| Message ID | 20230615064840.629492-11-hch@lst.de (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [01/11] md-bitmap: set BITMAP_WRITE_ERROR in write_sb_page | expand |
On 6/15/23 08:48, Christoph Hellwig wrote: > The support for write intent bitmaps in files on an external files in md > is a hot mess that abuses ->bmap to map file offsets into physical device > objects, and also abuses buffer_heads in a creative way. > > Make this code optional so that MD can be built into future kernels > without buffer_head support, and so that we can eventually deprecate it. > > Note this does not affect the internal bitmap support, which has none of > the problems. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/md/Kconfig | 10 ++++++++++ > drivers/md/md-bitmap.c | 15 +++++++++++++++ > drivers/md/md.c | 7 +++++++ > 3 files changed, 32 insertions(+) > Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
> On Jun 14, 2023, at 11:48 PM, Christoph Hellwig <hch@lst.de> wrote: > > The support for write intent bitmaps in files on an external files in md > is a hot mess that abuses ->bmap to map file offsets into physical device > objects, and also abuses buffer_heads in a creative way. > > Make this code optional so that MD can be built into future kernels > without buffer_head support, and so that we can eventually deprecate it. > > Note this does not affect the internal bitmap support, which has none of > the problems. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/md/Kconfig | 10 ++++++++++ > drivers/md/md-bitmap.c | 15 +++++++++++++++ > drivers/md/md.c | 7 +++++++ > 3 files changed, 32 insertions(+) > > diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig > index b0a22e99bade37..9712ab9bcba52e 100644 > --- a/drivers/md/Kconfig > +++ b/drivers/md/Kconfig > @@ -50,6 +50,16 @@ config MD_AUTODETECT > > If unsure, say Y. > > +config MD_BITMAP_FILE > + bool "MD bitmap file support" > + default y > + help > + If you say Y here, support for write intent bitmaps in files on an > + external file system is enabled. This is an alternative to the internal > + bitmaps near the MD superblock, and very problematic code that abuses > + various kernel APIs and can only work with files on a file system not > + actually sitting on the MD device. > + > config MD_LINEAR > tristate "Linear (append) mode (deprecated)" > depends on BLK_DEV_MD > diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c > index ed402f4dad182d..1e29088b1f081a 100644 > --- a/drivers/md/md-bitmap.c > +++ b/drivers/md/md-bitmap.c > @@ -295,6 +295,7 @@ static void write_sb_page(struct bitmap *bitmap, unsigned long pg_index, > > static void md_bitmap_file_kick(struct bitmap *bitmap); > > +#ifdef CONFIG_MD_BITMAP_FILE > static void write_file_page(struct bitmap *bitmap, struct page *page, int wait) > { > struct buffer_head *bh = page_buffers(page); > @@ -408,6 +409,20 @@ static int read_file_page(struct file *file, unsigned long index, > ret); > return ret; > } > +#else /* CONFIG_MD_BITMAP_FILE */ > +static void write_file_page(struct bitmap *bitmap, struct page *page, int wait) > +{ > +} > +static int read_file_page(struct file *file, unsigned long index, > + struct bitmap *bitmap, unsigned long count, struct page *page) > +{ > + return -EIO; > +} > +static void free_buffers(struct page *page) > +{ > + put_page(page); > +} > +#endif /* CONFIG_MD_BITMAP_FILE */ > > /* > * bitmap file superblock operations > diff --git a/drivers/md/md.c b/drivers/md/md.c > index cf3733c90c47ed..c9fcefaf9c073b 100644 > --- a/drivers/md/md.c > +++ b/drivers/md/md.c > @@ -7020,6 +7020,13 @@ static int set_bitmap_file(struct mddev *mddev, int fd) > > if (mddev->bitmap || mddev->bitmap_info.file) > return -EEXIST; /* cannot add when bitmap is present */ > + > + if (!IS_ENABLED(CONFIG_MD_BITMAP_FILE)) { > + pr_warn("%s: bitmap files not supported by this kernel\n", > + mdname(mddev)); > + return -EINVAL; > + } > + > f = fget(fd); > > if (f == NULL) { > -- > 2.39.2 > Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index b0a22e99bade37..9712ab9bcba52e 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -50,6 +50,16 @@ config MD_AUTODETECT If unsure, say Y. +config MD_BITMAP_FILE + bool "MD bitmap file support" + default y + help + If you say Y here, support for write intent bitmaps in files on an + external file system is enabled. This is an alternative to the internal + bitmaps near the MD superblock, and very problematic code that abuses + various kernel APIs and can only work with files on a file system not + actually sitting on the MD device. + config MD_LINEAR tristate "Linear (append) mode (deprecated)" depends on BLK_DEV_MD diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index ed402f4dad182d..1e29088b1f081a 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -295,6 +295,7 @@ static void write_sb_page(struct bitmap *bitmap, unsigned long pg_index, static void md_bitmap_file_kick(struct bitmap *bitmap); +#ifdef CONFIG_MD_BITMAP_FILE static void write_file_page(struct bitmap *bitmap, struct page *page, int wait) { struct buffer_head *bh = page_buffers(page); @@ -408,6 +409,20 @@ static int read_file_page(struct file *file, unsigned long index, ret); return ret; } +#else /* CONFIG_MD_BITMAP_FILE */ +static void write_file_page(struct bitmap *bitmap, struct page *page, int wait) +{ +} +static int read_file_page(struct file *file, unsigned long index, + struct bitmap *bitmap, unsigned long count, struct page *page) +{ + return -EIO; +} +static void free_buffers(struct page *page) +{ + put_page(page); +} +#endif /* CONFIG_MD_BITMAP_FILE */ /* * bitmap file superblock operations diff --git a/drivers/md/md.c b/drivers/md/md.c index cf3733c90c47ed..c9fcefaf9c073b 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -7020,6 +7020,13 @@ static int set_bitmap_file(struct mddev *mddev, int fd) if (mddev->bitmap || mddev->bitmap_info.file) return -EEXIST; /* cannot add when bitmap is present */ + + if (!IS_ENABLED(CONFIG_MD_BITMAP_FILE)) { + pr_warn("%s: bitmap files not supported by this kernel\n", + mdname(mddev)); + return -EINVAL; + } + f = fget(fd); if (f == NULL) {
The support for write intent bitmaps in files on an external files in md is a hot mess that abuses ->bmap to map file offsets into physical device objects, and also abuses buffer_heads in a creative way. Make this code optional so that MD can be built into future kernels without buffer_head support, and so that we can eventually deprecate it. Note this does not affect the internal bitmap support, which has none of the problems. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/md/Kconfig | 10 ++++++++++ drivers/md/md-bitmap.c | 15 +++++++++++++++ drivers/md/md.c | 7 +++++++ 3 files changed, 32 insertions(+)