ocfs2: Wrap access of directory allocations with ip_alloc_sem.
OCFS2_I(inode)->ip_alloc_sem is a read-write semaphore protecting
local concurrent access of ocfs2 inodes. However, ocfs2 directories were
not taking the semaphore while they accessed or modified the allocation
tree.
ocfs2_extend_dir() needs to take the semaphore in a write mode when it
adds to the allocation. All other directory users get there via
ocfs2_bread(), which takes the semaphore in read mode.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 67e6866..c441ef1 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -403,7 +403,7 @@
struct buffer_head **new_de_bh)
{
int status = 0;
- int credits, num_free_extents;
+ int credits, num_free_extents, drop_alloc_sem = 0;
loff_t dir_i_size;
struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
struct ocfs2_alloc_context *data_ac = NULL;
@@ -452,6 +452,9 @@
credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
}
+ down_write(&OCFS2_I(dir)->ip_alloc_sem);
+ drop_alloc_sem = 1;
+
handle = ocfs2_start_trans(osb, credits);
if (IS_ERR(handle)) {
status = PTR_ERR(handle);
@@ -497,6 +500,8 @@
*new_de_bh = new_bh;
get_bh(*new_de_bh);
bail:
+ if (drop_alloc_sem)
+ up_write(&OCFS2_I(dir)->ip_alloc_sem);
if (handle)
ocfs2_commit_trans(osb, handle);