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 <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I2c3e8c2edf975b44a0a52a45c7564385180a5cd5
diff --git a/fs/super.c b/fs/super.c
index e6019ed..51f4320 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -459,6 +459,8 @@ 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;
}
@@ -1322,6 +1324,7 @@ 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 8bfb32e..0b7d8a9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1337,6 +1337,8 @@ extern int send_sigurg(struct fown_struct *fown);
/* sb->s_iflags to limit user namespace mounts */
#define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */
+#define SB_I_PERSB_BDI 0x00000200 /* has a per-sb bdi */
+
/* Possible states of 'frozen' field */
enum {
SB_UNFROZEN = 0, /* FS is unfrozen */
