staging/lustre/llite: deadlock taking lli_trunc_sem during file write

File write before io loop will take lli_trun_sem read semaphore to
protect osc_extent, while after generic_file_aio_write() done, it
could possible need to kill suid or sgid, which will call
ll_setattr_raw() to change the inode's attribute, and it does not
involve size.

So the ll_truc_sem write semaphore should be constrained
around ll_setattr_ost() to not come across the lli_trunc_sem read
semaphore get from the normal file write path.

Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Reviewed-on: http://review.whamcloud.com/9267
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4627
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index 7c4fd97a7fa0502684263a011e04064b1148be34..373a24f5d5d7e0402cab008db0d325d7d8f9334a 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -1449,7 +1449,6 @@ int ll_setattr_raw(struct dentry *dentry, struct iattr *attr, bool hsm_import)
                if (attr->ia_valid & ATTR_SIZE)
                        inode_dio_write_done(inode);
                mutex_unlock(&inode->i_mutex);
-               down_write(&lli->lli_trunc_sem);
        }
 
        memcpy(&op_data->op_attr, attr, sizeof(*attr));
@@ -1513,7 +1512,11 @@ int ll_setattr_raw(struct dentry *dentry, struct iattr *attr, bool hsm_import)
                 * excessive to send mtime/atime updates to OSTs when not
                 * setting times to past, but it is necessary due to possible
                 * time de-synchronization between MDT inode and OST objects */
+               if (attr->ia_valid & ATTR_SIZE)
+                       down_write(&lli->lli_trunc_sem);
                rc = ll_setattr_ost(inode, attr);
+               if (attr->ia_valid & ATTR_SIZE)
+                       up_write(&lli->lli_trunc_sem);
 out:
        if (op_data) {
                if (op_data->op_ioepoch) {
@@ -1524,7 +1527,6 @@ out:
                ll_finish_md_op_data(op_data);
        }
        if (!S_ISDIR(inode->i_mode)) {
-               up_write(&lli->lli_trunc_sem);
                mutex_lock(&inode->i_mutex);
                if ((attr->ia_valid & ATTR_SIZE) && !hsm_import)
                        inode_dio_wait(inode);