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2011-06-17Btrfs: avoid delayed metadata items during commitsChris Mason
Snapshot creation has two phases. One is the initial snapshot setup, and the second is done during commit, while nobody is allowed to modify the root we are snapshotting. The delayed metadata insertion code can break that rule, it does a delayed inode update on the inode of the parent of the snapshot, and delayed directory item insertion. This makes sure to run the pending delayed operations before we record the snapshot root, which avoids corruptions. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-17Merge branch 'for-chris' of ↵Chris Mason
git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-work into for-linus Conflicts: fs/btrfs/transaction.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-17Btrfs: fix relocation racesChris Mason
The recent commit to get rid of our trans_mutex introduced some races with block group relocation. The problem is that relocation needs to do some record keeping about each root, and it was relying on the transaction mutex to coordinate things in subtle ways. This fix adds a mutex just for the relocation code and makes sure it doesn't have a big impact on normal operations. The race is really fixed in btrfs_record_root_in_trans, which is where we step back and wait for the relocation code to finish accounting setup. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-15Btrfs: set no_trans_join after trying to expand the transactionJosef Bacik
We can lockup if we try to allow new writers join the transaction and we have flushoncommit set or have a pending snapshot. This is because we set no_trans_join and then loop around and try to wait for ordered extents again. The problem is the ordered endio stuff needs to join the transaction, which it can't do because no_trans_join is set. So instead wait until after this loop to set no_trans_join and then make sure to wait for num_writers == 1 in case anybody got started in between us exiting the loop and setting no_trans_join. This could easily be reproduced by mounting -o flushoncommit and running xfstest 13. It cannot be reproduced with this patch. Thanks, Reported-by: Jim Schutt <jaschut@sandia.gov> Signed-off-by: Josef Bacik <josef@redhat.com>
2011-06-10Btrfs: clear current->journal_info on async transaction commitSage Weil
Normally current->jouranl_info is cleared by commit_transaction. For an async snap or subvol creation, though, it runs in a work queue. Clear it in btrfs_commit_transaction_async() to avoid leaking a non-NULL journal_info when we return to userspace. When the actual commit runs in the other thread it won't care that it's current->journal_info is already NULL. Signed-off-by: Sage Weil <sage@newdream.net> Tested-by: Jim Schutt <jaschut@sandia.gov> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-09Btrfs: unlock the trans lock properlyJosef Bacik
In btrfs_wait_for_commit if we came upon a transaction that had committed we just exited, but that's bad since we are holding the trans_lock. So break instead so that the lock is dropped. Thanks, Reported-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com>
2011-06-04btrfs: add helper for fs_info->closingDavid Sterba
wrap checking of filesystem 'closing' flag and fix a few missing memory barriers. Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-28Merge branch 'for-chris' ofChris Mason
git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-work into for-linus Conflicts: fs/btrfs/disk-io.c fs/btrfs/extent-tree.c fs/btrfs/free-space-cache.c fs/btrfs/inode.c fs/btrfs/transaction.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-23Btrfs: kill BTRFS_I(inode)->block_groupJosef Bacik
Originally this was going to be used as a way to give hints to the allocator, but frankly we can get much better hints elsewhere and it's not even used at all for anything usefull. In addition to be completely useless, when we initialize an inode we try and find a freeish block group to set as the inodes block group, and with a completely full 40gb fs this takes _forever_, so I imagine with say 1tb fs this is just unbearable. So just axe the thing altoghether, we don't need it and it saves us 8 bytes in the inode and saves us 500 microseconds per inode lookup in my testcase. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-05-23Btrfs: kill trans_mutexJosef Bacik
We use trans_mutex for lots of things, here's a basic list 1) To serialize trans_handles joining the currently running transaction 2) To make sure that no new trans handles are started while we are committing 3) To protect the dead_roots list and the transaction lists Really the serializing trans_handles joining is not too hard, and can really get bogged down in acquiring a reference to the transaction. So replace the trans_mutex with a trans_lock spinlock and use it to do the following 1) Protect fs_info->running_transaction. All trans handles have to do is check this, and then take a reference of the transaction and keep on going. 2) Protect the fs_info->trans_list. This doesn't get used too much, basically it just holds the current transactions, which will usually just be the currently committing transaction and the currently running transaction at most. 3) Protect the dead roots list. This is only ever processed by splicing the list so this is relatively simple. 4) Protect the fs_info->reloc_ctl stuff. This is very lightweight and was using the trans_mutex before, so this is a pretty straightforward change. 5) Protect fs_info->no_trans_join. Because we don't hold the trans_lock over the entirety of the commit we need to have a way to block new people from creating a new transaction while we're doing our work. So we set no_trans_join and in join_transaction we test to see if that is set, and if it is we do a wait_on_commit. 6) Make the transaction use count atomic so we don't need to take locks to modify it when we're dropping references. 7) Add a commit_lock to the transaction to make sure multiple people trying to commit the same transaction don't race and commit at the same time. 8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl trans. I have tested this with xfstests, but obviously it is a pretty hairy change so lots of testing is greatly appreciated. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-05-23Btrfs: if we've already started a trans handle, use that oneJosef Bacik
We currently track trans handles in current->journal_info, but we don't actually use it. This patch fixes it. This will cover the case where we have multiple people starting transactions down the call chain. This keeps us from having to allocate a new handle and all of that, we just increase the use count of the current handle, save the old block_rsv, and return. I tested this with xfstests and it worked out fine. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-05-23Btrfs: take away the num_items argument from btrfs_join_transactionJosef Bacik
I keep forgetting that btrfs_join_transaction() just ignores the num_items argument, which leads me to sending pointless patches and looking stupid :). So just kill the num_items argument from btrfs_join_transaction and btrfs_start_ioctl_transaction, since neither of them use it. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-05-23Merge branch 'for-chris' of ↵Chris Mason
git://git.kernel.org/pub/scm/linux/kernel/git/arne/btrfs-unstable-arne into inode_numbers Conflicts: fs/btrfs/Makefile fs/btrfs/ctree.h fs/btrfs/volumes.h Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-22Merge branch 'cleanups' of git://repo.or.cz/linux-2.6/btrfs-unstable into ↵Chris Mason
inode_numbers Conflicts: fs/btrfs/extent-tree.c fs/btrfs/free-space-cache.c fs/btrfs/inode.c fs/btrfs/tree-log.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-22Merge branch 'delayed_inode' into inode_numbersChris Mason
Conflicts: fs/btrfs/inode.c fs/btrfs/ioctl.c fs/btrfs/transaction.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-21btrfs: implement delayed inode items operationMiao Xie
Changelog V5 -> V6: - Fix oom when the memory load is high, by storing the delayed nodes into the root's radix tree, and letting btrfs inodes go. Changelog V4 -> V5: - Fix the race on adding the delayed node to the inode, which is spotted by Chris Mason. - Merge Chris Mason's incremental patch into this patch. - Fix deadlock between readdir() and memory fault, which is reported by Itaru Kitayama. Changelog V3 -> V4: - Fix nested lock, which is reported by Itaru Kitayama, by updating space cache inode in time. Changelog V2 -> V3: - Fix the race between the delayed worker and the task which does delayed items balance, which is reported by Tsutomu Itoh. - Modify the patch address David Sterba's comment. - Fix the bug of the cpu recursion spinlock, reported by Chris Mason Changelog V1 -> V2: - break up the global rb-tree, use a list to manage the delayed nodes, which is created for every directory and file, and used to manage the delayed directory name index items and the delayed inode item. - introduce a worker to deal with the delayed nodes. Compare with Ext3/4, the performance of file creation and deletion on btrfs is very poor. the reason is that btrfs must do a lot of b+ tree insertions, such as inode item, directory name item, directory name index and so on. If we can do some delayed b+ tree insertion or deletion, we can improve the performance, so we made this patch which implemented delayed directory name index insertion/deletion and delayed inode update. Implementation: - introduce a delayed root object into the filesystem, that use two lists to manage the delayed nodes which are created for every file/directory. One is used to manage all the delayed nodes that have delayed items. And the other is used to manage the delayed nodes which is waiting to be dealt with by the work thread. - Every delayed node has two rb-tree, one is used to manage the directory name index which is going to be inserted into b+ tree, and the other is used to manage the directory name index which is going to be deleted from b+ tree. - introduce a worker to deal with the delayed operation. This worker is used to deal with the works of the delayed directory name index items insertion and deletion and the delayed inode update. When the delayed items is beyond the lower limit, we create works for some delayed nodes and insert them into the work queue of the worker, and then go back. When the delayed items is beyond the upper bound, we create works for all the delayed nodes that haven't been dealt with, and insert them into the work queue of the worker, and then wait for that the untreated items is below some threshold value. - When we want to insert a directory name index into b+ tree, we just add the information into the delayed inserting rb-tree. And then we check the number of the delayed items and do delayed items balance. (The balance policy is above.) - When we want to delete a directory name index from the b+ tree, we search it in the inserting rb-tree at first. If we look it up, just drop it. If not, add the key of it into the delayed deleting rb-tree. Similar to the delayed inserting rb-tree, we also check the number of the delayed items and do delayed items balance. (The same to inserting manipulation) - When we want to update the metadata of some inode, we cached the data of the inode into the delayed node. the worker will flush it into the b+ tree after dealing with the delayed insertion and deletion. - We will move the delayed node to the tail of the list after we access the delayed node, By this way, we can cache more delayed items and merge more inode updates. - If we want to commit transaction, we will deal with all the delayed node. - the delayed node will be freed when we free the btrfs inode. - Before we log the inode items, we commit all the directory name index items and the delayed inode update. I did a quick test by the benchmark tool[1] and found we can improve the performance of file creation by ~15%, and file deletion by ~20%. Before applying this patch: Create files: Total files: 50000 Total time: 1.096108 Average time: 0.000022 Delete files: Total files: 50000 Total time: 1.510403 Average time: 0.000030 After applying this patch: Create files: Total files: 50000 Total time: 0.932899 Average time: 0.000019 Delete files: Total files: 50000 Total time: 1.215732 Average time: 0.000024 [1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3 Many thanks for Kitayama-san's help! Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Reviewed-by: David Sterba <dave@jikos.cz> Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Tested-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-12btrfs: scrubArne Jansen
This adds an initial implementation for scrub. It works quite straightforward. The usermode issues an ioctl for each device in the fs. For each device, it enumerates the allocated device chunks. For each chunk, the contained extents are enumerated and the data checksums fetched. The extents are read sequentially and the checksums verified. If an error occurs (checksum or EIO), a good copy is searched for. If one is found, the bad copy will be rewritten. All enumerations happen from the commit roots. During a transaction commit, the scrubs get paused and afterwards continue from the new roots. This commit is based on the series originally posted to linux-btrfs with some improvements that resulted from comments from David Sterba, Ilya Dryomov and Jan Schmidt. Signed-off-by: Arne Jansen <sensille@gmx.net>
2011-05-06btrfs: remove old unused commented out codeDavid Sterba
Remove code which has been #if0-ed out for a very long time and does not seem to be related to current codebase anymore. Signed-off-by: David Sterba <dsterba@suse.cz>
2011-05-02btrfs: drop unused argument from extent_io_tree_initDavid Sterba
all callers pass GFP_NOFS, but the GFP mask argument is not used in the function; GFP_ATOMIC is passed to radix tree initialization and it's the only correct one, since we're using the preload/insert mechanism of radix tree. Let's drop the gfp mask from btrfs function, this will not change behaviour. Signed-off-by: David Sterba <dsterba@suse.cz>
2011-04-25Btrfs: Support reading/writing on disk free ino cacheLi Zefan
This is similar to block group caching. We dedicate a special inode in fs tree to save free ino cache. At the very first time we create/delete a file after mount, the free ino cache will be loaded from disk into memory. When the fs tree is commited, the cache will be written back to disk. To keep compatibility, we check the root generation against the generation of the special inode when loading the cache, so the loading will fail if the btrfs filesystem was mounted in an older kernel before. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-25Btrfs: Always use 64bit inode numberLi Zefan
There's a potential problem in 32bit system when we exhaust 32bit inode numbers and start to allocate big inode numbers, because btrfs uses inode->i_ino in many places. So here we always use BTRFS_I(inode)->location.objectid, which is an u64 variable. There are 2 exceptions that BTRFS_I(inode)->location.objectid != inode->i_ino: the btree inode (0 vs 1) and empty subvol dirs (256 vs 2), and inode->i_ino will be used in those cases. Another reason to make this change is I'm going to use a special inode to save free ino cache, and the inode number must be > (u64)-256. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-25Btrfs: Cache free inode numbers in memoryLi Zefan
Currently btrfs stores the highest objectid of the fs tree, and it always returns (highest+1) inode number when we create a file, so inode numbers won't be reclaimed when we delete files, so we'll run out of inode numbers as we keep create/delete files in 32bits machines. This fixes it, and it works similarly to how we cache free space in block cgroups. We start a kernel thread to read the file tree. By scanning inode items, we know which chunks of inode numbers are free, and we cache them in an rb-tree. Because we are searching the commit root, we have to carefully handle the cross-transaction case. The rb-tree is a hybrid extent+bitmap tree, so if we have too many small chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram of extents, and a bitmap will be used if we exceed this threshold. The extents threshold is adjusted in runtime. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-04-11Btrfs: avoid taking the trans_mutex in btrfs_end_transactionJosef Bacik
I've been working on making our O_DIRECT latency not suck and I noticed we were taking the trans_mutex in btrfs_end_transaction. So to do this we convert num_writers and use_count to atomic_t's and just decrement them in btrfs_end_transaction. Instead of deleting the transaction from the trans list in put_transaction we do that in btrfs_commit_transaction() since that's the only time it actually needs to be removed from the list. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-08Btrfs: only retry transaction reservation onceJosef Bacik
I saw a lockup where we kept getting into this start transaction->commit transaction loop because of enospce. The fact is if we fail to make our reservation, we've tried _everything_ several times, so we only need to try and commit the transaction once, and if that doesn't work then we really are out of space and need to just exit. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2011-04-05Btrfs: Fix uninitialized root flags for subvolumesLi Zefan
root_item->flags and root_item->byte_limit are not initialized when a subvolume is created. This bug is not revealed until we added readonly snapshot support - now you mount a btrfs filesystem and you may find the subvolumes in it are readonly. To work around this problem, we steal a bit from root_item->inode_item->flags, and use it to indicate if those fields have been properly initialized. When we read a tree root from disk, we check if the bit is set, and if not we'll set the flag and initialize the two fields of the root item. Reported-by: Andreas Philipp <philipp.andreas@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Tested-by: Andreas Philipp <philipp.andreas@gmail.com> cc: stable@kernel.org Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-05Btrfs: fix memory leak in start_transaction()Yoshinori Sano
Free btrfs_trans_handle when join_transaction() fails in start_transaction() Signed-off-by: Yoshinori Sano <yoshinori.sano@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-03-28Btrfs: cleanup some BUG_ON()Tsutomu Itoh
This patch changes some BUG_ON() to the error return. (but, most callers still use BUG_ON()) Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-03-28Btrfs: add initial tracepoint support for btrfsliubo
Tracepoints can provide insight into why btrfs hits bugs and be greatly helpful for debugging, e.g dd-7822 [000] 2121.641088: btrfs_inode_request: root = 5(FS_TREE), gen = 4, ino = 256, blocks = 8, disk_i_size = 0, last_trans = 8, logged_trans = 0 dd-7822 [000] 2121.641100: btrfs_inode_new: root = 5(FS_TREE), gen = 8, ino = 257, blocks = 0, disk_i_size = 0, last_trans = 0, logged_trans = 0 btrfs-transacti-7804 [001] 2146.935420: btrfs_cow_block: root = 2(EXTENT_TREE), refs = 2, orig_buf = 29368320 (orig_level = 0), cow_buf = 29388800 (cow_level = 0) btrfs-transacti-7804 [001] 2146.935473: btrfs_cow_block: root = 1(ROOT_TREE), refs = 2, orig_buf = 29364224 (orig_level = 0), cow_buf = 29392896 (cow_level = 0) btrfs-transacti-7804 [001] 2146.972221: btrfs_transaction_commit: root = 1(ROOT_TREE), gen = 8 flush-btrfs-2-7821 [001] 2155.824210: btrfs_chunk_alloc: root = 3(CHUNK_TREE), offset = 1103101952, size = 1073741824, num_stripes = 1, sub_stripes = 0, type = DATA flush-btrfs-2-7821 [001] 2155.824241: btrfs_cow_block: root = 2(EXTENT_TREE), refs = 2, orig_buf = 29388800 (orig_level = 0), cow_buf = 29396992 (cow_level = 0) flush-btrfs-2-7821 [001] 2155.824255: btrfs_cow_block: root = 4(DEV_TREE), refs = 2, orig_buf = 29372416 (orig_level = 0), cow_buf = 29401088 (cow_level = 0) flush-btrfs-2-7821 [000] 2155.824329: btrfs_cow_block: root = 3(CHUNK_TREE), refs = 2, orig_buf = 20971520 (orig_level = 0), cow_buf = 20975616 (cow_level = 0) btrfs-endio-wri-7800 [001] 2155.898019: btrfs_cow_block: root = 5(FS_TREE), refs = 2, orig_buf = 29384704 (orig_level = 0), cow_buf = 29405184 (cow_level = 0) btrfs-endio-wri-7800 [001] 2155.898043: btrfs_cow_block: root = 7(CSUM_TREE), refs = 2, orig_buf = 29376512 (orig_level = 0), cow_buf = 29409280 (cow_level = 0) Here is what I have added: 1) ordere_extent: btrfs_ordered_extent_add btrfs_ordered_extent_remove btrfs_ordered_extent_start btrfs_ordered_extent_put These provide critical information to understand how ordered_extents are updated. 2) extent_map: btrfs_get_extent extent_map is used in both read and write cases, and it is useful for tracking how btrfs specific IO is running. 3) writepage: __extent_writepage btrfs_writepage_end_io_hook Pages are cirtical resourses and produce a lot of corner cases during writeback, so it is valuable to know how page is written to disk. 4) inode: btrfs_inode_new btrfs_inode_request btrfs_inode_evict These can show where and when a inode is created, when a inode is evicted. 5) sync: btrfs_sync_file btrfs_sync_fs These show sync arguments. 6) transaction: btrfs_transaction_commit In transaction based filesystem, it will be useful to know the generation and who does commit. 7) back reference and cow: btrfs_delayed_tree_ref btrfs_delayed_data_ref btrfs_delayed_ref_head btrfs_cow_block Btrfs natively supports back references, these tracepoints are helpful on understanding btrfs's COW mechanism. 8) chunk: btrfs_chunk_alloc btrfs_chunk_free Chunk is a link between physical offset and logical offset, and stands for space infomation in btrfs, and these are helpful on tracing space things. 9) reserved_extent: btrfs_reserved_extent_alloc btrfs_reserved_extent_free These can show how btrfs uses its space. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-01-28btrfs: fix return value check of btrfs_join_transaction()Tsutomu Itoh
The error check of btrfs_join_transaction()/btrfs_join_transaction_nolock() is added, and the mistake of the error check in several places is corrected. For more stable Btrfs, I think that we should reduce BUG_ON(). But, I think that long time is necessary for this. So, I propose this patch as a short-term solution. With this patch: - To more stable Btrfs, the part that should be corrected is clarified. - The panic isn't done by the NULL pointer reference etc. (even if BUG_ON() is increased temporarily) - The error code is returned in the place where the error can be easily returned. As a long-term plan: - BUG_ON() is reduced by using the forced-readonly framework, etc. Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-01-17Btrfs: forced readonly mounts on errorsliubo
This patch comes from "Forced readonly mounts on errors" ideas. As we know, this is the first step in being more fault tolerant of disk corruptions instead of just using BUG() statements. The major content: - add a framework for generating errors that should result in filesystems going readonly. - keep FS state in disk super block. - make sure that all of resource will be freed and released at umount time. - make sure that fter FS is forced readonly on error, there will be no more disk change before FS is corrected. For this, we should stop write operation. After this patch is applied, the conversion from BUG() to such a framework can happen incrementally. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-12-23Btrfs: Add readonly snapshots supportLi Zefan
Usage: Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and call ioctl(BTRFS_I0CTL_SNAP_CREATE_V2). Implementation: - Set readonly bit of btrfs_root_item->flags. - Add readonly checks in btrfs_permission (inode_permission), btrfs_setattr, btrfs_set/remove_xattr and some ioctls. Changelog for v3: - Eliminate btrfs_root->readonly, but check btrfs_root->root_item.flags. - Rename BTRFS_ROOT_SNAP_RDONLY to BTRFS_ROOT_SUBVOL_RDONLY. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2010-11-21Btrfs: use dget_parent where we can UPDATEDJosef Bacik
There are lots of places where we do dentry->d_parent->d_inode without holding the dentry->d_lock. This could cause problems with rename. So instead we need to use dget_parent() and hold the reference to the parent as long as we are going to use it's inode and then dput it at the end. Signed-off-by: Josef Bacik <josef@redhat.com> Cc: raven@themaw.net Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29Btrfs: add START_SYNC, WAIT_SYNC ioctlsSage Weil
START_SYNC will start a sync/commit, but not wait for it to complete. Any modification started after the ioctl returns is guaranteed not to be included in the commit. If a non-NULL pointer is passed, the transaction id will be returned to userspace. WAIT_SYNC will wait for any in-progress commit to complete. If a transaction id is specified, the ioctl will block and then return (success) when the specified transaction has committed. If it has already committed when we call the ioctl, it returns immediately. If the specified transaction doesn't exist, it returns EINVAL. If no transaction id is specified, WAIT_SYNC will wait for the currently committing transaction to finish it's commit to disk. If there is no currently committing transaction, it returns success. These ioctls are useful for applications which want to impose an ordering on when fs modifications reach disk, but do not want to wait for the full (slow) commit process to do so. Picky callers can take the transid returned by START_SYNC and feed it to WAIT_SYNC, and be certain to wait only as long as necessary for the transaction _they_ started to reach disk. Sloppy callers can START_SYNC and WAIT_SYNC without a transid, and provided they didn't wait too long between the calls, they will get the same result. However, if a second commit starts before they call WAIT_SYNC, they may end up waiting longer for it to commit as well. Even so, a START_SYNC+WAIT_SYNC still guarantees that any operation completed before the START_SYNC reaches disk. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29Btrfs: async transaction commitSage Weil
Add support for an async transaction commit that is ordered such that any subsequent operations will join the following transaction, but does not wait until the current commit is fully on disk. This avoids much of the latency associated with the btrfs_commit_transaction for callers concerned with serialization and not safety. The wait_for_unblock flag controls whether we wait for the 'middle' portion of commit_transaction to complete, which is necessary if the caller expects some of the modifications contained in the commit to be available (this is the case for subvol/snapshot creation). Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29Btrfs: fix deadlock in btrfs_commit_transactionSage Weil
We calculate timeout (either 1 or MAX_SCHEDULE_TIMEOUT) based on whether num_writers > 1 or should_grow at the top of the loop. Then, much much later, we wait for that timeout if either num_writers or should_grow is true. However, it's possible for a racing process (calling btrfs_end_transaction()) to decrement num_writers such that we wait forever instead of for 1. Fix this by deciding how long to wait when we wait. Include a smp_mb() before checking if the waitqueue is active to ensure the num_writers is visible. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-29Merge branch 'bug-fixes' of ↵Chris Mason
git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-work Conflicts: fs/btrfs/extent-tree.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-10-28Btrfs: create special free space cache inodeJosef Bacik
In order to save free space cache, we need an inode to hold the data, and we need a special item to point at the right inode for the right block group. So first, create a special item that will point to the right inode, and the number of extent entries we will have and the number of bitmaps we will have. We truncate and pre-allocate space everytime to make sure it's uptodate. This feature will be turned on as soon as you mount with -o space_cache, however it is safe to boot into old kernels, they will just generate the cache the old fashion way. When you boot back into a newer kernel we will notice that we modified and not the cache and automatically discard the cache. Signed-off-by: Josef Bacik <josef@redhat.com>
2010-10-22Btrfs: rework how we reserve metadata bytesJosef Bacik
With multi-threaded writes we were getting ENOSPC early because somebody would come in, start flushing delalloc because they couldn't make their reservation, and in the meantime other threads would come in and use the space that was getting freed up, so when the original thread went to check to see if they had space they didn't and they'd return ENOSPC. So instead if we have some free space but not enough for our reservation, take the reservation and then start doing the flushing. The only time we don't take reservations is when we've already overcommitted our space, that way we don't have people who come late to the party way overcommitting ourselves. This also moves all of the retrying and flushing code into reserve_metdata_bytes so it's all uniform. This keeps my fs_mark test from returning -ENOSPC as soon as it starts and actually lets me fill up the disk. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2010-05-25Btrfs: don't walk around with task->state != TASK_RUNNINGChris Mason
Yan Zheng noticed two places we were doing a lot of work without task->state set to TASK_RUNNING. This sets the state properly after we get ready to sleep but decide not to. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25Btrfs: Metadata ENOSPC handling for balanceYan, Zheng
This patch adds metadata ENOSPC handling for the balance code. It is consisted by following major changes: 1. Avoid COW tree leave in the phrase of merging tree. 2. Handle interaction with snapshot creation. 3. make the backref cache can live across transactions. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25Btrfs: Metadata reservation for orphan inodesYan, Zheng
reserve metadata space for handling orphan inodes Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25Btrfs: Introduce global metadata reservationYan, Zheng
Reserve metadata space for extent tree, checksum tree and root tree Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25Btrfs: Integrate metadata reservation with start_transactionYan, Zheng
Besides simplify the code, this change makes sure all metadata reservation for normal metadata operations are released after committing transaction. Changes since V1: Add code that check if unlink and rmdir will free space. Add ENOSPC handling for clone ioctl. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-05-25Btrfs: Introduce contexts for metadata reservationYan, Zheng
Introducing metadata reseravtion contexts has two major advantages. First, it makes metadata reseravtion more traceable. Second, it can reclaim freed space and re-add them to the itself after transaction committed. Besides add btrfs_block_rsv structure and related helper functions, This patch contains following changes: Move code that decides if freed tree block should be pinned into btrfs_free_tree_block(). Make space accounting more accurate, mainly for handling read only block groups. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: Btrfs: add check for changed leaves in setup_leaf_for_split Btrfs: create snapshot references in same commit as snapshot Btrfs: fix small race with delalloc flushing waitqueue's Btrfs: use add_to_page_cache_lru, use __page_cache_alloc Btrfs: fix chunk allocate size calculation Btrfs: kill max_extent mount option Btrfs: fail to mount if we have problems reading the block groups Btrfs: check btrfs_get_extent return for IS_ERR() Btrfs: handle kmalloc() failure in inode lookup ioctl Btrfs: dereferencing freed memory Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk() Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree() Btrfs: Remove unnecessary finish_wait() in wait_current_trans() Btrfs: add NULL check for do_walk_down() Btrfs: remove duplicate include in ioctl.c Fix trivial conflict in fs/btrfs/compression.c due to slab.h include cleanups.
2010-04-05Btrfs: create snapshot references in same commit as snapshotSage Weil
This creates the reference to a new snapshot in the same commit as the snapshot itself. This avoids the need for a second commit in order for a snapshot to be persistent, and also avoids the problem of "leaking" a new snapshot tree root if the host crashes before the second commit takes place. It is not at all clear to me why it wasn't always done this way. If there is still a reason for the two-stage {create,finish}_pending_snapshots() approach I'm missing something! :) I've been running this for a couple weeks under pretty heavy usage (a few snapshots per minute) without obvious problems. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: Remove unnecessary finish_wait() in wait_current_trans()Zhao Lei
We only need to call finish_wait() after wait loop. By the way, this patch makes code of waiting loop similar to example in wait.h(no functional change) Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-15Btrfs: flush data on snapshot creationSage Weil
Flush any delalloc extents when we create a snapshot, so that recently written file data is always included in the snapshot. A later commit will add the ability to snapshot without the flush, but most people expect flushing. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-08Btrfs: use RB_ROOT to intialize rb_trees instead of setting rb_node to NULLEric Paris
btrfs inialize rb trees in quite a number of places by settin rb_node = NULL; The problem with this is that 17d9ddc72fb8bba0d4f678 in the linux-next tree adds a new field to that struct which needs to be NULL for the new rbtree library code to work properly. This patch uses RB_ROOT as the intializer so all of the relevant fields will be NULL'd. Without the patch I get a panic. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>