kernel.git/fs/ocfs2/localalloc.c, branch linux-2.6.37.y

ocfs2: Limit default local alloc size within bitmap range.

2010-06-15T23:50:43Z

In commit 6b82021b9e91cd689fdffadbcdb9a42597bbe764, we increase our local alloc size and calculate how much megabytes we can get according to group size and volume size. But we also need to check the maximum bits a local alloc block bitmap can have. With a bs=512, cs=32K, local volume with 160G, it calculate 96MB while the maximum local alloc size is only 76M. So the bitmap will overflow and corrupt the system truncate log file. See bug http://oss.oracle.com/bugzilla/show_bug.cgi?id=1262 Signed-off-by: Tao Ma Acked-by: Mark Fasheh Signed-off-by: Joel Becker

ocfs2: ocfs2_group_bitmap_size has to handle old volume.

2010-04-13T06:38:06Z

ocfs2_group_bitmap_size has to handle the case when the volume don't have discontiguous block group support. So pass the feature_incompat in and check it. Signed-off-by: Tao Ma

ocfs2: ocfs2_claim_*() don't need an ocfs2_super argument.

2010-05-06T05:59:06Z

They all take an ocfs2_alloc_context, which has the allocation inode. Signed-off-by: Joel Becker Signed-off-by: Tao Ma

ocfs2: Define data structures for discontiguous block groups.

2010-04-13T06:26:12Z

Defines the OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG feature bit and modifies struct ocfs2_group_desc for the feature. Signed-off-by: Joel Becker Signed-off-by: Tao Ma

ocfs2/trivial: Code cleanup for allocation reservation.

2010-05-06T01:18:09Z

Two tiny cleanup for allocation reservation. 1. Remove some extra codes in ocfs2_local_alloc_find_clear_bits. 2. Remove an unuseful variables in ocfs2_find_resv_lhs. Signed-off-by: Tao Ma Acked-by: Mark Fasheh Signed-off-by: Joel Becker

ocfs2: increase the default size of local alloc windows

2010-05-06T01:18:07Z

I have observed that the current size of 8M gives us pretty poor fragmentation on multi-threaded workloads which do lots of writes. Generally, I can increase the size of local alloc windows and observe a marked decrease in fragmentation, even up and beyond window sizes of 512 megabytes. This makes sense for a couple reasons - larger local alloc means more room for reservation windows. On multi-node workloads the larger local alloc helps as well because we don't have to do window slides as often. Also, I removed the OCFS2_DEFAULT_LOCAL_ALLOC_SIZE constant as it is no longer used and the comment above it was out of date. To test fragmentation, I used a workload which launched 4 threads that did 4k writes into a series of about 140 alternating files. With resv_level=2, and a 4k/4k file system I observed the following average fragmentation for various localalloc= parameters: localalloc= avg. fragmentation 8 48 32 16 64 10 120 7 On larger cluster sizes, the difference is more dramatic. The new default size top out at 256M, which we'll only get for cluster sizes of 32K and above. Signed-off-by: Mark Fasheh Signed-off-by: Joel Becker

ocfs2: clean up localalloc mount option size parsing

2010-05-06T01:18:06Z

This patch pulls the local alloc sizing code into localalloc.c and provides a callout to it from ocfs2_fill_super(). Behavior is essentially unchanged except that I correctly calculate the maximum local alloc size. The old code in ocfs2_parse_options() calculated the max size as: ocfs2_local_alloc_size(sb) * 8 which is correct, in bits. Unfortunately though the option passed in is in megabytes. Ultimately, this bug made no real difference - the shrink code would catch a too-large size and bring it down to something reasonable. Still, it's less than efficient as-is. Signed-off-by: Mark Fasheh Signed-off-by: Joel Becker

ocfs2: remove ocfs2_local_alloc_in_range()

2010-05-06T01:17:31Z

Inodes are always allocated from the global bitmap now so we don't need this any more. Also, the existing implementation bounces reservations around needlessly. Signed-off-by: Mark Fasheh

ocfs2: allocation reservations

2010-05-06T01:17:30Z

This patch improves Ocfs2 allocation policy by allowing an inode to reserve a portion of the local alloc bitmap for itself. The reserved portion (allocation window) is advisory in that other allocation windows might steal it if the local alloc bitmap becomes full. Otherwise, the reservations are honored and guaranteed to be free. When the local alloc window is moved to a different portion of the bitmap, existing reservations are discarded. Reservation windows are represented internally by a red-black tree. Within that tree, each node represents the reservation window of one inode. An LRU of active reservations is also maintained. When new data is written, we allocate it from the inodes window. When all bits in a window are exhausted, we allocate a new one as close to the previous one as possible. Should we not find free space, an existing reservation is pulled off the LRU and cannibalized. Signed-off-by: Mark Fasheh

ocfs2: Make ocfs2_journal_dirty() void.

2010-05-06T01:17:29Z

jbd[2]_journal_dirty_metadata() only returns 0. It's been returning 0 since before the kernel moved to git. There is no point in checking this error. ocfs2_journal_dirty() has been faithfully returning the status since the beginning. All over ocfs2, we have blocks of code checking this can't fail status. In the past few years, we've tried to avoid adding these checks, because they are pointless. But anyone who looks at our code assumes they are needed. Finally, ocfs2_journal_dirty() is made a void function. All error checking is removed from other files. We'll BUG_ON() the status of jbd2_journal_dirty_metadata() just in case they change it someday. They won't. Signed-off-by: Joel Becker