From 144214537370b4f133a735446ebe86e90cfb2501 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Fri, 2 Apr 2010 09:46:55 +0200 Subject: backing-dev: Handle class_create() failure I hit this when we had a bug in IDR for a few days. Basically sysfs would fail to create new inodes since it uses an IDR and therefore class_create would fail. While we are unlikely to see this fail we may as well handle it instead of oopsing. Signed-off-by: Anton Blanchard Signed-off-by: Jens Axboe --- mm/backing-dev.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm/backing-dev.c') diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 0e8ca034770..f13e067e146 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -227,6 +227,9 @@ static struct device_attribute bdi_dev_attrs[] = { static __init int bdi_class_init(void) { bdi_class = class_create(THIS_MODULE, "bdi"); + if (IS_ERR(bdi_class)) + return PTR_ERR(bdi_class); + bdi_class->dev_attrs = bdi_dev_attrs; bdi_debug_init(); return 0; -- cgit v1.2.3-70-g09d2 From c3c532061e46156e8aab1268f38d66cfb63aeb2d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 22 Apr 2010 11:37:01 +0200 Subject: bdi: add helper function for doing init and register of a bdi for a file system Pretty trivial helper, just sets up the bdi and registers it. An atomic sequence count is used to ensure that the registered sysfs names are unique. Signed-off-by: Jens Axboe --- include/linux/backing-dev.h | 1 + mm/backing-dev.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) (limited to 'mm/backing-dev.c') diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index fcbc26af00e..e19c677f219 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -101,6 +101,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent, const char *fmt, ...); int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); void bdi_unregister(struct backing_dev_info *bdi); +int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int); void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, long nr_pages); int bdi_writeback_task(struct bdi_writeback *wb); diff --git a/mm/backing-dev.c b/mm/backing-dev.c index f13e067e146..dbda4707f59 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -11,6 +11,8 @@ #include #include +static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); + void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) { } @@ -715,6 +717,33 @@ void bdi_destroy(struct backing_dev_info *bdi) } EXPORT_SYMBOL(bdi_destroy); +/* + * For use from filesystems to quickly init and register a bdi associated + * with dirty writeback + */ +int bdi_setup_and_register(struct backing_dev_info *bdi, char *name, + unsigned int cap) +{ + char tmp[32]; + int err; + + bdi->name = name; + bdi->capabilities = cap; + err = bdi_init(bdi); + if (err) + return err; + + sprintf(tmp, "%.28s%s", name, "-%d"); + err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq)); + if (err) { + bdi_destroy(bdi); + return err; + } + + return 0; +} +EXPORT_SYMBOL(bdi_setup_and_register); + static wait_queue_head_t congestion_wqh[2] = { __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) -- cgit v1.2.3-70-g09d2 From 5129a469a91a91427334c40e29e64c6d0ab68caf Mon Sep 17 00:00:00 2001 From: Jörn Engel Date: Sun, 25 Apr 2010 08:54:42 +0200 Subject: Catch filesystems lacking s_bdi noop_backing_dev_info is used only as a flag to mark filesystems that don't have any backing store, like tmpfs, procfs, spufs, etc. Signed-off-by: Joern Engel Changed the BUG_ON() to a WARN_ON(). Note that adding dirty inodes to the noop_backing_dev_info is not legal and will not result in them being flushed, but we already catch this condition in __mark_inode_dirty() when checking for a registered bdi. Signed-off-by: Jens Axboe --- fs/super.c | 8 +++++--- fs/sync.c | 3 ++- include/linux/backing-dev.h | 1 + mm/backing-dev.c | 5 +++++ 4 files changed, 13 insertions(+), 4 deletions(-) (limited to 'mm/backing-dev.c') diff --git a/fs/super.c b/fs/super.c index f35ac602210..dc72491a19f 100644 --- a/fs/super.c +++ b/fs/super.c @@ -693,6 +693,7 @@ int set_anon_super(struct super_block *s, void *data) return -EMFILE; } s->s_dev = MKDEV(0, dev & MINORMASK); + s->s_bdi = &noop_backing_dev_info; return 0; } @@ -954,10 +955,11 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void if (error < 0) goto out_free_secdata; BUG_ON(!mnt->mnt_sb); + WARN_ON(!mnt->mnt_sb->s_bdi); - error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); - if (error) - goto out_sb; + error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); + if (error) + goto out_sb; /* * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE diff --git a/fs/sync.c b/fs/sync.c index fc5c3d75cf3..92b228176f7 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "internal.h" #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \ @@ -32,7 +33,7 @@ static int __sync_filesystem(struct super_block *sb, int wait) * This should be safe, as we require bdi backing to actually * write out data in the first place */ - if (!sb->s_bdi) + if (!sb->s_bdi || sb->s_bdi == &noop_backing_dev_info) return 0; if (sb->s_qcop && sb->s_qcop->quota_sync) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index e19c677f219..bd0e3c6f323 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -247,6 +247,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); #endif extern struct backing_dev_info default_backing_dev_info; +extern struct backing_dev_info noop_backing_dev_info; void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page); int writeback_in_progress(struct backing_dev_info *bdi); diff --git a/mm/backing-dev.c b/mm/backing-dev.c index dbda4707f59..707d0dc6da0 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -27,6 +27,11 @@ struct backing_dev_info default_backing_dev_info = { }; EXPORT_SYMBOL_GPL(default_backing_dev_info); +struct backing_dev_info noop_backing_dev_info = { + .name = "noop", +}; +EXPORT_SYMBOL_GPL(noop_backing_dev_info); + static struct class *bdi_class; /* -- cgit v1.2.3-70-g09d2