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2012-07-25Merge branch 'send-v2' of git://github.com/ablock84/linux-btrfs into for-linusChris Mason
This is the kernel portion of btrfs send/receive Conflicts: fs/btrfs/Makefile fs/btrfs/backref.h fs/btrfs/ctree.c fs/btrfs/ioctl.c fs/btrfs/ioctl.h Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-07-25Btrfs: add btrfs_compare_trees functionAlexander Block
This function is used to find the differences between two trees. The tree compare skips whole subtrees if it detects shared tree blocks and thus is pretty fast. Signed-off-by: Alexander Block <ablock84@googlemail.com> Reviewed-by: David Sterba <dave@jikos.cz> Reviewed-by: Arne Jansen <sensille@gmx.net> Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Reviewed-by: Alex Lyakas <alex.bolshoy.btrfs@gmail.com>
2012-07-25Btrfs: add helper for tree enumerationArne Jansen
Often no exact match is wanted but just the next lower or higher item. There's a lot of duplicated code throughout btrfs to deal with the corner cases. This patch adds a helper function that can facilitate searching. Signed-off-by: Arne Jansen <sensille@gmx.net>
2012-07-10Btrfs: add helper for tree enumerationArne Jansen
Often no exact match is wanted but just the next lower or higher item. There's a lot of duplicated code throughout btrfs to deal with the corner cases. This patch adds a helper function that can facilitate searching. Signed-off-by: Arne Jansen <sensille@gmx.net>
2012-07-10Btrfs: join tree mod log code with the code holding back delayed refsJan Schmidt
We've got two mechanisms both required for reliable backref resolving (tree mod log and holding back delayed refs). You cannot make use of one without the other. So instead of requiring the user of this mechanism to setup both correctly, we join them into a single interface. Additionally, we stop inserting non-blockers into fs_info->tree_mod_seq_list as we did before, which was of no value. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-07-10Btrfs: fix buffer leak in btrfs_next_old_leafJan Schmidt
When calling btrfs_next_old_leaf, we were leaking an extent buffer in the rare case of using the deadlock avoidance code needed for the tree mod log. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-27Btrfs: resolve tree mod log locking issue in btrfs_next_leafJan Schmidt
With the tree mod log, we may end up with two roots (the current root and a rewinded version of it) both pointing to two leaves, l1 and l2, of which l2 had already been cow-ed in the current transaction. If we don't rewind any tree blocks, we cannot have two roots both pointing to an already cowed tree block. Now there is btrfs_next_leaf, which has a leaf locked and wants a lock on the next (right) leaf. And there is push_leaf_left, which has a (cowed!) leaf locked and wants a lock on the previous (left) leaf. In order to solve this dead lock situation, we use try_lock in btrfs_next_leaf (only in case it's called with a tree mod log time_seq paramter) and if we fail to get a lock on the next leaf, we give up our lock on the current leaf and retry from the very beginning. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-27Btrfs: fix tree mod log rewind of ADD operationsJan Schmidt
When a MOD_LOG_KEY_ADD operation is rewinded, we remove the key from the tree block. If its not the last key, removal involves a move operation. This move operation was explicitly done before this commit. However, at insertion time, there's a move operation before the actual addition to make room for the new key, which is recorded in the tree mod log as well. This means, we must drop the move operation when rewinding the add operation, because the next operation we'll be rewinding will be the corresponding MOD_LOG_MOVE_KEYS operation. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-27Btrfs: always put insert_ptr modifications into the tree mod logJan Schmidt
Several callers of insert_ptr set the tree_mod_log parameter to 0 to avoid addition to the tree mod log. In fact, we need all of those operations. This commit simply removes the additional parameter and makes addition to the tree mod log unconditional. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-27Btrfs: fix tree mod log for root replacements at leaf levelJan Schmidt
For the tree mod log, we don't log any operations at leaf level. If the root is at the leaf level (i.e. the tree consists only of the root), then __tree_mod_log_oldest_root will find a ROOT_REPLACE operation in the log (because we always log that one no matter which level), but no other operations. With this patch __tree_mod_log_oldest_root exits cleanly instead of BUGging in this situation. get_old_root checks if its really a root at leaf level in case we don't have any operations and WARNs if this assumption breaks. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-15Btrfs: init old_generation in get_old_rootChris Mason
gcc was giving an uninit variable warning here. Strictly speaking we don't need to init it, but this will make things much less error prone. Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-06-14Btrfs: fix race in tree mod log additionJan Schmidt
When adding to the tree modification log, we grab two locks at different stages. We must not drop the outer lock until we're done with section protected by the inner lock. This moves the unlock call for the outer lock to the appropriate position. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-14Btrfs: add btrfs_next_old_leafJan Schmidt
To make sense of the tree mod log, the backref walker not only needs btrfs_search_old_slot, but it also called btrfs_next_leaf, which in turn was calling btrfs_search_slot. This obviously didn't give the correct result. This commit adds btrfs_next_old_leaf, a drop-in replacement for btrfs_next_leaf with a time_seq parameter. If it is zero, it behaves exactly like btrfs_next_leaf. If it is non-zero, it will use btrfs_search_old_slot with this time_seq parameter. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-14Btrfs: fix return value for __tree_mod_log_oldest_rootJan Schmidt
In __tree_mod_log_oldest_root() we must return the found operation even if it's not a ROOT_REPLACE operation. Otherwise, the caller assumes that there are no operations to be rewinded and returns immediately. The code in the caller is modified to improve readability. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-14Btrfs: use btrfs_read_lock_root_node in get_old_rootJan Schmidt
get_old_root could race with root node updates because we weren't locking the node early enough. Use btrfs_read_lock_root_node to grab the root locked in the very beginning and release the lock as soon as possible (just like btrfs_search_slot does). Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-06-04Btrfs: remove call to btrfs_header_nritems with no effectJan Schmidt
This is a leftover from cleanup patch 559af821. Before the cleanup, btrfs_header_nritems was called inside an if condition. As it has no side effects we need to preserve here, it should simply be dropped. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-31Merge branch 'for-chris' of git://git.jan-o-sch.net/btrfs-unstable into ↵Chris Mason
for-linus Conflicts: fs/btrfs/ulist.h Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-05-31Btrfs: fix tree mod log rewinded level and rewinding of moved keysJan Schmidt
When we rewind REMOVE_WHILE_FREEING operations, there's code that allocates a fresh buffer instead of cloning the old one. Setting that buffer's level correctly was missing in this case. When rewinding a MOVE_KEYS operation, btrfs_node_key_ptr_offset(slot) was missing for memmove_extent_buffer()'s arguments. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-31Btrfs: fix tree mod log del_ptrJan Schmidt
Logging for del_ptr when we're not deleting the last pointer was wrong. This fixes both, duplicate log entries and log sequence. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-31Btrfs: add tree_mod_dont_log helperJan Schmidt
Replace duplicate code by small inline helper function. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-31Btrfs: add missing spin_lock for insertion into tree mod logJan Schmidt
tree_mod_alloc calls __get_tree_mod_seq and must acquire a spinlock before doing so. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-30Btrfs: return value of btrfs_read_buffer is checked correctlyTsutomu Itoh
btrfs_read_buffer() has the possibility of returning the error. Therefore, I add the code in which the return value of btrfs_read_buffer() is checked. Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
2012-05-30Btrfs: add btrfs_search_old_slotJan Schmidt
The tree modification log together with the current state of the tree gives a consistent, old version of the tree. btrfs_search_old_slot is used to search through this old version and return old (dummy!) extent buffers. Naturally, this function cannot do any tree modifications. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-30Btrfs: add del_ptr and insert_ptr modifications to the tree mod logJan Schmidt
Record all relevant modifications to block pointers in the tree mod log so that we can rewind them later on for backref walking. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-30Btrfs: put all block modifications into the tree mod logJan Schmidt
When running functions that can make changes to the internal trees (e.g. btrfs_search_slot), we check if somebody may be interested in the block we're currently modifying. If so, we record our modification to be able to rewind it later on. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-30Btrfs: add tree modification log functionsJan Schmidt
The tree mod log will log modifications made fs-tree nodes. Most modifications are done by autobalance of the tree. Such changes are recorded as long as a block entry exists. When released, the log is cleaned. With the tree modification log, it's possible to reconstruct a consistent old state of the tree. This is required to do backref walking on a busy file system. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-26Btrfs: don't set for_cow parameter for tree block functionsJan Schmidt
Three callers of btrfs_free_tree_block or btrfs_alloc_tree_block passed parameter for_cow = 1. In fact, these two functions should never mark their tree modification operations as for_cow, because they can change the number of blocks referenced by a tree. Hence, we remove the extra for_cow parameter from these functions and make them pass a zero down. Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2012-05-11btrfs/ctree.c: remove the unnecessary 'return -1;' at the end of bin_searchWang Sheng-Hui
The code path should not reach there. Remove it. Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
2012-05-06Btrfs: avoid sleeping in verify_parent_transid while atomicChris Mason
verify_parent_transid needs to lock the extent range to make sure no IO is underway, and so it can safely clear the uptodate bits if our checks fail. But, a few callers are using it with spinlocks held. Most of the time, the generation numbers are going to match, and we don't want to switch to a blocking lock just for the error case. This adds an atomic flag to verify_parent_transid, and changes it to return EAGAIN if it needs to block to properly verifiy things. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-05-04Btrfs: Add properly locking around add_root_to_dirty_listChris Mason
add_root_to_dirty_list happens once at the very beginning of the transaction, but it is still racey. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-28Merge branch 'error-handling' into for-linusChris Mason
Conflicts: fs/btrfs/ctree.c fs/btrfs/disk-io.c fs/btrfs/extent-tree.c fs/btrfs/extent_io.c fs/btrfs/extent_io.h fs/btrfs/inode.c fs/btrfs/scrub.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26Btrfs: adjust the write_lock_level as we unlockChris Mason
btrfs_search_slot sometimes needs write locks on high levels of the tree. It remembers the highest level that needs a write lock and will use that for all future searches through the tree in a given call. But, very often we'll just cow the top level or the level below and we won't really need write locks on the root again after that. This patch changes things to adjust the write lock requirement as it unlocks levels. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26Btrfs: add the ability to cache a pointer into the ebChris Mason
This cuts down on the CPU time used by map_private_extent_buffer Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-03-26Btrfs: introduce free_extent_buffer_staleJosef Bacik
Because btrfs cow's we can end up with extent buffers that are no longer necessary just sitting around in memory. So instead of evicting these pages, we could end up evicting things we actually care about. Thus we have free_extent_buffer_stale for use when we are freeing tree blocks. This will make it so that the ref for the eb being in the radix tree is dropped as soon as possible and then is freed when the refcount hits 0 instead of waiting to be released by releasepage. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-03-22btrfs: replace many BUG_ONs with proper error handlingJeff Mahoney
btrfs currently handles most errors with BUG_ON. This patch is a work-in- progress but aims to handle most errors other than internal logic errors and ENOMEM more gracefully. This iteration prevents most crashes but can run into lockups with the page lock on occasion when the timing "works out." Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2012-03-22btrfs: Go readonly on tree errors in balance_levelMark Fasheh
balace_level() seems to deal with missing tree nodes by BUG_ON(). Instead, we can easily just set the file system readonly and bubble -EROFS back up the stack. Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2012-03-22btrfs: Don't BUG_ON errors from update_ref_for_cow()Mark Fasheh
__btrfs_cow_block(), the only caller of update_ref_for_cow() will BUG_ON() any error return. Instead, we can go read-only fs as update_ref_for_cow() manipulates disk data in a way which doesn't look like it's easily rolled back. Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22btrfs: Go readonly on bad extent refs in update_ref_for_cow()Mark Fasheh
update_ref_for_cow() will BUG_ON() after it's call to btrfs_lookup_extent_info() if no existing references are found. Since refs are computed directly from disk, this should be treated as a corruption instead of a logic error. Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22btrfs: Don't BUG_ON() errors in update_ref_for_cow()Mark Fasheh
The only caller of update_ref_for_cow() is __btrfs_cow_block() which was originally ignoring any return values. update_ref_for_cow() however doesn't look like a candidate to become a void function - there are a few places where errors can occur. So instead I changed update_ref_for_cow() to bubble all errors up (instead of BUG_ON). __btrfs_cow_block() was then updated to catch and BUG_ON() any errors from update_ref_for_cow(). The end effect is that we have no change in behavior, but about 8 different places where a BUG_ON(ret) was removed. Obviously a future patch will have to address the BUG_ON() in __btrfs_cow_block(). Signed-off-by: Mark Fasheh <mfasheh@suse.de>
2012-03-22btrfs: return void in functions without error conditionsJeff Mahoney
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
2011-12-22Btrfs: mark delayed refs as for cowArne Jansen
Add a for_cow parameter to add_delayed_*_ref and pass the appropriate value from every call site. The for_cow parameter will later on be used to determine if a ref will change anything with respect to qgroups. Delayed refs coming from relocation are always counted as for_cow, as they don't change subvol quota. Also pass in the fs_info for later use. btrfs_find_all_roots() will use this as an optimization, as changes that are for_cow will not change anything with respect to which root points to a certain leaf. Thus, we don't need to add the current sequence number to those delayed refs. Signed-off-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
2011-11-15Btrfs: fix tree corruption after multi-thread snapshots and inode_cache flushLiu Bo
The btrfs snapshotting code requires that once a root has been snapshotted, we don't change it during a commit. But there are two cases to lead to tree corruptions: 1) multi-thread snapshots can commit serveral snapshots in a transaction, and this may change the src root when processing the following pending snapshots, which lead to the former snapshots corruptions; 2) the free inode cache was changing the roots when it root the cache, which lead to corruptions. This fixes things by making sure we force COW the block after we create a snapshot during commiting a transaction, then any changes to the roots will result in COW, and we get all the fs roots and snapshot roots to be consistent. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-10-20Btrfs: fix array bound checkingLi Zefan
Otherwise we can execced the array bound of path->slots[]. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2011-07-27Btrfs: remove lockdep magic from btrfs_next_leafChris Mason
Before the reader/writer locks, btrfs_next_leaf needed to keep the path blocking to avoid making lockdep upset. Now that btrfs_next_leaf only takes read locks, this isn't required. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27Btrfs: switch the btrfs tree locks to reader/writerChris Mason
The btrfs metadata btree is the source of significant lock contention, especially in the root node. This commit changes our locking to use a reader/writer lock. The lock is built on top of rw spinlocks, and it extends the lock tracking to remember if we have a read lock or a write lock when we go to blocking. Atomics count the number of blocking readers or writers at any given time. It removes all of the adaptive spinning from the old code and uses only the spinning/blocking hints inside of btrfs to decide when it should continue spinning. In read heavy workloads this is dramatically faster. In write heavy workloads we're still faster because of less contention on the root node lock. We suffer slightly in dbench because we schedule more often during write locks, but all other benchmarks so far are improved. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-07-27Btrfs: stop using highmem for extent_buffersChris Mason
The extent_buffers have a very complex interface where we use HIGHMEM for metadata and try to cache a kmap mapping to access the memory. The next commit adds reader/writer locks, and concurrent use of this kmap cache would make it even more complex. This commit drops the ability to use HIGHMEM with extent buffers, and rips out all of the related code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-06-09Btrfs: don't map extent buffer if path->skip_locking is setJosef Bacik
Arne's scrub stuff exposed a problem with mapping the extent buffer in reada_for_search. He searches the commit root with multiple threads and with skip_locking set, so we can race and overwrite node->map_token since node isn't locked. So fix this so that we only map the extent buffer if we don't already have a map_token and skip_locking isn't set. Without this patch scrub would panic almost immediately, with the patch it doesn't panic anymore. Thanks, Reported-by: Arne Jansen <sensille@gmx.net> Signed-off-by: Josef Bacik <josef@redhat.com>
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>
2011-05-23Merge branch 'cleanups_and_fixes' into inode_numbersChris Mason
Conflicts: fs/btrfs/tree-log.c fs/btrfs/volumes.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-05-23Btrfs: BUG_ON is deleted from the caller of btrfs_truncate_item & ↵Tsutomu Itoh
btrfs_extend_item Currently, btrfs_truncate_item and btrfs_extend_item returns only 0. So, the check by BUG_ON in the caller is unnecessary. Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>