- 28 Jan, 2014 40 commits
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Miao Xie authored
When we ran the 274th case of xfstests with nodatacow mount option, We met the following warning message: WARNING: CPU: 1 PID: 14185 at fs/btrfs/extent-tree.c:3734 btrfs_free_reserved_data_space+0xa6/0xd0 It is caused by the race between the write back and nocow buffered write: Task1 Task2 __btrfs_buffered_write() skip data reservation reserve the metadata space copy the data dirty the pages unlock the pages write back the pages release the data space becasue there is no noreserve flag set the noreserve flag This patch fixes this problem by unlocking the pages after the noreserve flag is set. Reported-by:Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by:
Miao Xie <miaox@cn.fujitsu.com> Signed-off-by:
Josef Bacik <jbacik@fb.com> Signed-off-by:
Chris Mason <clm@fb.com>
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Josef Bacik authored
The backref walking code will search down to the key it is looking for and then proceed to walk _all_ of the extents on the file until it hits the end. This is suboptimal with large files, we only need to look for as many extents as we have references for that inode. I have a testcase that creates a randomly written 4 gig file and before this patch it took 6min 30sec to do the initial send, with this patch it takes 2min 30sec to do the intial send. Thanks, Signed-off-by:
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Josef Bacik authored
Could have sworn I fixed this before but apparently not. This makes us pass btrfs/022 with skinny metadata enabled. Thanks, Signed-off-by:
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Josef Bacik authored
I don't think this is an issue and I've not seen it in practice but extent_from_logical will fail to find a skinny extent because it uses btrfs_previous_item and gives it the normal extent item type. This is just not a place to use btrfs_previous_item since we care about either normal extents or skinny extents, so open code btrfs_previous_item to properly check. This would only affect metadata and the only place this is used for metadata is scrub and I'm pretty sure it's just for printing stuff out, not actually doing any work so hopefully it was never a problem other than a cosmetic one. Thanks, Signed-off-by:
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Josef Bacik authored
On one of our gluster clusters we noticed some pretty big lag spikes. This turned out to be because our transaction commit was taking like 3 minutes to complete. This is because we have like 30 gigs of metadata, so our global reserve would end up being the max which is like 512 mb. So our throttling code would allow a ridiculous amount of delayed refs to build up and then they'd all get run at transaction commit time, and for a cold mounted file system that could take up to 3 minutes to run. So fix the throttling to be based on both the size of the global reserve and how long it takes us to run delayed refs. This patch tracks the time it takes to run delayed refs and then only allows 1 seconds worth of outstanding delayed refs at a time. This way it will auto-tune itself from cold cache up to when everything is in memory and it no longer has to go to disk. This makes our transaction commits take much less time to run. Thanks, Signed-off-by:
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Josef Bacik authored
Currently we have two rb-trees, one for delayed ref heads and one for all of the delayed refs, including the delayed ref heads. When we process the delayed refs we have to hold onto the delayed ref lock for all of the selecting and merging and such, which results in quite a bit of lock contention. This was solved by having a waitqueue and only one flusher at a time, however this hurts if we get a lot of delayed refs queued up. So instead just have an rb tree for the delayed ref heads, and then attach the delayed ref updates to an rb tree that is per delayed ref head. Then we only need to take the delayed ref lock when adding new delayed refs and when selecting a delayed ref head to process, all the rest of the time we deal with a per delayed ref head lock which will be much less contentious. The locking rules for this get a little more complicated since we have to lock up to 3 things to properly process delayed refs, but I will address that problem later. For now this passes all of xfstests and my overnight stress tests. Thanks, Signed-off-by:
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Josef Bacik authored
Looking into some performance related issues with large amounts of metadata revealed that we can have some pretty huge swings in fsync() performance. If we have a lot of delayed refs backed up (as you will tend to do with lots of metadata) fsync() will wander off and try to run some of those delayed refs which can result in reading from disk and such. Since the actual act of fsync() doesn't create any delayed refs there is no need to make it throttle on delayed ref stuff, that will be handled by other people. With this patch we get much smoother fsync performance with large amounts of metadata. Thanks, Signed-off-by:
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Filipe David Borba Manana authored
This change adds infrastructure to allow for generic properties for inodes. Properties are name/value pairs that can be associated with inodes for different purposes. They are stored as xattrs with the prefix "btrfs." Properties can be inherited - this means when a directory inode has inheritable properties set, these are added to new inodes created under that directory. Further, subvolumes can also have properties associated with them, and they can be inherited from their parent subvolume. Naturally, directory properties have priority over subvolume properties (in practice a subvolume property is just a regular property associated with the root inode, objectid 256, of the subvolume's fs tree). This change also adds one specific property implementation, named "compression", whose values can be "lzo" or "zlib" and it's an inheritable property. The corresponding changes to btrfs-progs were also implemented. A patch with xfstests for this feature will follow once there's agreement on this change/feature. Further, the script at the bottom of this commit message was used to do some benchmarks to measure any performance penalties of this feature. Basically the tests correspond to: Test 1 - create a filesystem and mount it with compress-force=lzo, then sequentially create N files of 64Kb each, measure how long it took to create the files, unmount the filesystem, mount the filesystem and perform an 'ls -lha' against the test directory holding the N files, and report the time the command took. Test 2 - create a filesystem and don't use any compression option when mounting it - instead set the compression property of the subvolume's root to 'lzo'. Then create N files of 64Kb, and report the time it took. The unmount the filesystem, mount it again and perform an 'ls -lha' like in the former test. This means every single file ends up with a property (xattr) associated to it. Test 3 - same as test 2, but uses 4 properties - 3 are duplicates of the compression property, have no real effect other than adding more work when inheriting properties and taking more btree leaf space. Test 4 - same as test 3 but with 10 properties per file. Results (in seconds, and averages of 5 runs each), for different N numbers of files follow. * Without properties (test 1) file creation time ls -lha time 10 000 files 3.49 0.76 100 000 files 47.19 8.37 1 000 000 files 518.51 107.06 * With 1 property (compression property set to lzo - test 2) file creation time ls -lha time 10 000 files 3.63 0.93 100 000 files 48.56 9.74 1 000 000 files 537.72 125.11 * With 4 properties (test 3) file creation time ls -lha time 10 000 files 3.94 1.20 100 000 files 52.14 11.48 1 000 000 files 572.70 142.13 * With 10 properties (test 4) file creation time ls -lha time 10 000 files 4.61 1.35 100 000 files 58.86 13.83 1 000 000 files 656.01 177.61 The increased latencies with properties are essencialy because of: *) When creating an inode, we now synchronously write 1 more item (an xattr item) for each property inherited from the parent dir (or subvolume). This could be done in an asynchronous way such as we do for dir intex items (delayed-inode.c), which could help reduce the file creation latency; *) With properties, we now have larger fs trees. For this particular test each xattr item uses 75 bytes of leaf space in the fs tree. This could be less by using a new item for xattr items, instead of the current btrfs_dir_item, since we could cut the 'location' and 'type' fields (saving 18 bytes) and maybe 'transid' too (saving a total of 26 bytes per xattr item) from the btrfs_dir_item type. Also tried batching the xattr insertions (ignoring proper hash collision handling, since it didn't exist) when creating files that inherit properties from their parent inode/subvolume, but the end results were (surprisingly) essentially the same. Test script: $ cat test.pl #!/usr/bin/perl -w use strict; use Time::HiRes qw(time); use constant NUM_FILES => 10_000; use constant FILE_SIZES => (64 * 1024); use constant DEV => '/dev/sdb4'; use constant MNT_POINT => '/home/fdmanana/btrfs-tests/dev'; use constant TEST_DIR => (MNT_POINT . '/testdir'); system("mkfs.btrfs", "-l", "16384", "-f", DEV) == 0 or die "mkfs.btrfs failed!"; # following line for testing without properties #system("mount", "-o", "compress-force=lzo", DEV, MNT_POINT) == 0 or die "mount failed!"; # following 2 lines for testing with properties system("mount", DEV, MNT_POINT) == 0 or die "mount failed!"; system("btrfs", "prop", "set", MNT_POINT, "compression", "lzo") == 0 or die "set prop failed!"; system("mkdir", TEST_DIR) == 0 or die "mkdir failed!"; my ($t1, $t2); $t1 = time(); for (my $i = 1; $i <= NUM_FILES; $i++) { my $p = TEST_DIR . '/file_' . $i; open(my $f, '>', $p) or die "Error opening file!"; $f->autoflush(1); for (my $j = 0; $j < FILE_SIZES; $j += 4096) { print $f ('A' x 4096) or die "Error writing to file!"; } close($f); } $t2 = time(); print "Time to create " . NUM_FILES . ": " . ($t2 - $t1) . " seconds.\n"; system("umount", DEV) == 0 or die "umount failed!"; system("mount", DEV, MNT_POINT) == 0 or die "mount failed!"; $t1 = time(); system("bash -c 'ls -lha " . TEST_DIR . " > /dev/null'") == 0 or die "ls failed!"; $t2 = time(); print "Time to ls -lha all files: " . ($t2 - $t1) . " seconds.\n"; system("umount", DEV) == 0 or die "umount failed!"; Signed-off-by:Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by:
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Filipe David Borba Manana authored
When writing to a file we drop existing file extent items that cover the write range and then add a new file extent item that represents that write range. Before this change we were doing a tree lookup to remove the file extent items, and then after we did another tree lookup to insert the new file extent item. Most of the time all the file extent items we need to drop are located within a single leaf - this is the leaf where our new file extent item ends up at. Therefore, in this common case just combine these 2 operations into a single one. By avoiding the second btree navigation for insertion of the new file extent item, we reduce btree node/leaf lock acquisitions/releases, btree block/leaf COW operations, CPU time on btree node/leaf key binary searches, etc. Besides for file writes, this is an operation that happens for file fsync's as well. However log btrees are much less likely to big as big as regular fs btrees, therefore the impact of this change is smaller. The following benchmark was performed against an SSD drive and a HDD drive, both for random and sequential writes: sysbench --test=fileio --file-num=4096 --file-total-size=8G \ --file-test-mode=[rndwr|seqwr] --num-threads=512 \ --file-block-size=8192 \ --max-requests=1000000 \ --file-fsync-freq=0 --file-io-mode=sync [prepare|run] All results below are averages of 10 runs of the respective test. ** SSD sequential writes Before this change: 225.88 Mb/sec After this change: 277.26 Mb/sec ** SSD random writes Before this change: 49.91 Mb/sec After this change: 56.39 Mb/sec ** HDD sequential writes Before this change: 68.53 Mb/sec After this change: 69.87 Mb/sec ** HDD random writes Before this change: 13.04 Mb/sec After this change: 14.39 Mb/sec Signed-off-by: -
Wang Shilong authored
We may return early in btrfs_drop_snapshot(), we shouldn't call btrfs_std_err() for this case, fix it. Cc: stable@vger.kernel.org Signed-off-by:
Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by:
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Wang Shilong authored
We will finish orphan cleanups during snapshot, so we don't have to commit transaction here. Signed-off-by:
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Wang Shilong authored
We should gurantee that parent and clone roots can not be destroyed during send, for this we have two ideas. 1.by holding @subvol_sem, this might be a nightmare, because it will block all subvolumes deletion for a long time. 2.Miao pointed out we can reuse @send_in_progress, that mean we will skip snapshot deletion if root sending is in progress. Here we adopt the second approach since it won't block other subvolumes deletion for a long time. Besides in btrfs_clean_one_deleted_snapshot(), we only check first root , if this root is involved in send, we return directly rather than continue to check.There are several reasons about it: 1.this case happen seldomly. 2.after sending,cleaner thread can continue to drop that root. 3.make code simple Cc: David Sterba <dsterba@suse.cz> Signed-off-by:
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Wang Shilong authored
Steps to reproduce: # mkfs.btrfs -f /dev/sda8 # mount /dev/sda8 /mnt # btrfs sub snapshot -r /mnt /mnt/snap1 # btrfs sub snapshot -r /mnt /mnt/snap2 # btrfs send /mnt/snap1 -p /mnt/snap2 -f /mnt/1 # dmesg The problem is that we will sort clone roots(include @send_root), it might push @send_root before thus @send_root's @send_in_progress will be decreased twice. Cc: David Sterba <dsterba@suse.cz> Signed-off-by:
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Qu Wenruo authored
Add treelog mount option to enable tree log with remount option. Signed-off-by:
Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by:
David Sterba <dsterba@suse.cz> Signed-off-by:
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Qu Wenruo authored
Add datasum mount option to enable checksum with remount option. Signed-off-by:
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Qu Wenruo authored
Add datacow mount option to enable copy-on-write with remount option. Signed-off-by:
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Qu Wenruo authored
Add acl mount option to enable acl with remount option. Signed-off-by:
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Qu Wenruo authored
Add noflushoncommit mount option to disable flush on commit with remount option. Signed-off-by:
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Qu Wenruo authored
Add noenospc_debug mount option to disable ENOSPC debug with remount option. Signed-off-by:
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Qu Wenruo authored
Add nodiscard mount option to disable discard with remount option. Signed-off-by:
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Qu Wenruo authored
Btrfs has autodefrag mount option but no pairing noautodefrag option, which makes it impossible to disable autodefrag without umount. Signed-off-by:
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Qu Wenruo authored
Btrfs can be remounted without barrier, but there is no "barrier" option so nobody can remount btrfs back with barrier on. Only umount and mount again can re-enable barrier.(Quite awkward) Also the mount options in the document is also changed slightly for the further pairing options changes. Reported-by:
Daniel Blueman <daniel@quora.org> Signed-off-by:
Mike Fleetwood <mike.fleetwood@googlemail.com> Reviewed-by:
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Wang Shilong authored
We only intent to fua the first superblock in every device from comments, fix it. Signed-off-by:
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Liu Bo authored
@full is not protected within global_rsv.lock, so we may think global_rsv is already full but in fact it's not, so we miss the opportunity to return free space to global_rsv directly when we release other block_rsvs. Signed-off-by:
Liu Bo <bo.li.liu@oracle.com> Signed-off-by:
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Wang Shilong authored
During balance test, we hit an oops: [ 2013.841551] kernel BUG at fs/btrfs/relocation.c:1174! The problem is that if we fail to relocate tree blocks, we should update backref cache, otherwise, some pending nodes are not updated while snapshot check @cache->last_trans is within one transaction and won't update it and then oops happen. Signed-off-by:
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Miao Xie authored
The following warning message was outputed when running the 274th case of xfstests with nodatacow option: BUG: Bad page state in process kswapd0 pfn:1c66f page:ffffea0000636848 count:0 mapcount:0 mapping:(null) index:0x78000 page flags: 0x1000000000100a(error|uptodate|private_2) It is because the check of nocow range was wrong, we should compare the start and end position of the extent with the write position to verify if the write position was in the extent, but the current code just used the start postion to do the check, so we got the wrong extent and told the caller that it was a nocow write. And then when we write back the dirty pages, we found we should cow the extent, but at that time, there was no space in the fs, we had to the error flag for the page. When someone reclaimed that page, the above warning outputed. Fix it. Reported-by:
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Wang Shilong authored
Previously, we will free reloc root memory and then force filesystem to be readonly. The problem is that there may be another thread commiting transaction which will try to access freed reloc root during merging reloc roots process. To keep consistency snapshots shared space, we should allow snapshot finished if possible, so here we don't free reloc root memory. signed-off-by:
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Wang Shilong authored
@nr is no longer used, remove it from select_reloc_root() Signed-off-by:
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Filipe David Borba Manana authored
If we do a btree search with the goal of updating an existing item without changing its size (ins_len == 0 and cow == 1), then we never need to hold locks on upper level nodes (even when slot == 0) after we COW their child nodes/leaves, as we won't have node splits or merges in this scenario (that is, no key additions, removals or shifts on any nodes or leaves). Therefore release the locks immediately after COWing the child nodes/leaves while navigating the btree, even if their parent slot is 0, instead of returning a path to the caller with those nodes locked, which would get released only when the caller releases or frees the path (or if it calls btrfs_unlock_up_safe). This is a common scenario, for example when updating inode items in fs trees and block group items in the extent tree. The following benchmarks were performed on a quad core machine with 32Gb of ram, using a leaf/node size of 4Kb (to generate deeper fs trees more quickly). sysbench --test=fileio --file-num=131072 --file-total-size=8G \ --file-test-mode=seqwr --num-threads=512 --file-block-size=8192 \ --max-requests=100000 --file-io-mode=sync [prepare|run] Before this change: 49.85Mb/s (average of 5 runs) After this change: 50.38Mb/s (average of 5 runs) Signed-off-by: -
Wenliang Fan authored
The local variable 'new_size' comes from userspace. If a large number was passed, there would be an integer overflow in the following line: new_size = old_size + new_size; Signed-off-by:
Wenliang Fan <fanwlexca@gmail.com> Signed-off-by:
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Josef Bacik authored
We can starve out the transaction commit with a bunch of caching threads all running at the same time. This is because we will only drop the extent_commit_sem if we need_resched(), which isn't likely to happen since we will be reading a lot from the disk so have already schedule()'ed plenty. Alex observed that he could starve out a transaction commit for up to a minute with 32 caching threads all running at once. This will allow us to drop the extent_commit_sem to allow the transaction commit to swap the commit_root out and then all the cachers will start back up. Here is an explanation provided by Igno So, just to fill in what happens in this loop: mutex_unlock(&caching_ctl->mutex); cond_resched(); goto again; where 'again:' takes caching_ctl->mutex and fs_info->extent_commit_sem again: again: mutex_lock(&caching_ctl->mutex); /* need to make sure the commit_root doesn't disappear */ down_read(&fs_info->extent_commit_sem); So, if I'm reading the code correct, there can be a fair amount of concurrency here: there may be multiple 'caching kthreads' per filesystem active, while there's one fs_info->extent_commit_sem per filesystem AFAICS. So, what happens if there are a lot of CPUs all busy holding the ->extent_commit_sem rwsem read-locked and a writer arrives? They'd all rush to try to release the fs_info->extent_commit_sem, and they'd block in the down_read() because there's a writer waiting. So there's a guarantee of forward progress. This should answer akpm's concern I think. Thanks, Acked-by:Ingo Molnar <mingo@kernel.org> Signed-off-by:
Josef Bacik <jbacik@fusionio.com> Signed-off-by:
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Josef Bacik authored
Btrfs needs a simple way to know if it needs to let go of it's read lock on a rwsem. Introduce rwsem_is_contended to check to see if there are any waiters on this rwsem currently. This is just a hueristic, it is meant to be light and not 100% accurate and called by somebody already holding on to the rwsem in either read or write. Thanks, Signed-off-by:
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Miao Xie authored
The inode reference item is close to inode item, so we insert it simultaneously with the inode item insertion when we create a file/directory.. In fact, we also can handle the inode reference deletion by the same way. So we made this patch to introduce the delayed inode reference deletion for the single link inode(At most case, the file doesn't has hard link, so we don't take the hard link into account). This function is based on the delayed inode mechanism. After applying this patch, we can reduce the time of the file/directory deletion by ~10%. Signed-off-by:
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Miao Xie authored
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Miao Xie authored
Two reasons: - btrfs_end_transaction_dmeta() is the same as btrfs_end_transaction_throttle() so it is unnecessary. - All the delayed items should be dealt in the current transaction, so the workers should not commit the transaction, instead, deal with the delayed items as many as possible. So we can remove btrfs_end_transaction_dmeta() Signed-off-by:
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Miao Xie authored
- move the condition check for wait into a function - use wait_event_interruptible instead of prepare-schedule-finish process Signed-off-by:
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Miao Xie authored
If the number of the delayed items is greater than the upper limit, we will try to flush all the delayed items. After that, it is unnecessary to run them again because they are being dealt with by the wokers or the number of them is less than the lower limit. Signed-off-by:
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Miao Xie authored
Before applying the patch commit de3cb945 title: Btrfs: improve the delayed inode throttling We need requeue the async work after the current work was done, it introduced a deadlock problem. So we wrote the code that this patch removes to avoid the above problem. But after applying the above patch, the deadlock problem didn't exist. So we should remove that fix code. Signed-off-by:
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Frank Holton authored
Convert all applicable cases of printk and pr_* to the btrfs_* macros. Fix all uses of the BTRFS prefix. Signed-off-by:
Frank Holton <fholton@gmail.com> Signed-off-by:
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Filipe David Borba Manana authored
While running the test btrfs/004 from xfstests in a loop, it failed about 1 time out of 20 runs in my desktop. The failure happened in the backref walking part of the test, and the test's error message was like this: btrfs/004 93s ... [failed, exit status 1] - output mismatch (see /home/fdmanana/git/hub/xfstests_2/results//btrfs/004.out.bad) --- tests/btrfs/004.out 2013-11-26 18:25:29.263333714 +0000 +++ /home/fdmanana/git/hub/xfstests_2/results//btrfs/004.out.bad 2013-12-10 15:25:10.327518516 +0000 @@ -1,3 +1,8 @@ QA output created by 004 *** test backref walking -*** done +unexpected output from + /home/fdmanana/git/hub/btrfs-progs/btrfs inspect-internal logical-resolve -P 141512704 /home/fdmanana/btrfs-tests/scratch_1 +expected inum: 405, expected address: 454656, file: /home/fdmanana/btrfs-tests/scratch_1/snap1/p0/d6/d3d/d156/fce, got: + ... (Run 'diff -u tests/btrfs/004.out /home/fdmanana/git/hub/xfstests_2/results//btrfs/004.out.bad' to see the entire diff) Ran: btrfs/004 Failures: btrfs/004 Failed 1 of 1 tests But immediately after the test finished, the btrfs inspect-internal command returned the expected output: $ btrfs inspect-internal logical-resolve -P 141512704 /home/fdmanana/btrfs-tests/scratch_1 inode 405 offset 454656 root 258 inode 405 offset 454656 root 5 It turned out this was because the btrfs_search_old_slot() calls performed during backref walking (backref.c:__resolve_indirect_ref) were not finding anything. The reason for this turned out to be that the tree mod logging code was not logging some node multi-step operations atomically, therefore btrfs_search_old_slot() callers iterated often over an incomplete tree that wasn't fully consistent with any tree state from the past. Besides missing items, this often (but not always) resulted in -EIO errors during old slot searches, reported in dmesg like this: [ 4299.933936] ------------[ cut here ]------------ [ 4299.933949] WARNING: CPU: 0 PID: 23190 at fs/btrfs/ctree.c:1343 btrfs_search_old_slot+0x57b/0xab0 [btrfs]() [ 4299.933950] Modules linked in: btrfs raid6_pq xor pci_stub vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) bnep rfcomm bluetooth parport_pc ppdev binfmt_misc joydev snd_hda_codec_h [ 4299.933977] CPU: 0 PID: 23190 Comm: btrfs Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [ 4299.933978] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./Z77 Pro4, BIOS P1.50 09/04/2012 [ 4299.933979] 000000000000053f ffff8806f3fd98f8 ffffffff8176d284 0000000000000007 [ 4299.933982] 0000000000000000 ffff8806f3fd9938 ffffffff8104a81c ffff880659c64b70 [ 4299.933984] ffff880659c643d0 ffff8806599233d8 ffff880701e2e938 0000160000000000 [ 4299.933987] Call Trace: [ 4299.933991] [<ffffffff8176d284>] dump_stack+0x55/0x76 [ 4299.933994] [<ffffffff8104a81c>] warn_slowpath_common+0x8c/0xc0 [ 4299.933997] [<ffffffff8104a86a>] warn_slowpath_null+0x1a/0x20 [ 4299.934003] [<ffffffffa065d3bb>] btrfs_search_old_slot+0x57b/0xab0 [btrfs] [ 4299.934005] [<ffffffff81775f3b>] ? _raw_read_unlock+0x2b/0x50 [ 4299.934010] [<ffffffffa0655001>] ? __tree_mod_log_search+0x81/0xc0 [btrfs] [ 4299.934019] [<ffffffffa06dd9b0>] __resolve_indirect_refs+0x130/0x5f0 [btrfs] [ 4299.934027] [<ffffffffa06a21f1>] ? free_extent_buffer+0x61/0xc0 [btrfs] [ 4299.934034] [<ffffffffa06de39c>] find_parent_nodes+0x1fc/0xe40 [btrfs] [ 4299.934042] [<ffffffffa06b13e0>] ? defrag_lookup_extent+0xe0/0xe0 [btrfs] [ 4299.934048] [<ffffffffa06b13e0>] ? defrag_lookup_extent+0xe0/0xe0 [btrfs] [ 4299.934056] [<ffffffffa06df980>] iterate_extent_inodes+0xe0/0x250 [btrfs] [ 4299.934058] [<ffffffff817762db>] ? _raw_spin_unlock+0x2b/0x50 [ 4299.934065] [<ffffffffa06dfb82>] iterate_inodes_from_logical+0x92/0xb0 [btrfs] [ 4299.934071] [<ffffffffa06b13e0>] ? defrag_lookup_extent+0xe0/0xe0 [btrfs] [ 4299.934078] [<ffffffffa06b7015>] btrfs_ioctl+0xf65/0x1f60 [btrfs] [ 4299.934080] [<ffffffff811658b8>] ? handle_mm_fault+0x278/0xb00 [ 4299.934083] [<ffffffff81075563>] ? up_read+0x23/0x40 [ 4299.934085] [<ffffffff8177a41c>] ? __do_page_fault+0x20c/0x5a0 [ 4299.934088] [<ffffffff811b2946>] do_vfs_ioctl+0x96/0x570 [ 4299.934090] [<ffffffff81776e23>] ? error_sti+0x5/0x6 [ 4299.934093] [<ffffffff810b71e8>] ? trace_hardirqs_off_caller+0x28/0xd0 [ 4299.934096] [<ffffffff81776a09>] ? retint_swapgs+0xe/0x13 [ 4299.934098] [<ffffffff811b2eb1>] SyS_ioctl+0x91/0xb0 [ 4299.934100] [<ffffffff813eecde>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 4299.934102] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b [ 4299.934102] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b [ 4299.934104] ---[ end trace 48f0cfc902491414 ]--- [ 4299.934378] btrfs bad fsid on block 0 These tree mod log operations that must be performed atomically, tree_mod_log_free_eb, tree_mod_log_eb_copy, tree_mod_log_insert_root and tree_mod_log_insert_move, used to be performed atomically before the following commit: c8cc6341 (Btrfs: stop using GFP_ATOMIC for the tree mod log allocations) That change removed the atomicity of such operations. This patch restores the atomicity while still not doing the GFP_ATOMIC allocations of tree_mod_elem structures, so it has to do the allocations using GFP_NOFS before acquiring the mod log lock. This issue has been experienced by several users recently, such as for example: http://www.spinics.net/lists/linux-btrfs/msg28574.html After running the btrfs/004 test for 679 consecutive iterations with this patch applied, I didn't ran into the issue anymore. Cc: stable@vger.kernel.org Signed-off-by:
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