The 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
ocfs2_get_clusters_nocache()->BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos))
Signed-off-by: Alex Chen <alex.c...@huawei.com>
Reviewed-by: Jun Piao <piao...@huawei.com>
---
fs/ocfs2/aops.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 88a31e9..5cb939f 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -134,6 +134,19 @@ static int ocfs2_symlink_get_block(struct inode *inode,
sector_t iblock,
return err;
}
+static int ocfs2_get_block_lock(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ int ret;
+ 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)
{
@@ -2154,12 +2167,8 @@ 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);
-
+ ret = ocfs2_get_block_lock(inode, iblock, bh_result, create);
if (buffer_mapped(bh_result) &&
!buffer_new(bh_result) &&
ret == 0)
@@ -2424,7 +2433,7 @@ 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_get_block_lock;
else
get_block = ocfs2_dio_get_block;
-- 1.9.5.msysgit.1
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