock,
		struct buffer_head *bh_result, int create)
		{
		struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
		@@ -2154,12 +2167,9 @@ static int ocfs2_dio_get_block(struct inode *inode, sector_t iblock,
		* while file size will be changed.
		*/
		if (pos + total_len <= i_size_read(inode)) {
		down_read(&oi->ip_alloc_sem);
		/* This is the fast path for re-write. */
		ret = ocfs2_get_block(inode, iblock, bh_result, create);

		up_read(&oi->ip_alloc_sem);

		/* This is the fast path for re-write. */
		ret = ocfs2_lock_get_block(inode, iblock, bh_result, create);
		if (buffer_mapped(bh_result) &&
		!buffer_new(bh_result) &&
		ret == 0)
		@@ -2424,9 +2434,9 @@ static ssize_t ocfs2_direct_IO(struct kiocb iocb, struct iov_iter iter)
		return 0;

		if (iov_iter_rw(iter) == READ)
		get_block = ocfs2_get_block;
		get_block = ocfs2_lock_get_block;
		else
		get_block = ocfs2_dio_get_block;
		get_block = ocfs2_dio_wr_get_block;

		return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
		iter, get_block,

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