summaryrefslogtreecommitdiff
path: root/fs/xfs/libxfs/xfs_defer.h
AgeCommit message (Collapse)Author
2020-10-07xfs: fix an incore inode UAF in xfs_bui_recoverDarrick J. Wong
In xfs_bui_item_recover, there exists a use-after-free bug with regards to the inode that is involved in the bmap replay operation. If the mapping operation does not complete, we call xfs_bmap_unmap_extent to create a deferred op to finish the unmapping work, and we retain a pointer to the incore inode. Unfortunately, the very next thing we do is commit the transaction and drop the inode. If reclaim tears down the inode before we try to finish the defer ops, we dereference garbage and blow up. Therefore, create a way to join inodes to the defer ops freezer so that we can maintain the xfs_inode reference until we're done with the inode. Note: This imposes the requirement that there be enough memory to keep every incore inode in memory throughout recovery. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-10-07xfs: xfs_defer_capture should absorb remaining transaction reservationDarrick J. Wong
When xfs_defer_capture extracts the deferred ops and transaction state from a transaction, it should record the transaction reservation type from the old transaction so that when we continue the dfops chain, we still use the same reservation parameters. Doing this means that the log item recovery functions get to determine the transaction reservation instead of abusing tr_itruncate in yet another part of xfs. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-10-07xfs: xfs_defer_capture should absorb remaining block reservationsDarrick J. Wong
When xfs_defer_capture extracts the deferred ops and transaction state from a transaction, it should record the remaining block reservations so that when we continue the dfops chain, we can reserve the same number of blocks to use. We capture the reservations for both data and realtime volumes. This adds the requirement that every log intent item recovery function must be careful to reserve enough blocks to handle both itself and all defer ops that it can queue. On the other hand, this enables us to do away with the handwaving block estimation nonsense that was going on in xlog_finish_defer_ops. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-10-07xfs: proper replay of deferred ops queued during log recoveryDarrick J. Wong
When we replay unfinished intent items that have been recovered from the log, it's possible that the replay will cause the creation of more deferred work items. As outlined in commit 509955823cc9c ("xfs: log recovery should replay deferred ops in order"), later work items have an implicit ordering dependency on earlier work items. Therefore, recovery must replay the items (both recovered and created) in the same order that they would have been during normal operation. For log recovery, we enforce this ordering by using an empty transaction to collect deferred ops that get created in the process of recovering a log intent item to prevent them from being committed before the rest of the recovered intent items. After we finish committing all the recovered log items, we allocate a transaction with an enormous block reservation, splice our huge list of created deferred ops into that transaction, and commit it, thereby finishing all those ops. This is /really/ hokey -- it's the one place in XFS where we allow nested transactions; the splicing of the defer ops list is is inelegant and has to be done twice per recovery function; and the broken way we handle inode pointers and block reservations cause subtle use-after-free and allocator problems that will be fixed by this patch and the two patches after it. Therefore, replace the hokey empty transaction with a structure designed to capture each chain of deferred ops that are created as part of recovering a single unfinished log intent. Finally, refactor the loop that replays those chains to do so using one transaction per chain. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-09-23xfs: log new intent items created as part of finishing recovered intent itemsDarrick J. Wong
During a code inspection, I found a serious bug in the log intent item recovery code when an intent item cannot complete all the work and decides to requeue itself to get that done. When this happens, the item recovery creates a new incore deferred op representing the remaining work and attaches it to the transaction that it allocated. At the end of _item_recover, it moves the entire chain of deferred ops to the dummy parent_tp that xlog_recover_process_intents passed to it, but fail to log a new intent item for the remaining work before committing the transaction for the single unit of work. xlog_finish_defer_ops logs those new intent items once recovery has finished dealing with the intent items that it recovered, but this isn't sufficient. If the log is forced to disk after a recovered log item decides to requeue itself and the system goes down before we call xlog_finish_defer_ops, the second log recovery will never see the new intent item and therefore has no idea that there was more work to do. It will finish recovery leaving the filesystem in a corrupted state. The same logic applies to /any/ deferred ops added during intent item recovery, not just the one handling the remaining work. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-05-13xfs: Use the correct style for SPDX License IdentifierNishad Kamdar
This patch corrects the SPDX License Identifier style in header files related to XFS File System support. For C header files Documentation/process/license-rules.rst mandates C-like comments. (opposed to C source files where C++ style should be used). Changes made by using a script provided by Joe Perches here: https://lkml.org/lkml/2019/2/7/46. Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-04xfs: spell out the parameter name for ->cancel_itemChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-04xfs: use a xfs_btree_cur for the ->finish_cleanup stateChristoph Hellwig
Given how XFS is all based around btrees it doesn't make much sense to offer a totally generic state when we can just use the btree cursor. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-04xfs: turn dfp_done into a xfs_log_itemChristoph Hellwig
All defer op instance place their own extension of the log item into the dfp_done field. Replace that with a xfs_log_item to improve type safety and make the code easier to follow. Also use the opportunity to improve the ->finish_item calling conventions to place the done log item as the higher level structure before the list_entry used for the individual items. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-04xfs: turn dfp_intent into a xfs_log_itemChristoph Hellwig
All defer op instance place their own extension of the log item into the dfp_intent field. Replace that with a xfs_log_item to improve type safety and make the code easier to follow. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-04xfs: merge the ->diff_items defer op into ->create_intentChristoph Hellwig
This avoids a per-item indirect call, and also simplifies the interface a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-04xfs: merge the ->log_item defer op into ->create_intentChristoph Hellwig
These are aways called together, and my merging them we reduce the amount of indirect calls, improve type safety and in general clean up the code a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-12-12xfs: streamline defer op type handlingDarrick J. Wong
There's no need to bundle a pointer to the defer op type into the defer op control structure. Instead, store the defer op type enum, which enables us to shorten some of the lines. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2018-12-12xfs: idiotproof defer op type configurationDarrick J. Wong
Recently, we forgot to port a new defer op type to xfsprogs, which caused us some userspace pain. Reorganize the way we make libxfs clients supply defer op type information so that all type information has to be provided at build time instead of risky runtime dynamic configuration. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2018-08-02xfs: fold dfops into the transactionBrian Foster
struct xfs_defer_ops has now been reduced to a single list_head. The external dfops mechanism is unused and thus everywhere a (permanent) transaction is accessible the associated dfops structure is as well. Remove the xfs_defer_ops structure and fold the list_head into the transaction. Also remove the last remnant of external dfops in xfs_trans_dup(). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: pass transaction to xfs_defer_add()Brian Foster
The majority of remaining references to struct xfs_defer_ops in XFS are associated with xfs_defer_add(). At this point, there are no more external xfs_defer_ops users left. All instances of xfs_defer_ops are embedded in the transaction, which means we can safely pass the transaction down to the dfops add interface. Update xfs_defer_add() to receive the transaction as a parameter. Various subsystems implement wrappers to allocate and construct the context specific data structures for the associated deferred operation type. Update these to also carry the transaction down as needed and clean up unused dfops parameters along the way. This removes most of the remaining references to struct xfs_defer_ops throughout the code and facilitates removal of the structure. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> [darrick: fix unused variable warnings with ftrace disabled] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: replace xfs_defer_ops ->dop_pending with on-stack listBrian Foster
The xfs_defer_ops ->dop_pending list is used to track active deferred operations once intents are logged. These items must be aborted in the event of an error. The list is populated as intents are logged and items are removed as they complete (or are aborted). Now that xfs_defer_finish() cancels on error, there is no need to ever access ->dop_pending outside of xfs_defer_finish(). The list is only ever populated after xfs_defer_finish() begins and is either completed or cancelled before it returns. Remove ->dop_pending from xfs_defer_ops and replace it with a local list in the xfs_defer_finish() path. Pass the local list to the various helpers now that it is not accessible via dfops. Note that we have to check for NULL in the abort case as the final tx roll occurs outside of the scope of the new local list (once the dfops has completed and thus drained the list). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: clean out superfluous dfops dop params/varsBrian Foster
The dfops code still passes around the xfs_defer_ops pointer superfluously in a few places. Clean this up wherever the transaction will suffice. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: drop dop param from xfs_defer_op_type ->finish_item() callbackBrian Foster
The dfops infrastructure ->finish_item() callback passes the transaction and dfops as separate parameters. Since dfops is always part of a transaction, the latter parameter is no longer necessary. Remove it from the various callbacks. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: automatic dfops inode reloggingBrian Foster
Inodes that are held across deferred operations are explicitly joined to the dfops structure to ensure appropriate relogging. While inodes are currently joined explicitly, we can detect the conditions that require relogging at dfops finish time by inspecting the transaction item list for inodes with ili_lock_flags == 0. Replace the xfs_defer_ijoin() infrastructure with such detection and automatic relogging of held inodes. This eliminates the need for the per-dfops inode list, replaced by an on-stack variant in xfs_defer_trans_roll(). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: automatic dfops buffer reloggingBrian Foster
Buffers that are held across deferred operations are explicitly joined to the dfops structure to ensure appropriate relogging. While buffers are currently joined explicitly, we can detect the conditions that require relogging at dfops finish time by inspecting the transaction item list for held buffers. Replace the xfs_defer_bjoin() infrastructure with such detection and automatic relogging of held buffers. This eliminates the need for the per-dfops buffer list, replaced by an on-stack variant in xfs_defer_trans_roll(). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: replace dop_low with transaction flagBrian Foster
The dop_low field enables the low free space allocation mode when a previous allocation has detected difficulty allocating blocks. It has historically been part of the xfs_defer_ops structure, which means if enabled, it remains enabled across a set of transactions until the deferred operations have completed and the dfops is reset. Now that the dfops is embedded in the transaction, we can save a bit more space by using a transaction flag rather than a standalone boolean. Drop the ->dop_low field and replace it with a transaction flag that is set at the same points, carried across rolling transactions and cleared on completion of deferred operations. This essentially emulates the behavior of ->dop_low and so should not change behavior. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: pass transaction to dfops reset/move helpersBrian Foster
All callers pass ->t_dfops of the associated transactions. Refactor the helpers to receive the transactions and facilitate further cleanups between xfs_defer_ops and xfs_trans. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-02xfs: remove unused __xfs_defer_cancel() internal helperBrian Foster
With no more external dfops users, there is no need for an xfs_defer_ops cancel wrapper. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-26xfs: bypass final dfops roll in trans commit pathBrian Foster
Once xfs_defer_finish() has completed all deferred operations, it checks the dirty state of the transaction and rolls it once more to return a clean transaction for the caller. This primarily to cover the case where repeated xfs_defer_finish() calls are made in a loop and we need to make sure that the caller starts the next iteration with a clean transaction. Otherwise we risk transaction reservation overrun. This final transaction roll is not required in the transaction commit path, however, because the transaction is immediately committed and freed after dfops completion. Refactor the final roll into a separate helper such that we can avoid it in the transaction commit path. Lift the dfops reset as well so dfops remains valid until after the last call to xfs_defer_trans_roll(). The reset is also unnecessary in the transaction commit path because the transaction is about to complete. This eliminates unnecessary regrants of transactions where the associated transaction roll can be replaced by a transaction commit. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Bill O'Donnell <billodo@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-26xfs: drop unnecessary xfs_defer_finish() dfops parameterBrian Foster
Every caller of xfs_defer_finish() now passes the transaction and its associated ->t_dfops. The xfs_defer_ops parameter is therefore no longer necessary and can be removed. Since most xfs_defer_finish() callers also have to consider xfs_defer_cancel() on error, update the latter to also receive the transaction for consistency. The log recovery code contains an outlier case that cancels a dfops directly without an available transaction. Retain an internal wrapper to support this outlier case for the time being. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Bill O'Donnell <billodo@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-26xfs: support embedded dfops in transactionBrian Foster
The dfops structure used by multi-transaction operations is typically stored on the stack and carried around by the associated transaction. The lifecycle of dfops does not quite match that of the transaction, but they are tightly related in that the former depends on the latter. The relationship of these objects is tight enough that we can avoid the cumbersome boilerplate code required in most cases to manage them separately by just embedding an xfs_defer_ops in the transaction itself. This means that a transaction allocation returns with an initialized dfops, a transaction commit finishes pending deferred items before the tx commit, a transaction cancel cancels the dfops before the transaction and a transaction dup operation transfers the current dfops state to the new transaction. The dup operation is slightly complicated by the fact that we can no longer just copy a dfops pointer from the old transaction to the new transaction. This is solved through a dfops move helper that transfers the pending items and other dfops state across the transactions. This also requires that transaction rolling code always refer to the transaction for the current dfops reference. Finally, to facilitate incremental conversion to the internal dfops and continue to support the current external dfops mode of operation, create the new ->t_dfops_internal field with a layer of indirection. On allocation, ->t_dfops points to the internal dfops. This state is overridden by callers who re-init a local dfops on the transaction. Once ->t_dfops is overridden, the external dfops reference is maintained as the transaction rolls. This patch adds the fundamental ability to support an internal dfops. All codepaths that perform deferred processing continue to override the internal dfops until they are converted over in subsequent patches. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Bill O'Donnell <billodo@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-26xfs: pack holes in xfs_defer_ops and xfs_transBrian Foster
Both structures have holes due to member alignment. Move dop_low to the end of xfs_defer ops to sanitize the cache line alignment and move t_flags to save 8 bytes in xfs_trans. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bill O'Donnell <billodo@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-26xfs: remove unused deferred ops committed fieldBrian Foster
dop_committed is set when deferred item processing rolls the transaction at least once, but is only ever accessed in tracepoints. The transaction roll/commit events are already available via independent tracepoints, so remove the otherwise unused field. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bill O'Donnell <billodo@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-11xfs: remove xfs_defer_init() firstblock paramBrian Foster
All but one caller of xfs_defer_init() passes in the ->t_firstblock of the associated transaction. The one outlier is xlog_recover_process_intents(), which simply passes a dummy value because a valid pointer is required. This firstblock variable can simply be removed. At this point we could remove the xfs_defer_init() firstblock parameter and initialize ->t_firstblock directly. Even that is not necessary, however, because ->t_firstblock is automatically reinitialized in the new transaction on a transaction roll. Since xfs_defer_init() should never occur more than once on a particular transaction (since the corresponding finish will roll it), replace the reinit from xfs_defer_init() with an assert that verifies the transaction has a NULLFSBLOCK firstblock. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-11xfs: refactor dfops init to attach to transactionBrian Foster
Most callers of xfs_defer_init() immediately attach the dfops structure to a transaction. Add a transaction parameter to eliminate much of this boilerplate code. This also helps self-document the fact that many codepaths now expect a dfops pointer implicitly via xfs_trans->t_dfops. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-06-06xfs: convert to SPDX license tagsDave Chinner
Remove the verbose license text from XFS files and replace them with SPDX tags. This does not change the license of any of the code, merely refers to the common, up-to-date license files in LICENSES/ This change was mostly scripted. fs/xfs/Makefile and fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected and modified by the following command: for f in `git grep -l "GNU General" fs/xfs/` ; do echo $f cat $f | awk -f hdr.awk > $f.new mv -f $f.new $f done And the hdr.awk script that did the modification (including detecting the difference between GPL-2.0 and GPL-2.0+ licenses) is as follows: $ cat hdr.awk BEGIN { hdr = 1.0 tag = "GPL-2.0" str = "" } /^ \* This program is free software/ { hdr = 2.0; next } /any later version./ { tag = "GPL-2.0+" next } /^ \*\// { if (hdr > 0.0) { print "// SPDX-License-Identifier: " tag print str print $0 str="" hdr = 0.0 next } print $0 next } /^ \* / { if (hdr > 1.0) next if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 next } /^ \*/ { if (hdr > 0.0) next print $0 next } // { if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 } END { } $ Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-09xfs: defer agfl block frees when dfops is availableBrian Foster
The AGFL fixup code executes before every block allocation/free and rectifies the AGFL based on the current, dynamic allocation requirements of the fs. The AGFL must hold a minimum number of blocks to satisfy a worst case split of the free space btrees caused by the impending allocation operation. The AGFL is also updated to maintain the implicit requirement for a minimum number of free slots to satisfy a worst case join of the free space btrees. Since the AGFL caches individual blocks, AGFL reduction typically involves multiple, single block frees. We've had reports of transaction overrun problems during certain workloads that boil down to AGFL reduction freeing multiple blocks and consuming more space in the log than was reserved for the transaction. Since the objective of freeing AGFL blocks is to ensure free AGFL free slots are available for the upcoming allocation, one way to address this problem is to release surplus blocks from the AGFL immediately but defer the free of those blocks (similar to how file-mapped blocks are unmapped from the file in one transaction and freed via a deferred operation) until the transaction is rolled. This turns AGFL reduction into an operation with predictable log reservation consumption. Add the capability to defer AGFL block frees when a deferred ops list is available to the AGFL fixup code. Add a dfops pointer to the transaction to carry dfops through various contexts to the allocator context. Deferring AGFL frees is conditional behavior based on whether the transaction pointer is populated. The long term objective is to reuse the transaction pointer to clean up all unrelated callchains that pass dfops on the stack along with a transaction and in doing so, consistently defer AGFL blocks from the allocator. A bit of customization is required to handle deferred completion processing because AGFL blocks are accounted against a per-ag reservation pool and AGFL blocks are not inserted into the extent busy list when freed (they are inserted when used and released back to the AGFL). Reuse the majority of the existing deferred extent free infrastructure and customize it appropriately to handle AGFL blocks. Note that this patch only adds infrastructure. It does not change behavior because no callers have been updated to pass ->t_agfl_dfops into the allocation code. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-12-14xfs: add the ability to join a held buffer to a defer_opsDarrick J. Wong
In certain cases, defer_ops callers will lock a buffer and want to hold the lock across transaction rolls. Similar to ijoined inodes, we want to dirty & join the buffer with each transaction roll in defer_finish so that afterwards the caller still owns the buffer lock and we haven't inadvertently pinned the log. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-09-01xfs: remove the ip argument to xfs_defer_finishChristoph Hellwig
And instead require callers to explicitly join the inode using xfs_defer_ijoin. Also consolidate the defer error handling in a few places using a goto label. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-09-01xfs: rename xfs_defer_join to xfs_defer_ijoinChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-10-04xfs: implement deferred bmbt map/unmap operationsDarrick J. Wong
Implement deferred versions of the inode block map/unmap functions. These will be used in subsequent patches to make reflink operations atomic. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-03xfs: connect refcount adjust functions to upper layersDarrick J. Wong
Plumb in the upper level interface to schedule and finish deferred refcount operations via the deferred ops mechanism. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-08-30xfs: track log done items directly in the deferred pending work itemDarrick J. Wong
Christoph reports slab corruption when a deferred refcount update aborts during _defer_finish(). The cause of this was broken log item state tracking in xfs_defer_pending -- upon an abort, _defer_trans_abort() will call abort_intent on all intent items, including the ones that have already had a done item attached. This is incorrect because each intent item has 2 refcount: the first is released when the intent item is committed to the log; and the second is released when the _done_ item is committed to the log, or by the intent creator if there is no done item. In other words, once we log the done item, responsibility for releasing the intent item's second refcount is transferred to the done item and /must not/ be performed by anything else. The dfp_committed flag should have been tracking whether or not we had a done item so that _defer_trans_abort could decide if it needs to abort the intent item, but due to a thinko this was not the case. Rip it out and track the done item directly so that we do the right thing w.r.t. intent item freeing. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-08-03xfs: enable the xfs_defer mechanism to process rmaps to updateDarrick J. Wong
Connect the xfs_defer mechanism with the pieces that we'll need to handle deferred rmap updates. We'll wire up the existing code to our new deferred mechanism later. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-08-03xfs: change xfs_bmap_{finish,cancel,init,free} -> xfs_defer_*Darrick J. Wong
Drop the compatibility shims that we were using to integrate the new deferred operation mechanism into the existing code. No new code. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-08-03xfs: rework xfs_bmap_free callers to use xfs_defer_opsDarrick J. Wong
Restructure everything that used xfs_bmap_free to use xfs_defer_ops instead. For now we'll just remove the old symbols and play some cpp magic to make it work; in the next patch we'll actually rename everything. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-08-03xfs: enable the xfs_defer mechanism to process extents to freeDarrick J. Wong
Connect the xfs_defer mechanism with the pieces that we'll need to handle deferred extent freeing. We'll wire up the existing code to our new deferred mechanism later. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-08-03xfs: move deferred operations into a separate fileDarrick J. Wong
All the code around struct xfs_bmap_free basically implements a deferred operation framework through which we can roll transactions (to unlock buffers and avoid violating lock order rules) while managing all the necessary log redo items. Previously we only used this code to free extents after some sort of mapping operation, but with the advent of rmap and reflink, we suddenly need to do more than that. With that in mind, xfs_bmap_free really becomes a deferred ops control structure. Rename the structure and move the deferred ops into their own file to avoid further bloating of the bmap code. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>