kernel/linux.git/drivers/md/bitmap.c, branch linux-2.6.16.y

md: avoid possible BUG_ON in md bitmap handling

2007-08-23T00:13:17+00:00

md/bitmap tracks how many active write requests are pending on blocks associated with each bit in the bitmap, so that it knows when it can clear the bit (when count hits zero). The counter has 14 bits of space, so if there are ever more than 16383, we cannot cope. Currently the code just calles BUG_ON as "all" drivers have request queue limits much smaller than this. However is seems that some don't. Apparently some multipath configurations can allow more than 16383 concurrent write requests. So, in this unlikely situation, instead of calling BUG_ON we now wait for the count to drop down a bit. This requires a new wait_queue_head, some waiting code, and a wakeup call. Tested by limiting the counter to 20 instead of 16383 (writes go a lot slower in that case...). Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk

md/bitmap: tidy up i_writecount handling in md/bitmap

2007-08-11T23:09:29+00:00

md/bitmap modifies i_writecount of a bitmap file to make sure that no-one else writes to it. The reverting of the change is sometimes done twice, and there is one error path where it is omitted. This patch tidies that up. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk

md/bitmap: remove dead code from md/bitmap

2007-08-11T23:07:37+00:00

bitmap_active is never called, and the BITMAP_ACTIVE flag is never users or tested, so discard them both. Also remove some out-of-date 'todo' comments. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk

md/bitmap: remove unnecessary page reference manipulations from md/bitmap code

2007-08-11T23:05:36+00:00

md/bitmap gets a collection of pages representing the bitmap when it initialises the bitmap, and puts all the references when discarding the bitmap. It also occasionally takes extra references without any good reason, and sometimes drops them ... though it doesn't always drop them, which can result in a memory leak. This patch removes the unnecessary 'get_page' calls, and the corresponding 'put_page' calls. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk

md/bitmap: use set_bit etc for bitmap page attributes

2007-08-11T23:04:41+00:00

In particular, this means that we use 4 bits per page instead of a whole unsigned long. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk

md/bitmap: cleaner separation of page attribute handlers in md/bitmap

2007-08-11T23:03:48+00:00

md/bitmap has some attributes per-page. Handling of these attributes in largely abstracted in set_page_attr and clear_page_attr. However get_page_attr exposes the format used to store them. So prior to changing that format, introduce test_page_attr instead of get_page_attr, and make appropriate usage changes. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk

[PATCH] Unlinline a bunch of other functions

2006-01-15T02:27:06+00:00

Remove the "inline" keyword from a bunch of big functions in the kernel with the goal of shrinking it by 30kb to 40kb Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar Acked-by: Jeff Garzik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] md: make sure bitmap updates are visible through filesystem

2006-01-06T16:34:08+00:00

When we update a page_cache page in the kernel, we need to flush_dache_page or userspace might not see the change. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] md: define and use safe_put_page for md

2006-01-06T16:34:07+00:00

md sometimes call put_page on NULL pointers (treating it like kfree). This is not safe, so define and use a 'safe_put_page' which checks for NULL. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] md: remove inappropriate limits in md/bitmap configuration.

2006-01-06T16:34:07+00:00

The kernel should not be imposing these policy limits: The time between bitmap updates should certainly be allowed to be more than 15 seconds, and if someone wants a bitmap chunk size in excess of 4MB, the kernel isn't the place to stop them. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds