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2017-08-18btrfs: use appropriate define for the fsidAnand Jain4-13/+13
Though BTRFS_FSID_SIZE and BTRFS_UUID_SIZE are of the same size, we should use the matching constant for the fsid buffer. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-18btrfs: increase ctx->pos for delayed dir indexJosef Bacik1-0/+1
Our dir_context->pos is supposed to hold the next position we're supposed to look. If we successfully insert a delayed dir index we could end up with a duplicate entry because we don't increase ctx->pos after doing the dir_emit. Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: fix readdir deadlock with pagefaultJosef Bacik4-34/+110
Readdir does dir_emit while under the btree lock. dir_emit can trigger the page fault which means we can deadlock. Fix this by allocating a buffer on opening a directory and copying the readdir into this buffer and doing dir_emit from outside of the tree lock. Thread A readdir <holding tree lock> dir_emit <page fault> down_read(mmap_sem) Thread B mmap write down_write(mmap_sem) page_mkwrite wait_ordered_extents Process C finish_ordered_extent insert_reserved_file_extent try to lock leaf <hang> Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> [ copy the deadlock scenario to changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Simplify math in should_alloc chunkNikolay Borisov1-5/+4
Currently should_alloc_chunk uses ->total_bytes - ->bytes_readonly to signify the total amount of bytes in this space info. However, given Jeff's patch which adds bytes_pinned and bytes_may_use to the calculation of num_allocated it becomes a lot more clear to just eliminate num_bytes altogether and add the bytes_readonly to the amount of used space. That way we don't change the results of the following statements. In the process also start using btrfs_space_info_used. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: account for pinned bytes in should_alloc_chunkJeff Mahoney1-1/+1
In a heavy write scenario, we can end up with a large number of pinned bytes. This can translate into (very) premature ENOSPC because pinned bytes must be accounted for when allowing a reservation but aren't accounted for when deciding whether to create a new chunk. This patch adds the accounting to should_alloc_chunk so that we can create the chunk. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: prepare for extensions in compression optionsDavid Sterba2-4/+4
This is a minimal patch intended to be backported to older kernels. We're going to extend the string specifying the compression method and this would fail on kernels before that change (the string is compared exactly). Relax the string matching only to the prefix, ie. ignoring anything that goes after "zlib" or "lzo", regardless of th format extension we decide to use. This applies to the mount options and properties. That way, patched old kernels could be booted on systems already utilizing the new compression spec. Applicable since commit 63541927c8d11, v3.14. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: allow defrag compress to override NOCOMPRESS attributeDavid Sterba1-3/+3
Currently, the BTRFS_INODE_NOCOMPRESS will prevent any compression on a given file, except when the mount is force-compress. As users have reported on IRC, this will also prevent compression when requested by defrag (btrfs fi defrag -c file). The nocompress flag is set automatically by filesystem when the ratios are bad and the user would have to manually drop the bit in order to make defrag -c work. This is not good from the usability perspective. This patch will raise priority for the defrag -c over nocompress, ie. any file with NOCOMPRESS bit set will get defragmented. The bit will remain untouched. Alternate option was to also drop the nocompress bit and keep the decision logic as is, but I think this is not the right solution. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: defrag: cleanup checking for compression statusDavid Sterba1-6/+6
Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: separate defrag and property compressionDavid Sterba3-3/+14
Add new value for compression to distinguish between defrag and property. Previously, a single variable was used and this caused clashes when the per-file 'compression' was set and a defrag -c was called. The property-compression is loaded when the file is open, defrag will overwrite the same variable and reset to 0 (ie. NONE) at when the file defragmentaion is finished. That's considered a usability bug. Now we won't touch the property value, use the defrag-compression. The precedence of defrag is higher than for property (and whole-filesystem). Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: rename variable holding per-inode compression typeDavid Sterba4-12/+12
This is preparatory for separating inode compression requested by defrag and set via properties. This will fix a usability bug when defrag will reset compression type to NONE. If the file has compression set via property, it will not apply anymore (until next mount or reset through command line). We're going to fix that by adding another variable just for the defrag call and won't touch the property. The defrag will have higher priority when deciding whether to compress the data. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16Btrfs: add skeleton code for compression heuristicTimofey Titovets3-4/+39
Add skeleton code for compresison heuristics. Now it iterates over all the pages, but in the end always says "yes, compress please", ie it does not change the current behaviour. In the future we're going to add various heuristics to analyze the data. This patch can be used as a baseline for measuring if the effectivness and performance. Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> [ enhanced changelog, modified comments ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: account that we're waiting for IO in scrub_submit_raid56_bio_waitDavid Sterba1-1/+1
Correctly account for IO when waiting for a submitted bio in scrub. This only for the accounting purposes and should not change other behaviour. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: account that we're waiting for DIO readDavid Sterba1-2/+2
Correctly account for IO when waiting for a submitted DIO read, the case when we're retrying. This only for the accounting purposes and should not change other behaviour. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: drop chunk locks at the end of close_ctreeDavid Sterba1-2/+0
The pinned chunks might be left over so we clean them but at this point of close_ctree, there's noone to race with, the locking can be removed. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: remove trivial wrapper btrfs_force_raDavid Sterba3-11/+3
It's a simple call page_cache_sync_readahead, same arguments in the same order. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: drop ancient page flag mappingsDavid Sterba1-7/+0
There's no PageFsMisc. Added by patch 4881ee5a2e995 in 2008, the flag is not present in current kernels. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: fix spelling of snapshottingDavid Sterba6-36/+36
Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Make flush_space return voidNikolay Borisov1-8/+8
The return value of flush_space was used to have significance in the early days when the code was first introduced and before the ticketed enospc rework. Since the latter got introduced the return value lost any significance whatsoever to its callers. So let's remove it. While at it also remove the unused ticket variable in btrfs_async_reclaim_metadata_space. It was used in the initial version of the ticketed ENOSPC work, however Wang Xiaoguang detected a problem with this and fixed it in ce129655c9d9 ("btrfs: introduce tickets_id to determine whether asynchronous metadata reclaim work makes progress"). Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comment ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Deprecate userspace transaction ioctlsNikolay Borisov1-0/+11
Userspace transactions were introduced in commit 6bf13c0cc833 ("Btrfs: transaction ioctls") to provide semantics that Ceph's object store required. However, things have changed significantly since then, to the point where btrfs is no longer suitable as a backend for ceph and in fact it's actively advised against such usages. Considering this, there doesn't seem to be a widespread, legit use case of userspace transaction. They also clutter the file->private pointer. So to end the agony let's nuke the userspace transaction ioctls. As a first step let's give time for people to voice their objection by just WARN()ining when the userspace transaction is used. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ move the warning past perm checks, keep the has-been-printed state; we're ok with just one warning over all filesystems ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: use named constant for bdev blocksizeDavid Sterba4-11/+20
Superblock is read and written using buffer heads, we need to set the bdev blocksize. The magic constant has been hardcoded in several places, so replace it with a named constant. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: split write_dev_supers to two functionsDavid Sterba1-56/+73
There are two independent parts, one that writes the superblocks and another that waits for completion. No functional changes, but cleanups, reformatting and comment updates. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: refactor find_device helperDavid Sterba1-6/+13
Polish the helper: * drop underscores, no special meaning here * pass fs_devices, as this is what the API implements * drop noinline, no apparent reason for such simple helper * constify uuid * add comment Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: merge alloc_device helpersDavid Sterba1-25/+11
There are two helpers called in chain from one location, we can merge the functionaliy. Originally, alloc_fs_devices could fill the device uuid randomly if we we didn't give the uuid buffer. This happens for seed devices but the fsid is generated in btrfs_prepare_sprout, so we can remove it. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: merge REQ_OP and REQ_ flags to one parameter in submit_extent_pageDavid Sterba1-6/+8
The function submit_extent_page has 15(!) parameters right now, op and op_flags are effectively one value stored to bio::bi_opf, no need to pass them separately. So it's 14 parameters now. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: cleanup types storing REQ_*David Sterba2-7/+9
Unify types of local variables and parameters that store various REQ_* values to unsigned int. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: get fs_info from eb in btrfs_print_tree, remove argumentDavid Sterba2-3/+5
Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: get fs_info from eb in btrfs_print_leaf, remove argumentDavid Sterba6-15/+17
Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: simplify btrfs_dev_replace_kthreadDavid Sterba1-17/+11
This function prints an informative message and then continues dev-replace. The message contains a progress percentage which is read from the status. The status is allocated dynamically, about 2600 bytes, just to read the single value. That's an overkill. We'll use the new helper and drop the allocation. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: factor reading progress out of btrfs_dev_replace_statusDavid Sterba1-16/+30
We'll want to read the percentage value from dev_replace elsewhere, move the logic to a separate helper. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: defrag: make readahead state allocation failure non-fatalDavid Sterba1-7/+8
All sorts of readahead errors are not considered fatal. We can continue defragmentation without it, with some potential slow down, which will last only for the current inode. Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: use GFP_KERNEL in btrfs_defrag_fileDavid Sterba1-3/+2
We can safely use GFP_KERNEL, the function is called from two contexts: - ioctl handler, called directly, no locks taken - cleaner thread, running all queued defrag work, outside of any locks Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: use GFP_KERNEL in mount and remountDavid Sterba1-7/+8
We don't need to restrict the allocation flags in btrfs_mount or _remount. No big filesystem locks are held (possibly s_umount but that does no count here). Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Remove never reached error handling code in __add_reloc_rootNikolay Borisov1-2/+0
One of the error handling paths in __add_reloc_root contains btrfs_panic() followed by some other code. As the name implies what it does is print some error message and call BUG, naturally what follow afterwards is not invoked. So remove this extra code. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Remove unused parameters from volume.c functionsNikolay Borisov4-11/+5
This also adjusts the respective callers in other files. Those were found with -Wunused-parameter. btrfs_full_stripe_len's mapping_tree - introduced by 53b381b3abeb ("Btrfs: RAID5 and RAID6") but it was never really used even in that commit btrfs_is_parity_mirror's mirror_num - same as above chunk_drange_filter's chunk_offset - introduced by 94e60d5a5c4b ("Btrfs: devid subset filter") and never used. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Remove unused variablesNikolay Borisov1-9/+0
clear_super - usage was removed in commit cea67ab92d3d ("btrfs: clean the old superblocks before freeing the device") but that change forgot to remove the actual variable. max_key - commit 6174d3cb43aa ("Btrfs: remove unused max_key arg from btrfs_search_forward") removed the max_key parameter but it forgot to remove references from callers. stripe_len - this one was added by e06cd3dd7cea ("Btrfs: add validadtion checks for chunk loading") but even then it wasn't used. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Remove find_raid56_stripe_lenNikolay Borisov1-20/+7
find_raid56_stripe_len statically returns SZ_64K which equals BTRFS_STRIPE_LEN. It's sole caller is __btrfs_alloc_chunk and it assigns the return value to ai variable which is already set to BTRFS_STRIPE_LEN. So remove the function invocation altogether and remove the function itself. Also remove the variable since it's only aliasing BTRFS_STRIPE_LEN and use the define directly. Use the occassion to simplify the rounding down of stripe_size now that the value we want it to align is a power of 2. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Use explicit round_down macro in btrfs resize ioctl handlerNikolay Borisov1-2/+1
No functional changes, just make the code more self-explanatory. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: btrfs_inherit_iflags() can be staticAnand Jain3-32/+31
btrfs_new_inode() is the only consumer move it to inode.c, from ioctl.c. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Keep one more workspace aroundNick Terrell1-1/+1
find_workspace() allocates up to num_online_cpus() + 1 workspaces. free_workspace() will only keep num_online_cpus() workspaces. When (de)compressing we will allocate num_online_cpus() + 1 workspaces, then free one, and repeat. Instead, we can just keep num_online_cpus() + 1 workspaces around, and never have to allocate/free another workspace in the common case. I tested on a Ubuntu 14.04 VM with 2 cores and 4 GiB of RAM. I mounted a BtrFS partition with -o compress-force={lzo,zlib,zstd} and logged whenever a workspace was allocated of freed. Then I copied vmlinux (527 MB) to the partition. Before the patch, during the copy it would allocate and free 5-6 workspaces. After, it only allocated the initial 3. This held true for lzo, zlib, and zstd. The time it took to execute cp vmlinux /mnt/btrfs && sync dropped from 1.70s to 1.44s with lzo compression, and from 2.04s to 1.80s for zstd compression. Signed-off-by: Nick Terrell <terrelln@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: drop newlines from strings when using btrfs_* helpersDavid Sterba5-6/+5
The helpers append "\n" so we can keep the actual strings shorter. The extra newline will print an empty line. Some messages have been slightly modified to be more consistent with the rest (lowercase first letter). Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: qgroups: Fix BUG_ON condition in tree level checkNikolay Borisov1-1/+1
The current code was erroneously checking for root_level > BTRFS_MAX_LEVEL. If we had a root_level of 8 then the check won't trigger and we could potentially hit a buffer overflow. The correct check should be root_level >= BTRFS_MAX_LEVEL . Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <quwenruo.btrfs@gmx.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Enhance message when a device is missing during mountQu Wenruo2-7/+19
For a missing device, btrfs will just refuse to mount with almost meaningless kernel message like: BTRFS info (device vdb6): disk space caching is enabled BTRFS info (device vdb6): has skinny extents BTRFS error (device vdb6): failed to read the system array: -5 BTRFS error (device vdb6): open_ctree failed This patch will print a new message about the missing device: BTRFS info (device vdb6): disk space caching is enabled BTRFS info (device vdb6): has skinny extents BTRFS warning (device vdb6): devid 2 uuid 80470722-cad2-4b90-b7c3-fee294552f1b is missing BTRFS error (device vdb6): failed to read the system array: -5 BTRFS error (device vdb6): open_ctree failed Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Cleanup num_tolerated_disk_barrier_failuresQu Wenruo4-75/+0
As we use per-chunk degradable check, the global num_tolerated_disk_barrier_failures is of no use. We can now remove it. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Allow barrier_all_devices to do chunk level device checkQu Wenruo1-13/+3
The last user of num_tolerated_disk_barrier_failures is barrier_all_devices(). But it can be easily changed to the new per-chunk degradable check framework. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Do chunk level check for degraded remountQu Wenruo1-2/+1
Just the same for mount time check, use btrfs_check_rw_degradable() to check if we are OK to be remounted rw. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Do chunk level check for degraded rw mountQu Wenruo1-8/+3
Now use the btrfs_check_rw_degradable() to check if we can mount in the degraded mode. With this patch, we can mount in the following case: # mkfs.btrfs -f -m raid1 -d single /dev/sdb /dev/sdc # wipefs -a /dev/sdc # mount /dev/sdb /mnt/btrfs -o degraded As the single data chunk is only on sdb, so it's OK to mount as degraded, as missing one device is OK for RAID1. But still fail in the following case as expected: # mkfs.btrfs -f -m raid1 -d single /dev/sdb /dev/sdc # wipefs -a /dev/sdb # mount /dev/sdc /mnt/btrfs -o degraded As the data chunk is only in sdb, so it's not OK to mount it as degraded. Reported-by: Zhao Lei <zhaolei@cn.fujitsu.com> Reported-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Introduce a function to check if all chunks a OK for degraded rw mountQu Wenruo2-0/+60
Introduce a new function, btrfs_check_rw_degradable(), to check if all chunks in btrfs is OK for degraded rw mount. It provides the new basis for accurate btrfs mount/remount and even runtime degraded mount check other than old one-size-fit-all method. Btrfs currently uses num_tolerated_disk_barrier_failures to do global check for tolerated missing device. Although the one-size-fit-all solution is quite safe, it's too strict if data and metadata has different duplication level. For example, if one use Single data and RAID1 metadata for 2 disks, it means any missing device will make the fs unable to be degraded mounted. But in fact, some times all single chunks may be in the existing device and in that case, we should allow it to be rw degraded mounted. Such case can be easily reproduced using the following script: # mkfs.btrfs -f -m raid1 -d sing /dev/sdb /dev/sdc # wipefs -f /dev/sdc # mount /dev/sdb -o degraded,rw If using btrfs-debug-tree to check /dev/sdb, one should find that the data chunk is only in sdb, so in fact it should allow degraded mount. This patchset will introduce a new per-chunk degradable check for btrfs, allow above case to succeed, and it's quite small anyway. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> [ copied text from cover letter with more details about the problem being solved ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16Btrfs: report errors when checksum is not foundLiu Bo1-2/+0
When btrfs fails the checksum check, it'll fill the whole page with "1". However, if %csum_expected is 0 (which means there is no checksum), then for some unknown reason, we just pretend that the read is correct, so userspace would be confused about the dilemma that read is successful but getting a page with all content being "1". This can happen due to a bug in btrfs-convert. This fixes it by always returning errors if checksum doesn't match. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Prevent possible ERR_PTR() dereferenceNikolay Borisov1-10/+12
In btrfs_full_stripe_len/btrfs_is_parity_mirror we have similar code which gets the chunk map for a particular range via get_chunk_map. However, get_chunk_map can return an ERR_PTR value and while the 2 callers do catch this with a WARN_ON they then proceed to indiscriminately dereference the extent map. This of course leads to a crash. Fix the offenders by making the dereference conditional on IS_ERR. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: Remove redundant checks from btrfs_alloc_data_chunk_ondemandNikolay Borisov1-9/+2
Many commits ago the data space_info in alloc_data_chunk_ondemand used to be acquired from the inode. At that point commit 33b4d47f5e24 ("Btrfs: deal with NULL space info") got introduced to deal with spurios cases where the space info could be null, following a rebalance. Nowadays, however, the space info is referenced directly from the btrfs_fs_info struct which is initialised at filesystem mount time. This makes the null checks redundant, so remove them. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>