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authoralex chen <alex.chen@huawei.com>2017-11-15 17:31:44 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-15 18:21:01 -0800
commit3e4c56d41eef5595035872a2ec5a483f42e8917f (patch)
treef050c8e277b91c7bbc9e53986017c67eba1c6e3e
parent28f5a8a7c033cbf3e32277f4cc9c6afd74f05300 (diff)
downloadlinux-3e4c56d41eef5595035872a2ec5a483f42e8917f.tar.bz2
ocfs2: ip_alloc_sem should be taken in ocfs2_get_block()
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: c15471f79506 ("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>
-rw-r--r--fs/ocfs2/aops.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 88a31e9340a0..d1516327b787 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -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,