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| author | Jörn Engel <joern@logfs.org> | 2010-04-25 08:54:42 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2010-04-25 08:54:42 +0200 |
| commit | 5129a469a91a91427334c40e29e64c6d0ab68caf (patch) | |
| tree | 141a17cbea94c7c9c038187cc7081e1c688eac55 | |
| parent | 7e2455c1a123ceadbb35150a610d61e8443fd340 (diff) | |
| download | lwn-5129a469a91a91427334c40e29e64c6d0ab68caf.tar.gz lwn-5129a469a91a91427334c40e29e64c6d0ab68caf.zip | |
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 <joern@logfs.org>
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 <jens.axboe@oracle.com>
| -rw-r--r-- | fs/super.c | 8 | ||||
| -rw-r--r-- | fs/sync.c | 3 | ||||
| -rw-r--r-- | include/linux/backing-dev.h | 1 | ||||
| -rw-r--r-- | mm/backing-dev.c | 5 |
4 files changed, 13 insertions, 4 deletions
diff --git a/fs/super.c b/fs/super.c index f35ac6022109..dc72491a19f9 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 fc5c3d75cf3c..92b228176f7c 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -14,6 +14,7 @@ #include <linux/pagemap.h> #include <linux/quotaops.h> #include <linux/buffer_head.h> +#include <linux/backing-dev.h> #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 e19c677f219c..bd0e3c6f323f 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 dbda4707f593..707d0dc6da0f 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; /* |