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authorChristoph Hellwig <hch@lst.de>2023-06-15 09:48:39 +0300
committerSong Liu <song@kernel.org>2023-07-27 10:13:29 +0300
commita34d4ef82c3c4bd8bda817e9fb53ef37c5595ddd (patch)
tree19f0e7a3a90aadd603d603382a0a6fdb8a5cadd7 /drivers/md
parentd7038f951828da19fa9aafddfa087b69032c9687 (diff)
downloadlinux-a34d4ef82c3c4bd8bda817e9fb53ef37c5595ddd.tar.xz
md: make bitmap file support optional
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> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20230615064840.629492-11-hch@lst.de
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/Kconfig10
-rw-r--r--drivers/md/md-bitmap.c15
-rw-r--r--drivers/md/md.c7
3 files changed, 32 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index b0a22e99bade..9712ab9bcba5 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 a280bfd29f65..a58a4c30265e 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 @@ out:
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 320d71537359..f46996a95b0c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7043,6 +7043,13 @@ 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) {