fuse2fs: don't run fallible operations in op_init

There's no way to return an error from the op_init function and have
libfuse tear down the mount, aside from calling fuse_session_exit and
aborting the program.  Even that's not useful, because libfuse has
already daemonized us at that point, so the error messages are screamed
into a void.

Move the code that clears the VALID_FS bit to main() so that we can
abort the mount with a useful error message if that write fails.

Cc: <linux-ext4@vger.kernel.org> # v1.43
Fixes: 81cbf1ef4f5dab ("misc: add fuse2fs, a FUSE server for e2fsprogs")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>

diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index d670c5db1206f2134bb9d5cf7f68729f5676e318..c201f95e771b8580142aa2861cdffa3be708755e 100644 (file)
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -907,7 +907,6 @@ static void *op_init(struct fuse_conn_info *conn
        struct fuse_context *ctxt = fuse_get_context();
        struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
        ext2_filsys fs;
-       errcode_t err;
 
        if (ff->magic != FUSE2FS_MAGIC) {
                translate_error(global_fs, 0, EXT2_ET_BAD_MAGIC);
@@ -939,15 +938,6 @@ static void *op_init(struct fuse_conn_info *conn
        if (ff->debug)
                cfg->debug = 1;
 #endif
-       if (fs->flags & EXT2_FLAG_RW) {
-               fs->super->s_mnt_count++;
-               ext2fs_set_tstamp(fs->super, s_mtime, time(NULL));
-               fs->super->s_state &= ~EXT2_VALID_FS;
-               ext2fs_mark_super_dirty(fs);
-               err = ext2fs_flush2(fs, 0);
-               if (err)
-                       translate_error(fs, 0, err);
-       }
 
        if (ff->kernel) {
                char uuid[UUID_STR_SIZE];
@@ -4733,6 +4723,10 @@ int main(int argc, char *argv[])
                goto out;
        }
 
+       /*
+        * ext4 can't do COW of shared blocks, so if the feature is enabled,
+        * we must force ro mode.
+        */
        if (ext2fs_has_feature_shared_blocks(global_fs->super))
                fctx.ro = 1;
 
@@ -4796,6 +4790,20 @@ int main(int argc, char *argv[])
                goto out;
        }
 
+       /* Clear the valid flag so that an unclean shutdown forces a fsck */
+       if (global_fs->flags & EXT2_FLAG_RW) {
+               global_fs->super->s_mnt_count++;
+               ext2fs_set_tstamp(global_fs->super, s_mtime, time(NULL));
+               global_fs->super->s_state &= ~EXT2_VALID_FS;
+               ext2fs_mark_super_dirty(global_fs);
+               err = ext2fs_flush2(global_fs, 0);
+               if (err) {
+                       translate_error(global_fs, 0, err);
+                       ret |= 32;
+                       goto out;
+               }
+       }
+
        /* Initialize generation counter */
        get_random_bytes(&fctx.next_generation, sizeof(unsigned int));