diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 81e086d8aa57..5581122bd2c0 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -52,8 +52,6 @@ struct wb_writeback_work { #define CREATE_TRACE_POINTS #include -#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) - /* * We don't actually have pdflush, but this one is exported though /proc... */ @@ -71,6 +69,27 @@ int writeback_in_progress(struct backing_dev_info *bdi) return test_bit(BDI_writeback_running, &bdi->state); } +static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info; + + /* + * For inodes on standard filesystems, we use superblock's bdi. For + * inodes on virtual filesystems, we want to use inode mapping's bdi + * because they can possibly point to something useful (think about + * block_dev filesystem). + */ + if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) { + /* Some device inodes could play dirty tricks. Catch them... */ + WARN(bdi != sb->s_bdi && bdi_cap_writeback_dirty(bdi), + "Dirtiable inode bdi %s != sb bdi %s\n", + bdi->name, sb->s_bdi->name); + return sb->s_bdi; + } + return bdi; +} + static void bdi_queue_work(struct backing_dev_info *bdi, struct wb_writeback_work *work) {