From 0b3ea0926afb8dde70cfab00316ae0a70b93a7cc Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 5 Nov 2021 13:36:58 -0700 Subject: [PATCH] fs: explicitly unregister per-superblock BDIs Add a new SB_I_ flag to mark superblocks that have an ephemeral bdi associated with them, and unregister it when the superblock is shut down. Link: https://lkml.kernel.org/r/20211021124441.668816-4-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Cc: Miquel Raynal Cc: Richard Weinberger Cc: Vignesh Raghavendra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/super.c | 3 +++ include/linux/fs.h | 1 + 2 files changed, 4 insertions(+) diff --git a/fs/super.c b/fs/super.c index bcef3a6f4c4b5..3bfc0f8fbd5bc 100644 --- a/fs/super.c +++ b/fs/super.c @@ -476,6 +476,8 @@ void generic_shutdown_super(struct super_block *sb) spin_unlock(&sb_lock); up_write(&sb->s_umount); if (sb->s_bdi != &noop_backing_dev_info) { + if (sb->s_iflags & SB_I_PERSB_BDI) + bdi_unregister(sb->s_bdi); bdi_put(sb->s_bdi); sb->s_bdi = &noop_backing_dev_info; } @@ -1562,6 +1564,7 @@ int super_setup_bdi_name(struct super_block *sb, char *fmt, ...) } WARN_ON(sb->s_bdi != &noop_backing_dev_info); sb->s_bdi = bdi; + sb->s_iflags |= SB_I_PERSB_BDI; return 0; } diff --git a/include/linux/fs.h b/include/linux/fs.h index e7a633353fd20..226de651f52e6 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1443,6 +1443,7 @@ extern int send_sigurg(struct fown_struct *fown); #define SB_I_UNTRUSTED_MOUNTER 0x00000040 #define SB_I_SKIP_SYNC 0x00000100 /* Skip superblock at global sync */ +#define SB_I_PERSB_BDI 0x00000200 /* has a per-sb bdi */ /* Possible states of 'frozen' field */ enum {