bcachefs: Fix a dio bug

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index ad06db069fcf33e9535f26b71365a568701f1c09..c9a136797aa77a80fcfcd1198c57de72478ed353 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -57,7 +57,7 @@ struct bch_writepage_io {
 struct dio_write {
        struct closure                  cl;
        struct kiocb                    *req;
-       struct task_struct              *task;
+       struct mm_struct                *mm;
        unsigned                        loop:1,
                                        sync:1,
                                        free_iov:1;
@@ -1775,6 +1775,7 @@ static void bch2_dio_write_loop_async(struct closure *);
 
 static long bch2_dio_write_loop(struct dio_write *dio)
 {
+       bool kthread = (current->flags & PF_KTHREAD) != 0;
        struct kiocb *req = dio->req;
        struct address_space *mapping = req->ki_filp->f_mapping;
        struct bch_inode_info *inode = dio->iop.inode;
@@ -1797,16 +1798,16 @@ static long bch2_dio_write_loop(struct dio_write *dio)
                goto err;
 
        while (1) {
-               if (current != dio->task)
-                       kthread_use_mm(dio->task->mm);
+               if (kthread)
+                       kthread_use_mm(dio->mm);
                BUG_ON(current->faults_disabled_mapping);
                current->faults_disabled_mapping = mapping;
 
                ret = bio_iov_iter_get_pages(bio, &dio->iter);
 
                current->faults_disabled_mapping = NULL;
-               if (current != dio->task)
-                       kthread_unuse_mm(dio->task->mm);
+               if (kthread)
+                       kthread_unuse_mm(dio->mm);
 
                if (unlikely(ret < 0))
                        goto err;
@@ -1906,7 +1907,7 @@ ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
        dio = container_of(bio, struct dio_write, iop.op.wbio.bio);
        closure_init(&dio->cl, NULL);
        dio->req                = req;
-       dio->task               = current;
+       dio->mm                 = current->mm;
        dio->loop               = false;
        dio->sync               = is_sync_kiocb(req) ||
                offset + iter->count > inode->v.i_size;
@@ -1914,7 +1915,7 @@ ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
        dio->quota_res.sectors  = 0;
        dio->iter               = *iter;
        bch2_fswrite_op_init(&dio->iop, c, inode, io_opts(c, inode), true);
-       dio->iop.op.write_point = writepoint_hashed((unsigned long) dio->task);
+       dio->iop.op.write_point = writepoint_hashed((unsigned long) current);
        dio->iop.op.flags |= BCH_WRITE_NOPUT_RESERVATION;
 
        if ((req->ki_flags & IOCB_DSYNC) &&