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2021-02-08btrfs: fix parameter description of btrfs_add_extent_mappingNikolay Borisov
This fixes the following compiler warnings: fs/btrfs/extent_map.c:601: warning: Function parameter or member 'fs_info' not described in 'btrfs_add_extent_mapping' fs/btrfs/extent_map.c:601: warning: Function parameter or member 'em_tree' not described in 'btrfs_add_extent_mapping' fs/btrfs/extent_map.c:601: warning: Function parameter or member 'em_in' not described in 'btrfs_add_extent_mapping' fs/btrfs/extent_map.c:601: warning: Function parameter or member 'start' not described in 'btrfs_add_extent_mapping' fs/btrfs/extent_map.c:601: warning: Function parameter or member 'len' not described in 'btrfs_add_extent_mapping' Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08btrfs: document modified parameter of add_extent_mappingNikolay Borisov
Fixes fs/btrfs/extent_map.c:399: warning: Function parameter or member 'modified' not described in 'add_extent_mapping' Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12Btrfs: fix race between using extent maps and merging themFilipe Manana
We have a few cases where we allow an extent map that is in an extent map tree to be merged with other extents in the tree. Such cases include the unpinning of an extent after the respective ordered extent completed or after logging an extent during a fast fsync. This can lead to subtle and dangerous problems because when doing the merge some other task might be using the same extent map and as consequence see an inconsistent state of the extent map - for example sees the new length but has seen the old start offset. With luck this triggers a BUG_ON(), and not some silent bug, such as the following one in __do_readpage(): $ cat -n fs/btrfs/extent_io.c 3061 static int __do_readpage(struct extent_io_tree *tree, 3062 struct page *page, (...) 3127 em = __get_extent_map(inode, page, pg_offset, cur, 3128 end - cur + 1, get_extent, em_cached); 3129 if (IS_ERR_OR_NULL(em)) { 3130 SetPageError(page); 3131 unlock_extent(tree, cur, end); 3132 break; 3133 } 3134 extent_offset = cur - em->start; 3135 BUG_ON(extent_map_end(em) <= cur); (...) Consider the following example scenario, where we end up hitting the BUG_ON() in __do_readpage(). We have an inode with a size of 8KiB and 2 extent maps: extent A: file offset 0, length 4KiB, disk_bytenr = X, persisted on disk by a previous transaction extent B: file offset 4KiB, length 4KiB, disk_bytenr = X + 4KiB, not yet persisted but writeback started for it already. The extent map is pinned since there's writeback and an ordered extent in progress, so it can not be merged with extent map A yet The following sequence of steps leads to the BUG_ON(): 1) The ordered extent for extent B completes, the respective page gets its writeback bit cleared and the extent map is unpinned, at that point it is not yet merged with extent map A because it's in the list of modified extents; 2) Due to memory pressure, or some other reason, the MM subsystem releases the page corresponding to extent B - btrfs_releasepage() is called and returns 1, meaning the page can be released as it's not dirty, not under writeback anymore and the extent range is not locked in the inode's iotree. However the extent map is not released, either because we are not in a context that allows memory allocations to block or because the inode's size is smaller than 16MiB - in this case our inode has a size of 8KiB; 3) Task B needs to read extent B and ends up __do_readpage() through the btrfs_readpage() callback. At __do_readpage() it gets a reference to extent map B; 4) Task A, doing a fast fsync, calls clear_em_loggin() against extent map B while holding the write lock on the inode's extent map tree - this results in try_merge_map() being called and since it's possible to merge extent map B with extent map A now (the extent map B was removed from the list of modified extents), the merging begins - it sets extent map B's start offset to 0 (was 4KiB), but before it increments the map's length to 8KiB (4kb + 4KiB), task A is at: BUG_ON(extent_map_end(em) <= cur); The call to extent_map_end() sees the extent map has a start of 0 and a length still at 4KiB, so it returns 4KiB and 'cur' is 4KiB, so the BUG_ON() is triggered. So it's dangerous to modify an extent map that is in the tree, because some other task might have got a reference to it before and still using it, and needs to see a consistent map while using it. Generally this is very rare since most paths that lookup and use extent maps also have the file range locked in the inode's iotree. The fsync path is pretty much the only exception where we don't do it to avoid serialization with concurrent reads. Fix this by not allowing an extent map do be merged if if it's being used by tasks other then the one attempting to merge the extent map (when the reference count of the extent map is greater than 2). Reported-by: ryusuke1925 <st13s20@gm.ibaraki-ct.ac.jp> Reported-by: Koki Mitani <koki.mitani.xg@hco.ntt.co.jp> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206211 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: remove extent_map::bdevDavid Sterba
We can now remove the bdev from extent_map. Previous patches made sure that bio_set_dev is correctly in all places and that we don't need to grab it from latest_bdev or pass it around inside the extent map. Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: assert extent_map bdevs and lookup_map and splitDavid Sterba
This is a preparatory patch for removing extent_map::bdev. There's some history behind the code so this is only precaution to catch if things break before the actual removal happens. Logically, comparing a raw low-level block device (bdev) does not make sense for extent maps (high-level objects). This had no effect in practice but was quite confusing in the code. The lookup_map is set iff EXTENT_FLAG_FS_MAPPING is set. The two pointers were stored in the same bytes and used potentially in two meanings. Now they're split, so the asserts are in place to check that the condition will not change. The lookup map pointer misused bdev, this has been changed in commit 95617d69326c ("btrfs: cleanup, stop casting for extent_map->lookup everywhere") to the explicit type. But the semantics hasn't changed and bdev was not actually used to decide if maps are mergeable. Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09btrfs: assert extent map tree lock in add_extent_mappingDavid Sterba
As add_extent_mapping is called from several functions, let's add the lock annotation. The tree is going to be modified so it must be the exclusive lock. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29btrfs: Optimize unallocated chunks discardNikolay Borisov
Currently unallocated chunks are always trimmed. For example 2 consecutive trims on large storage would trim freespace twice irrespective of whether the space was actually allocated or not between those trims. Optimise this behavior by exploiting the newly introduced alloc_state tree of btrfs_device. A new CHUNK_TRIMMED bit is used to mark those unallocated chunks which have been trimmed and have not been allocated afterwards. On chunk allocation the respective underlying devices' physical space will have its CHUNK_TRIMMED flag cleared. This avoids submitting discards for space which hasn't been changed since the last time discard was issued. This applies to the single mount period of the filesystem as the information is not stored permanently. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29btrfs: replace pending/pinned chunks lists with io treeJeff Mahoney
The pending chunks list contains chunks that are allocated in the current transaction but haven't been created yet. The pinned chunks list contains chunks that are being released in the current transaction. Both describe chunks that are not reflected on disk as in use but are unavailable just the same. The pending chunks list is anchored by the transaction handle, which means that we need to hold a reference to a transaction when working with the list. The way we use them is by iterating over both lists to perform comparisons on the stripes they describe for each device. This is backwards and requires that we keep a transaction handle open while we're trimming. This patchset adds an extent_io_tree to btrfs_device that maintains the allocation state of the device. Extents are set dirty when chunks are first allocated -- when the extent maps are added to the mapping tree. They're cleared when last removed -- when the extent maps are removed from the mapping tree. This matches the lifespan of the pending and pinned chunks list and allows us to do trims on unallocated space safely without pinning the transaction for what may be a lengthy operation. We can also use this io tree to mark which chunks have already been trimmed so we don't repeat the operation. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-25btrfs: Remove impossible condition from mergable_mapsNikolay Borisov
We can never have extents marked as EXTENT_MAP_DELALLOC since this value is only ever used by btrfs_get_extent_fiemap. In this case the extent map is created by btrfs_get_extent_fiemap and is never really published, this flag is used to return the corresponding userspace one. Considering this, it's pointless having a check for EXTENT_MAP_DELALLOC in mergable_maps. Just remove it. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-12-17btrfs: Fix typos in comments and stringsAndrea Gelmini
The typos accumulate over time so once in a while time they get fixed in a large patch. Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15Btrfs: extent_map: use rb_first_cachedLiu Bo
rb_first_cached() trades an extra pointer "leftmost" for doing the same job as rb_first() but in O(1). As evict_inode_truncate_pages() removes all extent mapping by always looking for the first rb entry, it's helpful to use rb_first_cached instead. For more details about the optimization see patch "Btrfs: delayed-refs: use rb_first_cached for href_root". Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-10-15btrfs: change remove_extent_mapping to return voidzhong jiang
remove_extent_mapping uses the variable "ret" for return value, but it is not modified after initialzation. Further, I find that any of the callers do not handle the return value and the callees are only simple functions so the return values does not need to be passed. Signed-off-by: zhong jiang <zhongjiang@huawei.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28btrfs: use fs_info for btrfs_handle_em_exist tracepointDavid Sterba
We really want to know to which filesystem the extent map events belong, but as it cannot be reached from the extent_map pointers, we need to pass it down the callchain. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-04-12btrfs: replace GPL boilerplate by SPDX -- sourcesDavid Sterba
Remove GPL boilerplate text (long, short, one-line) and keep the rest, ie. personal, company or original source copyright statements. Add the SPDX header. Signed-off-by: David Sterba <dsterba@suse.com>
2018-03-26btrfs: add more __cold annotationsDavid Sterba
The __cold functions are placed to a special section, as they're expected to be called rarely. This could help i-cache prefetches or help compiler to decide which branches are more/less likely to be taken without any other annotations needed. Though we can't add more __exit annotations, it's still possible to add __cold (that's also added with __exit). That way the following function categories are tagged: - printf wrappers, error messages - exit helpers Signed-off-by: David Sterba <dsterba@suse.com>
2018-03-26Btrfs: add tracepoint for em's EEXIST caseLiu Bo
This is adding a tracepoint 'btrfs_handle_em_exist' to help debug the subtle bugs around merge_extent_mapping. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-03-26btrfs: remove unused hardirq.hYang Shi
Preempt counter APIs have been split out, currently, hardirq.h just includes irq_enter/exit APIs which are not used by btrfs at all. So, remove the unused hardirq.h. Signed-off-by: Yang Shi <yang.s@alibaba-inc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-22Btrfs: noinline merge_extent_mappingLiu Bo
In order to debug subtle bugs around merge_extent_mapping(), perf probe can be used to check the arguments, but sometimes merge_extent_mapping() got inlined by compiler and couldn't be probed. This is adding noinline attribute to merge_extent_mapping(). Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-22Btrfs: add WARN_ONCE to detect unexpected error from merge_extent_mappingLiu Bo
This is a subtle case, so in order to understand the problem, it'd be good to know the content of existing and em when any error occurs. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-01-22Btrfs: move extent map specific code to extent_map.cLiu Bo
These helpers are extent map specific, move them to extent_map.c. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18btrfs: convert extent_map.refs from atomic_t to refcount_tElena Reshetova
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-26btrfs: Fix slab accounting flagsNikolay Borisov
BTRFS is using a variety of slab caches to satisfy internal needs. Those slab caches are always allocated with the SLAB_RECLAIM_ACCOUNT, meaning allocations from the caches are going to be accounted as SReclaimable. At the same time btrfs is not registering any shrinkers whatsoever, thus preventing memory from the slabs to be shrunk. This means those caches are not in fact reclaimable. To fix this remove the SLAB_RECLAIM_ACCOUNT on all caches apart from the inode cache, since this one is being freed by the generic VFS super_block shrinker. Also set the transaction related caches as SLAB_TEMPORARY, to better document the lifetime of the objects (it just translates to SLAB_RECLAIM_ACCOUNT). Signed-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-05-25btrfs: fix string and comment grammatical issues and typosNicholas D Steeves
Signed-off-by: Nicholas D Steeves <nsteeves@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-03-14btrfs: Fix misspellings in comments.Adam Buchbinder
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-03-11btrfs: move btrfs_compression_type to compression.hAnand Jain
So that its better organized. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-18btrfs: drop null testing before destroy functionsKinglong Mee
Cleanup. kmem_cache_destroy has support NULL argument checking, so drop the double null testing before calling it. Signed-off-by: Kinglong Mee <kinglongmee@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-15btrfs: cleanup, stop casting for extent_map->lookup everywhereJeff Mahoney
Overloading extent_map->bdev to struct map_lookup * might have started out as a means to an end, but it's a pattern that's used all over the place now. Let's get rid of the casting and just add a union instead. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2014-11-21Btrfs: do not move em to modified list when unpinningJosef Bacik
We use the modified list to keep track of which extents have been modified so we know which ones are candidates for logging at fsync() time. Newly modified extents are added to the list at modification time, around the same time the ordered extent is created. We do this so that we don't have to wait for ordered extents to complete before we know what we need to log. The problem is when something like this happens log extent 0-4k on inode 1 copy csum for 0-4k from ordered extent into log sync log commit transaction log some other extent on inode 1 ordered extent for 0-4k completes and adds itself onto modified list again log changed extents see ordered extent for 0-4k has already been logged at this point we assume the csum has been copied sync log crash On replay we will see the extent 0-4k in the log, drop the original 0-4k extent which is the same one that we are replaying which also drops the csum, and then we won't find the csum in the log for that bytenr. This of course causes us to have errors about not having csums for certain ranges of our inode. So remove the modified list manipulation in unpin_extent_cache, any modified extents should have been added well before now, and we don't want them re-logged. This fixes my test that I could reliably reproduce this problem with. Thanks, cc: stable@vger.kernel.org Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-06-19Btrfs: fix NULL pointer crash when running balance and scrub concurrentlyWang Shilong
While running balance, scrub, fsstress concurrently we hit the following kernel crash: [56561.448845] BTRFS info (device sde): relocating block group 11005853696 flags 132 [56561.524077] BUG: unable to handle kernel NULL pointer dereference at 0000000000000078 [56561.524237] IP: [<ffffffffa038956d>] scrub_chunk.isra.12+0xdd/0x130 [btrfs] [56561.524297] PGD 9be28067 PUD 7f3dd067 PMD 0 [56561.524325] Oops: 0000 [#1] SMP [....] [56561.527237] Call Trace: [56561.527309] [<ffffffffa038980e>] scrub_enumerate_chunks+0x24e/0x490 [btrfs] [56561.527392] [<ffffffff810abe00>] ? abort_exclusive_wait+0x50/0xb0 [56561.527476] [<ffffffffa038add4>] btrfs_scrub_dev+0x1a4/0x530 [btrfs] [56561.527561] [<ffffffffa0368107>] btrfs_ioctl+0x13f7/0x2a90 [btrfs] [56561.527639] [<ffffffff811c82f0>] do_vfs_ioctl+0x2e0/0x4c0 [56561.527712] [<ffffffff8109c384>] ? vtime_account_user+0x54/0x60 [56561.527788] [<ffffffff810f768c>] ? __audit_syscall_entry+0x9c/0xf0 [56561.527870] [<ffffffff811c8551>] SyS_ioctl+0x81/0xa0 [56561.527941] [<ffffffff815707f7>] tracesys+0xdd/0xe2 [...] [56561.528304] RIP [<ffffffffa038956d>] scrub_chunk.isra.12+0xdd/0x130 [btrfs] [56561.528395] RSP <ffff88004c0f5be8> [56561.528454] CR2: 0000000000000078 This is because in btrfs_relocate_chunk(), we will free @bdev directly while scrub may still hold extent mapping, and may access freed memory. Fix this problem by wrapping freeing @bdev work into free_extent_map() which is based on reference count. Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-03-10Btrfs: more efficient btrfs_drop_extent_cacheFilipe Manana
While droping extent map structures from the extent cache that cover our target range, we would remove each extent map structure from the red black tree and then add either 1 or 2 new extent map structures if the former extent map covered sections outside our target range. This change simply attempts to replace the existing extent map structure with a new one that covers the subsection we're not interested in, instead of doing a red black remove operation followed by an insertion operation. The number of elements in an inode's extent map tree can get very high for large files under random writes. For example, while running the following test: sysbench --test=fileio --file-num=1 --file-total-size=10G \ --file-test-mode=rndrw --num-threads=32 --file-block-size=32768 \ --max-requests=500000 --file-rw-ratio=2 [prepare|run] I captured the following histogram capturing the number of extent_map items in the red black tree while that test was running: Count: 122462 Range: 1.000 - 172231.000; Mean: 96415.831; Median: 101855.000; Stddev: 49700.981 Percentiles: 90th: 160120.000; 95th: 166335.000; 99th: 171070.000 1.000 - 5.231: 452 | 5.231 - 187.392: 87 | 187.392 - 585.911: 206 | 585.911 - 1827.438: 623 | 1827.438 - 5695.245: 1962 # 5695.245 - 17744.861: 6204 #### 17744.861 - 55283.764: 21115 ############ 55283.764 - 172231.000: 91813 ##################################################### Benchmark: sysbench --test=fileio --file-num=1 --file-total-size=10G --file-test-mode=rndwr \ --num-threads=64 --file-block-size=32768 --max-requests=0 --max-time=60 \ --file-io-mode=sync --file-fsync-freq=0 [prepare|run] Before this change: 122.1Mb/sec After this change: 125.07Mb/sec (averages of 5 test runs) Test machine: quad core intel i5-3570K, 32Gb of ram, SSD Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com>
2014-03-10Btrfs: remove unneeded field / smaller extent_map structureFilipe Manana
We don't need to have an unsigned int field in the extent_map struct to tell us whether the extent map is in the inode's extent_map tree or not. We can use the rb_node struct field and the RB_CLEAR_NODE and RB_EMPTY_NODE macros to achieve the same task. This reduces sizeof(struct extent_map) from 152 bytes to 144 bytes (on a 64 bits system). Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fb.com>
2014-01-28Btrfs: fix extent_map block_len after mergingFilipe David Borba Manana
When merging an extent_map with its right neighbor, increment its block_len with the neighbor's block_len. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-28Btrfs: faster and more efficient extent map insertionFilipe David Borba Manana
Before this change, adding an extent map to the extent map tree of an inode required 2 tree nevigations: 1) doing a tree navigation to search for an existing extent map starting at the same offset or an extent map that overlaps the extent map we want to insert; 2) Another tree navigation to add the extent map to the tree (if the former tree search didn't found anything). This change just merges these 2 steps into a single one. While running first few btrfs xfstests I had noticed these trees easily had a few hundred elements, and then with the following sysbench test it reached over 1100 elements very often. Test: sysbench --test=fileio --file-num=32 --file-total-size=10G \ --file-test-mode=seqwr --num-threads=512 --file-block-size=8192 \ --max-requests=1000000 --file-io-mode=sync [prepare|run] (fs created with mkfs.btrfs -l 4096 -f /dev/sdb3 before each sysbench prepare phase) Before this patch: run 1 - 41.894Mb/sec run 2 - 40.527Mb/sec run 3 - 40.922Mb/sec run 4 - 49.433Mb/sec run 5 - 40.959Mb/sec average - 42.75Mb/sec After this patch: run 1 - 48.036Mb/sec run 2 - 50.21Mb/sec run 3 - 50.929Mb/sec run 4 - 46.881Mb/sec run 5 - 53.192Mb/sec average - 49.85Mb/sec Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-05-06btrfs: make static code static & remove dead codeEric Sandeen
Big patch, but all it does is add statics to functions which are in fact static, then remove the associated dead-code fallout. removed functions: btrfs_iref_to_path() __btrfs_lookup_delayed_deletion_item() __btrfs_search_delayed_insertion_item() __btrfs_search_delayed_deletion_item() find_eb_for_page() btrfs_find_block_group() range_straddles_pages() extent_range_uptodate() btrfs_file_extent_length() btrfs_scrub_cancel_devid() btrfs_start_transaction_lflush() btrfs_print_tree() is left because it is used for debugging. btrfs_start_transaction_lflush() and btrfs_reada_detach() are left for symmetry. ulist.c functions are left, another patch will take care of those. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-06Btrfs: fix bad extent loggingJosef Bacik
A user sent me a btrfs-image of a file system that was panicing on mount during the log recovery. I had originally thought these problems were from a bug in the free space cache code, but that was just a symptom of the problem. The problem is if your application does something like this [prealloc][prealloc][prealloc] the internal extent maps will merge those all together into one extent map, even though on disk they are 3 separate extents. So if you go to write into one of these ranges the extent map will be right since we use the physical extent when doing the write, but when we log the extents they will use the wrong sizes for the remainder prealloc space. If this doesn't happen to trip up the free space cache (which it won't in a lot of cases) then you will get bogus entries in your extent tree which will screw stuff up later. The data and such will still work, but everything else is broken. This patch fixes this by not allowing extents that are on the modified list to be merged. This has the side effect that we are no longer adding everything to the modified list all the time, which means we now have to call btrfs_drop_extents every time we log an extent into the tree. So this allows me to drop all this speciality code I was using to get around calling btrfs_drop_extents. With this patch the testcase I've created no longer creates a bogus file system after replaying the log. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-03-01btrfs: fixup/remove module.h usage as requiredPaul Gortmaker
We want to avoid module.h where posible, since it in turn includes nearly all of header space. This means removing it where it is not required, and using export.h where we are only exporting symbols via EXPORT_SYMBOL and friends. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-02-08Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull btrfs fixes from Chris Mason: "We've got corner cases for updating i_size that ceph was hitting, error handling for quotas when we run out of space, a very subtle snapshot deletion race, a crash while removing devices, and one deadlock between subvolume creation and the sb_internal code (thanks lockdep)." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: move d_instantiate outside the transaction during mksubvol Btrfs: fix EDQUOT handling in btrfs_delalloc_reserve_metadata Btrfs: fix possible stale data exposure Btrfs: fix missing i_size update Btrfs: fix race between snapshot deletion and getting inode Btrfs: fix missing release of the space/qgroup reservation in start_transaction() Btrfs: fix wrong sync_writers decrement in btrfs_file_aio_write() Btrfs: do not merge logged extents if we've removed them from the tree btrfs: don't try to notify udev about missing devices
2013-02-05Btrfs: do not merge logged extents if we've removed them from the treeJosef Bacik
You can run into this problem where if somebody is fsyncing and writing out the existing extents you will have removed the extent map from the em tree, but it's still valid for the current fsync so we go ahead and write it. The problem is we unconditionally try to merge it back into the em tree, but if we've removed it from the em tree that will cause use after free problems. Fix this to only merge if we are still a part of the tree. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-01-25Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull btrfs fixes from Chris Mason: "It turns out that we had two crc bugs when running fsx-linux in a loop. Many thanks to Josef, Miao Xie, and Dave Sterba for nailing it all down. Miao also has a new OOM fix in this v2 pull as well. Ilya fixed a regression Liu Bo found in the balance ioctls for pausing and resuming a running balance across drives. Josef's orphan truncate patch fixes an obscure corruption we'd see during xfstests. Arne's patches address problems with subvolume quotas. If the user destroys quota groups incorrectly the FS will refuse to mount. The rest are smaller fixes and plugs for memory leaks." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (30 commits) Btrfs: fix repeated delalloc work allocation Btrfs: fix wrong max device number for single profile Btrfs: fix missed transaction->aborted check Btrfs: Add ACCESS_ONCE() to transaction->abort accesses Btrfs: put csums on the right ordered extent Btrfs: use right range to find checksum for compressed extents Btrfs: fix panic when recovering tree log Btrfs: do not allow logged extents to be merged or removed Btrfs: fix a regression in balance usage filter Btrfs: prevent qgroup destroy when there are still relations Btrfs: ignore orphan qgroup relations Btrfs: reorder locks and sanity checks in btrfs_ioctl_defrag Btrfs: fix unlock order in btrfs_ioctl_rm_dev Btrfs: fix unlock order in btrfs_ioctl_resize Btrfs: fix "mutually exclusive op is running" error code Btrfs: bring back balance pause/resume logic btrfs: update timestamps on truncate() btrfs: fix btrfs_cont_expand() freeing IS_ERR em Btrfs: fix a bug when llseek for delalloc bytes behind prealloc extents Btrfs: fix off-by-one in lseek ...
2013-01-24Btrfs: do not allow logged extents to be merged or removedJosef Bacik
We drop the extent map tree lock while we're logging extents, so somebody could come in and merge another extent into this one and screw up our logging, or they could even remove us from the list which would keep us from logging the extent or freeing our ref on it, so we need to make sure to not clear LOGGING until after the extent is logged, and then we can merge it to adjacent extents. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-12-18Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull btrfs update from Chris Mason: "A big set of fixes and features. In terms of line count, most of the code comes from Stefan, who added the ability to replace a single drive in place. This is different from how btrfs normally replaces drives, and is much much much faster. Josef is plowing through our synchronous write performance. This pull request does not include the DIO_OWN_WAITING patch that was discussed on the list, but it has a number of other improvements to cut down our latencies and CPU time during fsync/O_DIRECT writes. Miao Xie has a big series of fixes and is spreading out ordered operations over more CPUs. This improves performance and reduces contention. I've put in fixes for error handling around hash collisions. These are going back to individual stable kernels as I test against them. Otherwise we have a lot of fixes and cleanups, thanks everyone! raid5/6 is being rebased against the device replacement code. I'll have it posted this Friday along with a nice series of benchmarks." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (115 commits) Btrfs: fix a bug of per-file nocow Btrfs: fix hash overflow handling Btrfs: don't take inode delalloc mutex if we're a free space inode Btrfs: fix autodefrag and umount lockup Btrfs: fix permissions of empty files not affected by umask Btrfs: put raid properties into global table Btrfs: fix BUG() in scrub when first superblock reading gives EIO Btrfs: do not call file_update_time in aio_write Btrfs: only unlock and relock if we have to Btrfs: use tokens where we can in the tree log Btrfs: optimize leaf_space_used Btrfs: don't memset new tokens Btrfs: only clear dirty on the buffer if it is marked as dirty Btrfs: move checks in set_page_dirty under DEBUG Btrfs: log changed inodes based on the extent map tree Btrfs: add path->really_keep_locks Btrfs: do not mark ems as prealloc if we are writing to them Btrfs: keep track of the extents original block length Btrfs: inline csums if we're fsyncing Btrfs: don't bother copying if we're only logging the inode ...
2012-12-16Btrfs: log changed inodes based on the extent map treeJosef Bacik
We don't really need to copy extents from the source tree since we have all of the information already available to us in the extent_map tree. So instead just write the extents straight to the log tree and don't bother to copy the extent items from the source tree. Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-16Btrfs: do not mark ems as prealloc if we are writing to themJosef Bacik
We are going to use EM's to log extents in the future, so we need to not mark them as prealloc if they aren't actually prealloc extents. Instead mark them with FILLING so we know to ammend mod_start/mod_len and that way we don't confuse the extent logging code. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-10-30btrfs: unpin_extent_cache: fix the typo and unnecessary arguementsLiu Bo
- unpint->unpin - prealloc is no more used Signed-off-by: Liu Bo <liub.liubo@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-10-04Btrfs: do not hold the write_lock on the extent tree while loggingJosef Bacik
Dave Sterba pointed out a sleeping while atomic bug while doing fsync. This is because I'm an idiot and didn't realize that rwlock's were spin locks, so we've been holding this thing while doing allocations and such which is not good. This patch fixes this by dropping the write lock before we do anything heavy and re-acquire it when it is done. We also need to take a ref on the em's in case their corresponding pages are evicted and mark them as being logged so that releasepage does not remove them and doesn't remove them from our local list. Thanks, Reported-by: Dave Sterba <dave@jikos.cz> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-10-01btrfs: polish names of kmem cachesDavid Sterba
Usecase: watch 'grep btrfs < /proc/slabinfo' easy to watch all caches in one go. Signed-off-by: David Sterba <dsterba@suse.cz>
2012-10-01Btrfs: improve fsync by filtering extents that we wantLiu Bo
This is based on Josef's "Btrfs: turbo charge fsync". The above Josef's patch performs very good in random sync write test, because we won't have too much extents to merge. However, it does not performs good on the test: dd if=/dev/zero of=foobar bs=4k count=12500 oflag=sync The reason is when we do sequencial sync write, we need to merge the current extent just with the previous one, so that we can get accumulated extents to log: A(4k) --> AA(8k) --> AAA(12k) --> AAAA(16k) ... So we'll have to flush more and more checksum into log tree, which is the bottleneck according to my tests. But we can avoid this by telling fsync the real extents that are needed to be logged. With this, I did the above dd sync write test (size=50m), w/o (orig) w/ (josef's) w/ (this) SATA 104KB/s 109KB/s 121KB/s ramdisk 1.5MB/s 1.5MB/s 10.7MB/s (613%) Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
2012-10-01Btrfs: turbo charge fsyncJosef Bacik
At least for the vm workload. Currently on fsync we will 1) Truncate all items in the log tree for the given inode if they exist and 2) Copy all items for a given inode into the log The problem with this is that for things like VMs you can have lots of extents from the fragmented writing behavior, and worst yet you may have only modified a few extents, not the entire thing. This patch fixes this problem by tracking which transid modified our extent, and then when we do the tree logging we find all of the extents we've modified in our current transaction, sort them and commit them. We also only truncate up to the xattrs of the inode and copy that stuff in normally, and then just drop any extents in the range we have that exist in the log already. Here are some numbers of a 50 meg fio job that does random writes and fsync()s after every write Original Patched SATA drive 82KB/s 140KB/s Fusion drive 431KB/s 2532KB/s So around 2-6 times faster depending on your hardware. There are a few corner cases, for example if you truncate at all we have to do it the old way since there is no way to be sure what is in the log is ok. This probably could be done smarter, but if you write-fsync-truncate-write-fsync you deserve what you get. All this work is in RAM of course so if your inode gets evicted from cache and you read it in and fsync it we'll do it the slow way if we are still in the same transaction that we last modified the inode in. The biggest cool part of this is that it requires no changes to the recovery code, so if you fsync with this patch and crash and load an old kernel, it will run the recovery and be a-ok. I have tested this pretty thoroughly with an fsync tester and everything comes back fine, as well as xfstests. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2011-08-01Btrfs: clean up code for merging extent mapsLi Zefan
unpin_extent_cache() and add_extent_mapping() shares the same code that merges extent maps. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>