bfs: Fix data integrity writeout issues

BFS could fail to properly write out inode on fsync(2) due to races with
WB_SYNC_NONE writeback. Several racing fsyncs could also result in some
fsync returning earlier than all metadata buffers were properly
persisted.

Fix all these issues by using new .sync_inode_metadata method which
makes sure all inode related metadata is written to disk during any
WB_SYNC_ALL writeback.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260727104923.3828017-35-jack@suse.cz
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index 5b40ab09a796defdfca0489a88f418c97849d110..9b37ec4bd89a8ceef733281059ec665b7bae345f 100644 (file)
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -68,17 +68,10 @@ static int bfs_readdir(struct file *f, struct dir_context *ctx)
        return 0;
 }
 
-static int bfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
-{
-       return mmb_fsync(file,
-                       &BFS_I(file->f_mapping->host)->i_metadata_bhs,
-                       start, end, datasync);
-}
-
 const struct file_operations bfs_dir_operations = {
        .read           = generic_read_dir,
        .iterate_shared = bfs_readdir,
-       .fsync          = bfs_fsync,
+       .fsync          = simple_fsync,
        .llseek         = generic_file_llseek,
 };
 

diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index e41efdd35db9ef167845f9b1b4839921880f2052..06e3a848b4efd88e3de675dc2fdf5b88d3e297fd 100644 (file)
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -136,7 +136,6 @@ static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
        unsigned long i_sblock;
        struct bfs_inode *di;
        struct buffer_head *bh;
-       int err = 0;
 
        dprintf("ino=%08x\n", ino);
 
@@ -165,13 +164,31 @@ static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
        di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
 
        mark_buffer_dirty(bh);
-       if (wbc->sync_mode == WB_SYNC_ALL) {
-               sync_dirty_buffer(bh);
-               if (buffer_req(bh) && !buffer_uptodate(bh))
-                       err = -EIO;
-       }
        brelse(bh);
        mutex_unlock(&info->bfs_lock);
+       set_inode_metadata_writeback(inode);
+       return 0;
+}
+
+static int bfs_sync_inode_metadata(struct inode *inode,
+                                  struct writeback_control *wbc)
+{
+       int err = 0;
+       struct bfs_inode *di;
+       struct buffer_head *bh;
+
+       di = find_inode(inode->i_sb, (u16)inode->i_ino, &bh);
+       if (IS_ERR(di))
+               return PTR_ERR(di);
+
+       sync_dirty_buffer(bh);
+       if (buffer_write_io_error(bh)) {
+               err = -EIO;
+               goto out;
+       }
+       err = mmb_sync(&BFS_I(inode)->i_metadata_bhs);
+out:
+       brelse(bh);
        return err;
 }
 
@@ -302,6 +319,7 @@ static const struct super_operations bfs_sops = {
        .alloc_inode    = bfs_alloc_inode,
        .free_inode     = bfs_free_inode,
        .write_inode    = bfs_write_inode,
+       .sync_inode_metadata = bfs_sync_inode_metadata,
        .evict_inode    = bfs_evict_inode,
        .put_super      = bfs_put_super,
        .statfs         = bfs_statfs,