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* btrfs: force chunk allocation if our global rsv is larger than metadataJosef Bacik2020-05-251-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nikolay noticed a bunch of test failures with my global rsv steal patches. At first he thought they were introduced by them, but they've been failing for a while with 64k nodes. The problem is with 64k nodes we have a global reserve that calculates out to 13MiB on a freshly made file system, which only has 8MiB of metadata space. Because of changes I previously made we no longer account for the global reserve in the overcommit logic, which means we correctly allow overcommit to happen even though we are already overcommitted. However in some corner cases, for example btrfs/170, we will allocate the entire file system up with data chunks before we have enough space pressure to allocate a metadata chunk. Then once the fs is full we ENOSPC out because we cannot overcommit and the global reserve is taking up all of the available space. The most ideal way to deal with this is to change our space reservation stuff to take into account the height of the tree's that we're modifying, so that our global reserve calculation does not end up so obscenely large. However that is a huge undertaking. Instead fix this by forcing a chunk allocation if the global reserve is larger than the total metadata space. This gives us essentially the same behavior that happened before, we get a chunk allocated and these tests can pass. This is meant to be a stop-gap measure until we can tackle the "tree height only" project. Fixes: 0096420adb03 ("btrfs: do not account global reserve in can_overcommit") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: Remove __ prefix from btrfs_block_rsv_releaseNikolay Borisov2020-03-231-5/+6
| | | | | | | | | | | | | Currently the non-prefixed version is a simple wrapper used to hide the 4th argument of the prefixed version. This doesn't bring much value in practice and only makes the code harder to follow by adding another level of indirection. Rectify this by removing the __ prefix and have only one public function to release bytes from a block reservation. No semantic changes. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: slightly simplify global block reserve calculationsAnand Jain2020-03-231-1/+1
| | | | | | | | | | | | | | | | | | In btrfs_update_global_block_rsv the lines: num_bytes = block_rsv->size - block_rsv->reserved; block_rsv->reserved += num_bytes; imply: block_rsv->reserved = block_rsv->size; Assign block_rsv->size to block_rsv->reserved directly and reorder lines so they match the other branch. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: add a comment describing block reservesJosef Bacik2020-03-231-0/+92
| | | | | | | | | | This is a giant comment at the top of block-rsv.c describing generally how block reserves work. It is purely about the block reserves themselves, and nothing to do with how the actual reservation system works. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: use btrfs_try_granting_tickets in update_global_rsvJosef Bacik2019-09-091-0/+1
| | | | | | | | | | | | | | | | We have some annoying xfstests tests that will create a very small fs, fill it up, delete it, and repeat to make sure everything works right. This trips btrfs up sometimes because we may commit a transaction to free space, but most of the free metadata space was being reserved by the global reserve. So we commit and update the global reserve, but the space is simply added to bytes_may_use directly, instead of trying to add it to existing tickets. This results in ENOSPC when we really did have space. Fix this by calling btrfs_try_granting_tickets once we add back our excess space to wake any pending tickets. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: always reserve our entire size for the global reserveJosef Bacik2019-09-091-9/+4
| | | | | | | | | | | | | | | | While messing with the overcommit logic I noticed that sometimes we'd ENOSPC out when really we should have run out of space much earlier. It turns out it's because we'll only reserve up to the free amount left in the space info for the global reserve, but that doesn't make sense with overcommit because we could be well above our actual size. This results in the global reserve not carving out it's entire reservation, and thus not putting enough pressure on the rest of the infrastructure to do the right thing and ENOSPC out at a convenient time. Fix this by always taking our full reservation amount for the global reserve. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: change the minimum global reserve sizeJosef Bacik2019-09-091-1/+21
| | | | | | | | | | | | | | | It made sense to have the global reserve set at 16M in the past, but since it is used less nowadays set the minimum size to the number of items we'll need to update the main trees we update during a transaction commit, plus some slop area so we can do unlinks if we need to. In practice this doesn't affect normal file systems, but for xfstests where we do things like fill up a fs and then rm * it can fall over in weird ways. This enables us for more sane behavior at extremely small file system sizes. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: rename btrfs_space_info_add_old_bytesJosef Bacik2019-09-091-2/+3
| | | | | | | | | | | This name doesn't really fit with how the space reservation stuff works now, rename it to btrfs_space_info_free_bytes_may_use so it's clear what the function is doing. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: roll tracepoint into btrfs_space_info_update helperJosef Bacik2019-09-091-5/+0
| | | | | | | | | We duplicate this tracepoint everywhere we call these helpers, so update the helper to have the tracepoint as well. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: move math functions to misc.hDavid Sterba2019-09-091-1/+1
| | | | | Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: migrate the global_block_rsv helpers to block-rsv.cJosef Bacik2019-07-021-0/+172
| | | | | | | These helpers belong in block-rsv.c Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: migrate the block-rsv code to block-rsv.cJosef Bacik2019-07-021-0/+253
This moves everything out of extent-tree.c to block-rsv.c. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>