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path: root/fs/xfs/xfs_alloc.c
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2012-11-16xfs: convert buffer verifiers to an ops structure.Dave Chinner
To separate the verifiers from iodone functions and associate read and write verifiers at the same time, introduce a buffer verifier operations structure to the xfs_buf. This avoids the need for assigning the write verifier, clearing the iodone function and re-running ioend processing in the read verifier, and gets rid of the nasty "b_pre_io" name for the write verifier function pointer. If we ever need to, it will also be easier to add further content specific callbacks to a buffer with an ops structure in place. We also avoid needing to export verifier functions, instead we can simply export the ops structures for those that are needed outside the function they are defined in. This patch also fixes a directory block readahead verifier issue it exposed. This patch also adds ops callbacks to the inode/alloc btree blocks initialised by growfs. These will need more work before they will work with CRCs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: connect up write verifiers to new buffersDave Chinner
Metadata buffers that are read from disk have write verifiers already attached to them, but newly allocated buffers do not. Add appropriate write verifiers to all new metadata buffers. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: add pre-write metadata buffer verifier callbacksDave Chinner
These verifiers are essentially the same code as the read verifiers, but do not require ioend processing. Hence factor the read verifier functions and add a new write verifier wrapper that is used as the callback. This is done as one large patch for all verifiers rather than one patch per verifier as the change is largely mechanical. This includes hooking up the write verifier via the read verifier function. Hooking up the write verifier for buffers obtained via xfs_trans_get_buf() will be done in a separate patch as that touches code in many different places rather than just the verifier functions. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: verify AGFL blocks as they are read from diskDave Chinner
Add an AGFL block verify callback function and pass it into the buffer read functions. While this commit adds verification code to the AGFL, it cannot be used reliably until the CRC format change comes along as mkfs does not initialise the full AGFL. Hence it can be full of garbage at the first mount and will fail verification right now. CRC enabled filesystems won't have this problem, so leave the code that has already been written ifdef'd out until the proper time. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: verify AGF blocks as they are read from diskDave Chinner
Add an AGF block verify callback function and pass it into the buffer read functions. This replaces the existing verification that is done after the read completes. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: make buffer read verication an IO completion functionDave Chinner
Add a verifier function callback capability to the buffer read interfaces. This will be used by the callers to supply a function that verifies the contents of the buffer when it is read from disk. This patch does not provide callback functions, but simply modifies the interfaces to allow them to be called. The reason for adding this to the read interfaces is that it is very difficult to tell fom the outside is a buffer was just read from disk or whether we just pulled it out of cache. Supplying a callbck allows the buffer cache to use it's internal knowledge of the buffer to execute it only when the buffer is read from disk. It is intended that the verifier functions will mark the buffer with an EFSCORRUPTED error when verification fails. This allows the reading context to distinguish a verification error from an IO error, and potentially take further actions on the buffer (e.g. attempt repair) based on the error reported. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-10-18xfs: move allocation stack switch up to xfs_bmapi_allocateDave Chinner
Switching stacks are xfs_alloc_vextent can cause deadlocks when we run out of worker threads on the allocation workqueue. This can occur because xfs_bmap_btalloc can make multiple calls to xfs_alloc_vextent() and even if xfs_alloc_vextent() fails it can return with the AGF locked in the current allocation transaction. If we then need to make another allocation, and all the allocation worker contexts are exhausted because the are blocked waiting for the AGF lock, holder of the AGF cannot get it's xfs-alloc_vextent work completed to release the AGF. Hence allocation effectively deadlocks. To avoid this, move the stack switch one layer up to xfs_bmapi_allocate() so that all of the allocation attempts in a single switched stack transaction occur in a single worker context. This avoids the problem of an allocation being blocked waiting for a worker thread whilst holding the AGF. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-10-18xfs: introduce XFS_BMAPI_STACK_SWITCHDave Chinner
Certain allocation paths through xfs_bmapi_write() are in situations where we have limited stack available. These are almost always in the buffered IO writeback path when convertion delayed allocation extents to real extents. The current stack switch occurs for userdata allocations, which means we also do stack switches for preallocation, direct IO and unwritten extent conversion, even those these call chains have never been implicated in a stack overrun. Hence, let's target just the single stack overun offended for stack switches. To do that, introduce a XFS_BMAPI_STACK_SWITCH flag that the caller can pass xfs_bmapi_write() to indicate it should switch stacks if it needs to do allocation. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-10-18xfs: zero allocation_args on the kernel stackMark Tinguely
Zero the kernel stack space that makes up the xfs_alloc_arg structures. Signed-off-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-13xfs: don't defer metadata allocation to the workqueueDave Chinner
Almost all metadata allocations come from shallow stack usage situations. Avoid the overhead of switching the allocation to a workqueue as we are not in danger of running out of stack when making these allocations. Metadata allocations are already marked through the args that are passed down, so this is trivial to do. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reported-by: Mel Gorman <mgorman@suse.de> Tested-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-13xfs: really fix the cursor leak in xfs_alloc_ag_vextent_nearDave Chinner
The current cursor is reallocated when retrying the allocation, so the existing cursor needs to be destroyed in both the restart and the failure cases. Signed-off-by: Dave Chinner <dchinner@redhat.com> Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-06-21xfs: fix allocbt cursor leak in xfs_alloc_ag_vextent_nearDave Chinner
When we fail to find an matching extent near the requested extent specification during a left-right distance search in xfs_alloc_ag_vextent_near, we fail to free the original cursor that we used to look up the XFS_BTNUM_CNT tree and hence leak it. Reported-by: Chris J Arges <chris.j.arges@canonical.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-06-20xfs: fix debug_object WARN at xfs_alloc_vextent()Jeff Liu
Fengguang reports: [ 780.529603] XFS (vdd): Ending clean mount [ 781.454590] ODEBUG: object is on stack, but not annotated [ 781.455433] ------------[ cut here ]------------ [ 781.455433] WARNING: at /c/kernel-tests/sound/lib/debugobjects.c:301 __debug_object_init+0x173/0x1f1() [ 781.455433] Hardware name: Bochs [ 781.455433] Modules linked in: [ 781.455433] Pid: 26910, comm: kworker/0:2 Not tainted 3.4.0+ #51 [ 781.455433] Call Trace: [ 781.455433] [<ffffffff8106bc84>] warn_slowpath_common+0x83/0x9b [ 781.455433] [<ffffffff8106bcb6>] warn_slowpath_null+0x1a/0x1c [ 781.455433] [<ffffffff814919a5>] __debug_object_init+0x173/0x1f1 [ 781.455433] [<ffffffff81491c65>] debug_object_init+0x14/0x16 [ 781.455433] [<ffffffff8108842a>] __init_work+0x20/0x22 [ 781.455433] [<ffffffff8134ea56>] xfs_alloc_vextent+0x6c/0xd5 Use INIT_WORK_ONSTACK in xfs_alloc_vextent instead of INIT_WORK. Reported-by: Wu Fengguang <wfg@linux.intel.com> Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14xfs: make xfs_extent_busy_trim not staticBen Myers
Commit e459df5, 'xfs: move busy extent handling to it's own file' moved some code from xfs_alloc.c into xfs_extent_busy.c for convenience in userspace code merges. One of the functions moved is xfs_extent_busy_trim (formerly xfs_alloc_busy_trim) which is defined STATIC. Unfortunately this function is still used in xfs_alloc.c, and this results in an undefined symbol in xfs.ko. Make xfs_extent_busy_trim not static and add its prototype to xfs_extent_busy.h. Signed-off-by: Ben Myers <bpm@sgi.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com>
2012-05-14xfs: clean up busy extent namingDave Chinner
Now that the busy extent tracking has been moved out of the allocation files, clean up the namespace it uses to "xfs_extent_busy" rather than a mix of "xfs_busy" and "xfs_alloc_busy". Signed-off-by: Dave Chinner<dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14xfs: move busy extent handling to it's own fileDave Chinner
To make it easier to handle userspace code merges, move all the busy extent handling out of the allocation code and into it's own file. The userspace code does not need the busy extent code, so this simplifies the merging of the kernel code into the userspace xfsprogs library. Because the busy extent code has been almost completely rewritten over the past couple of years, also update the copyright on this new file to include the authors that made all those changes. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14xfs: move xfsagino_t to xfs_types.hDave Chinner
Untangle the header file includes a bit by moving the definition of xfs_agino_t to xfs_types.h. This removes the dependency that xfs_ag.h has on xfs_inum.h, meaning we don't need to include xfs_inum.h everywhere we include xfs_ag.h. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-03-27xfs: fix fstrim offset calculationsDave Chinner
xfs_ioc_fstrim() doesn't treat the incoming offset and length correctly. It treats them as a filesystem block address, rather than a disk address. This is wrong because the range passed in is a linear representation, while the filesystem block address notation is a sparse representation. Hence we cannot convert the range direct to filesystem block units and then use that for calculating the range to trim. While this sounds dangerous, the problem is limited to calculating what AGs need to be trimmed. The code that calcuates the actual ranges to trim gets the right result (i.e. only ever discards free space), even though it uses the wrong ranges to limit what is trimmed. Hence this is not a bug that endangers user data. Fix this by treating the range as a disk address range and use the appropriate functions to convert the range into the desired formats for calculations. Further, fix the first free extent lookup (the longest) to actually find the largest free extent. Currently this lookup uses a <= lookup, which results in finding the extent to the left of the largest because we can never get an exact match on the largest extent. This is due to the fact that while we know it's size, we don't know it's location and so the exact match fails and we move one record to the left to get the next largest extent. Instead, use a >= search so that the lookup returns the largest extent regardless of the fact we don't get an exact match on it. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-03-22xfs: introduce an allocation workqueueDave Chinner
We currently have significant issues with the amount of stack that allocation in XFS uses, especially in the writeback path. We can easily consume 4k of stack between mapping the page, manipulating the bmap btree and allocating blocks from the free list. Not to mention btree block readahead and other functionality that issues IO in the allocation path. As a result, we can no longer fit allocation in the writeback path in the stack space provided on x86_64. To alleviate this problem, introduce an allocation workqueue and move all allocations to a seperate context. This can be easily added as an interposing layer into xfs_alloc_vextent(), which takes a single argument structure and does not return until the allocation is complete or has failed. To do this, add a work structure and a completion to the allocation args structure. This allows xfs_alloc_vextent to queue the args onto the workqueue and wait for it to be completed by the worker. This can be done completely transparently to the caller. The worker function needs to ensure that it sets and clears the PF_TRANS flag appropriately as it is being run in an active transaction context. Work can also be queued in a memory reclaim context, so a rescuer is needed for the workqueue. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2011-10-12xfs: remove XFS_BUF_SET_VTYPE and XFS_BUF_SET_VTYPE_REFChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-25xfs: Remove the macro XFS_BUF_ERROR and familyChandra Seetharaman
Remove the definitions and usage of the macros XFS_BUF_ERROR, XFS_BUF_GETERROR and XFS_BUF_ISERROR. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-08xfs: remove variables that serve no purpose in xfs_alloc_ag_vextent_exact()Chandra Seetharaman
Remove two variables that serve no purpose in xfs_alloc_ag_vextent_exact(). Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-07-08xfs: byteswap constants instead of variablesChristoph Hellwig
Micro-optimize various comparisms by always byteswapping the constant instead of the variable, which allows to do the swap at compile instead of runtime. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Alex Elder <aelder@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2011-05-24xfs: do not discard alloc btree blocksChristoph Hellwig
Blocks for the allocation btree are allocated from and released to the AGFL, and thus frequently reused. Even worse we do not have an easy way to avoid using an AGFL block when it is discarded due to the simple FILO list of free blocks, and thus can frequently stall on blocks that are currently undergoing a discard. Add a flag to the busy extent tracking structure to skip the discard for allocation btree blocks. In normal operation these blocks are reused frequently enough that there is no need to discard them anyway, but if they spill over to the allocation btree as part of a balance we "leak" blocks that we would otherwise discard. We could fix this by adding another flag and keeping these block in the rbtree even after they aren't busy any more so that we could discard them when they migrate out of the AGFL. Given that this would cause significant overhead I don't think it's worthwile for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-05-24xfs: add online discard supportChristoph Hellwig
Now that we have reliably tracking of deleted extents in a transaction we can easily implement "online" discard support which calls blkdev_issue_discard once a transaction commits. The actual discard is a two stage operation as we first have to mark the busy extent as not available for reuse before we can start the actual discard. Note that we don't bother supporting discard for the non-delaylog mode. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-05-19xfs: obey minleft values during extent allocation correctlyDave Chinner
When allocating an extent that is long enough to consume the remaining free space in an AG, we need to ensure that the allocation leaves enough space in the AG for any subsequent bmap btree blocks that are needed to track the new extent. These have to be allocated in the same AG as we only reserve enough blocks in an allocation transaction for modification of the freespace trees in a single AG. xfs_alloc_fix_minleft() has been considering blocks on the AGFL as free blocks available for extent and bmbt block allocation, which is not correct - blocks on the AGFL are there exclusively for the use of the free space btrees. As a result, when minleft is less than the number of blocks on the AGFL, xfs_alloc_fix_minleft() does not trim the given extent to leave minleft blocks available for bmbt allocation, and hence we can fail allocation during bmbt record insertion. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-04-28xfs: reduce the number of pagb_lock roundtrips in xfs_alloc_clear_busyChristoph Hellwig
Instead of finding the per-ag and then taking and releasing the pagb_lock for every single busy extent completed sort the list of busy extents and only switch betweens AGs where nessecary. This becomes especially important with the online discard support which will hit this lock more often. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-04-28xfs: exact busy extent trackingChristoph Hellwig
Update the extent tree in case we have to reuse a busy extent, so that it always is kept uptodate. This is done by replacing the busy list searches with a new xfs_alloc_busy_reuse helper, which updates the busy extent tree in case of a reuse. This allows us to allow reusing metadata extents unconditionally, and thus avoid log forces especially for allocation btree blocks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-04-28xfs: do not immediately reuse busy extent rangesChristoph Hellwig
Every time we reallocate a busy extent, we cause a synchronous log force to occur to ensure the freeing transaction is on disk before we continue and use the newly allocated extent. This is extremely sub-optimal as we have to mark every transaction with blocks that get reused as synchronous. Instead of searching the busy extent list after deciding on the extent to allocate, check each candidate extent during the allocation decisions as to whether they are in the busy list. If they are in the busy list, we trim the busy range out of the extent we have found and determine if that trimmed range is still OK for allocation. In many cases, this check can be incorporated into the allocation extent alignment code which already does trimming of the found extent before determining if it is a valid candidate for allocation. Based on earlier patches from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-04-28xfs: optimize AGFL refillsChristoph Hellwig
While we need to make sure we do not reuse busy extents, there is no need to force out busy extents when moving them between the AGFL and the freespace btree as we still take care of that when doing the real allocation. To avoid the log force when just moving extents from the different free space tracking structures, move the busy search out of xfs_alloc_get_freelist into the callers that need it, and move the busy list insert from xfs_free_ag_extent which is used both by AGFL refills and real allocation to xfs_free_extent, which is only used by the latter. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-04-08xfs: catch bad block numbers freeing extents.Dave Chinner
A fuzzed filesystem crashed a kernel when freeing an extent with a block number beyond the end of the filesystem. Convert all the debug asserts in xfs_free_extent() to active checks so that we catch bad extents and return that the filesytsem is corrupted rather than crashing. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Alex Elder <aelder@sgi.com>
2011-03-09xfs: factor agf counter updates into a helperChristoph Hellwig
Updating the AGF and transactions counters is duplicated between allocating and freeing extents. Factor the code into a common helper. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-03-09xfs: clean up the xfs_alloc_compute_aligned calling conventionChristoph Hellwig
Pass a xfs_alloc_arg structure to xfs_alloc_compute_aligned and derive the alignment and minlen paramters from it. This cleans up the existing callers, and we'll need even more information from the xfs_alloc_arg in subsequent patches. Based on a patch from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2011-01-12xfs: add FITRIM supportChristoph Hellwig
Allow manual discards from userspace using the FITRIM ioctl. This is not intended to be run during normal workloads, as the freepsace btree walks can cause large performance degradation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-12-16xfs: factor duplicate code in xfs_alloc_ag_vextent_near into a helperChristoph Hellwig
Add a new xfs_alloc_find_best_extent that does a forward/backward search in the allocation btree. That code previously was existed two times in xfs_alloc_ag_vextent_near, once for each search direction. Based on an earlier patch from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-12-16xfs: clean up xfs_alloc_ag_vextent_exactChristoph Hellwig
Use a goto label to consolidate all block not found cases, and add a tracepoint for them. Also clean up a few whitespace issues. Based on an earlier patch from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-10-18xfs: eliminate some newly-reported gcc warningsPoyo VL
Ionut Gabriel Popescu <poyo_vl@yahoo.com> submitted a simple change to eliminate some "may be used uninitialized" warnings when building XFS. The reported condition seems to be something that GCC did not used to recognize or report. The warnings were produced by: gcc version 4.5.0 20100604 [gcc-4_5-branch revision 160292] (SUSE Linux) Signed-off-by: Ionut Gabriel Popescu <poyo_vl@yahoo.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26xfs: fix gcc 4.6 set but not read and unused statement warningsChristoph Hellwig
[hch: dropped a few hunks that need structural changes instead] Signed-off-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26xfs: remove unneeded #include statementsChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
2010-07-26xfs: drop dmapi hooksChristoph Hellwig
Dmapi support was never merged upstream, but we still have a lot of hooks bloating XFS for it, all over the fast pathes of the filesystem. This patch drops over 700 lines of dmapi overhead. If we'll ever get HSM support in mainline at least the namespace events can be done much saner in the VFS instead of the individual filesystem, so it's not like this is much help for future work. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-05-24xfs: Improve scalability of busy extent trackingDave Chinner
When we free a metadata extent, we record it in the per-AG busy extent array so that it is not re-used before the freeing transaction hits the disk. This array is fixed size, so when it overflows we make further allocation transactions synchronous because we cannot track more freed extents until those transactions hit the disk and are completed. Under heavy mixed allocation and freeing workloads with large log buffers, we can overflow this array quite easily. Further, the array is sparsely populated, which means that inserts need to search for a free slot, and array searches often have to search many more slots that are actually used to check all the busy extents. Quite inefficient, really. To enable this aspect of extent freeing to scale better, we need a structure that can grow dynamically. While in other areas of XFS we have used radix trees, the extents being freed are at random locations on disk so are better suited to being indexed by an rbtree. So, use a per-AG rbtree indexed by block number to track busy extents. This incures a memory allocation when marking an extent busy, but should not occur too often in low memory situations. This should scale to an arbitrary number of extents so should not be a limitation for features such as in-memory aggregation of transactions. However, there are still situations where we can't avoid allocating busy extents (such as allocation from the AGFL). To minimise the overhead of such occurences, we need to avoid doing a synchronous log force while holding the AGF locked to ensure that the previous transactions are safely on disk before we use the extent. We can do this by marking the transaction doing the allocation as synchronous rather issuing a log force. Because of the locking involved and the ordering of transactions, the synchronous transaction provides the same guarantees as a synchronous log force because it ensures that all the prior transactions are already on disk when the synchronous transaction hits the disk. i.e. it preserves the free->allocate order of the extent correctly in recovery. By doing this, we avoid holding the AGF locked while log writes are in progress, hence reducing the length of time the lock is held and therefore we increase the rate at which we can allocate and free from the allocation group, thereby increasing overall throughput. The only problem with this approach is that when a metadata buffer is marked stale (e.g. a directory block is removed), then buffer remains pinned and locked until the log goes to disk. The issue here is that if that stale buffer is reallocated in a subsequent transaction, the attempt to lock that buffer in the transaction will hang waiting the log to go to disk to unlock and unpin the buffer. Hence if someone tries to lock a pinned, stale, locked buffer we need to push on the log to get it unlocked ASAP. Effectively we are trading off a guaranteed log force for a much less common trigger for log force to occur. Ideally we should not reallocate busy extents. That is a much more complex fix to the problem as it involves direct intervention in the allocation btree searches in many places. This is left to a future set of modifications. Finally, now that we track busy extents in allocated memory, we don't need the descriptors in the transaction structure to point to them. We can replace the complex busy chunk infrastructure with a simple linked list of busy extents. This allows us to remove a large chunk of code, making the overall change a net reduction in code size. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21xfs: cleanup up xfs_log_force calling conventionsChristoph Hellwig
Remove the XFS_LOG_FORCE argument which was always set, and the XFS_LOG_URGE define, which was never used. Split xfs_log_force into a two helpers - xfs_log_force which forces the whole log, and xfs_log_force_lsn which forces up to the specified LSN. The underlying implementations already were entirely separate, as were the users. Also re-indent the new _xfs_log_force/_xfs_log_force which previously had a weird coding style. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21xfs: remove duplicate buffer flagsChristoph Hellwig
Currently we define aliases for the buffer flags in various namespaces, which only adds confusion. Remove all but the XBF_ flags to clean this up a bit. Note that we still abuse XFS_B_ASYNC/XBF_ASYNC for some non-buffer uses, but I'll clean that up later. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-15xfs: embed the pagb_list array in the perag structureDave Chinner
Now that the perag structure is allocated memory rather than held in an array, we don't need to have the busy extent array external to the structure. Embed it into the perag structure to avoid needing an extra allocation when setting up. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-15xfs: Replace per-ag array with a radix treeDave Chinner
The use of an array for the per-ag structures requires reallocation of the array when growing the filesystem. This requires locking access to the array to avoid use after free situations, and the locking is difficult to get right. To avoid needing to reallocate an array, change the per-ag structures to an allocated object per ag and index them using a tree structure. The AGs are always densely indexed (hence the use of an array), but the number supported is 2^32 and lookups tend to be random and hence indexing needs to scale. A simple choice is a radix tree - it works well with this sort of index. This change also removes another large contiguous allocation from the mount/growfs path in XFS. The growing process now needs to change to only initialise the new AGs required for the extra space, and as such only needs to exclusively lock the tree for inserts. The rest of the code only needs to lock the tree while doing lookups, and hence this will remove all the deadlocks that currently occur on the m_perag_lock as it is now an innermost lock. The lock is also changed to a spinlock from a read/write lock as the hold time is now extremely short. To complete the picture, the per-ag structures will need to be reference counted to ensure that we don't free/modify them while they are still in use. This will be done in subsequent patch. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-15xfs: Don't directly reference m_perag in allocation codeDave Chinner
Start abstracting the perag references so that the indexing of the structures is not directly coded into all the places that uses the perag structures. This will allow us to separate the use of the perag structure and the way it is indexed and hence avoid the known deadlocks related to growing a busy filesystem. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-10xfs: Ensure we force all busy extents in range to diskDave Chinner
When we search for and find a busy extent during allocation we force the log out to ensure the extent free transaction is on disk before the allocation transaction. The current implementation has a subtle bug in it--it does not handle multiple overlapping ranges. That is, if we free lots of little extents into a single contiguous extent, then allocate the contiguous extent, the busy search code stops searching at the first extent it finds that overlaps the allocated range. It then uses the commit LSN of the transaction to force the log out to. Unfortunately, the other busy ranges might have more recent commit LSNs than the first busy extent that is found, and this results in xfs_alloc_search_busy() returning before all the extent free transactions are on disk for the range being allocated. This can lead to potential metadata corruption or stale data exposure after a crash because log replay won't replay all the extent free transactions that cover the allocation range. Modified-by: Alex Elder <aelder@sgi.com> (Dropped the "found" argument from the xfs_alloc_busysearch trace event.) Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-12-15xfs: event tracing supportChristoph Hellwig
Convert the old xfs tracing support that could only be used with the out of tree kdb and xfsidbg patches to use the generic event tracer. To use it make sure CONFIG_EVENT_TRACING is enabled and then enable all xfs trace channels by: echo 1 > /sys/kernel/debug/tracing/events/xfs/enable or alternatively enable single events by just doing the same in one event subdirectory, e.g. echo 1 > /sys/kernel/debug/tracing/events/xfs/xfs_ihold/enable or set more complex filters, etc. In Documentation/trace/events.txt all this is desctribed in more detail. To reads the events do a cat /sys/kernel/debug/tracing/trace Compared to the last posting this patch converts the tracing mostly to the one tracepoint per callsite model that other users of the new tracing facility also employ. This allows a very fine-grained control of the tracing, a cleaner output of the traces and also enables the perf tool to use each tracepoint as a virtual performance counter, allowing us to e.g. count how often certain workloads git various spots in XFS. Take a look at http://lwn.net/Articles/346470/ for some examples. Also the btree tracing isn't included at all yet, as it will require additional core tracing features not in mainline yet, I plan to deliver it later. And the really nice thing about this patch is that it actually removes many lines of code while adding this nice functionality: fs/xfs/Makefile | 8 fs/xfs/linux-2.6/xfs_acl.c | 1 fs/xfs/linux-2.6/xfs_aops.c | 52 - fs/xfs/linux-2.6/xfs_aops.h | 2 fs/xfs/linux-2.6/xfs_buf.c | 117 +-- fs/xfs/linux-2.6/xfs_buf.h | 33 fs/xfs/linux-2.6/xfs_fs_subr.c | 3 fs/xfs/linux-2.6/xfs_ioctl.c | 1 fs/xfs/linux-2.6/xfs_ioctl32.c | 1 fs/xfs/linux-2.6/xfs_iops.c | 1 fs/xfs/linux-2.6/xfs_linux.h | 1 fs/xfs/linux-2.6/xfs_lrw.c | 87 -- fs/xfs/linux-2.6/xfs_lrw.h | 45 - fs/xfs/linux-2.6/xfs_super.c | 104 --- fs/xfs/linux-2.6/xfs_super.h | 7 fs/xfs/linux-2.6/xfs_sync.c | 1 fs/xfs/linux-2.6/xfs_trace.c | 75 ++ fs/xfs/linux-2.6/xfs_trace.h | 1369 +++++++++++++++++++++++++++++++++++++++++ fs/xfs/linux-2.6/xfs_vnode.h | 4 fs/xfs/quota/xfs_dquot.c | 110 --- fs/xfs/quota/xfs_dquot.h | 21 fs/xfs/quota/xfs_qm.c | 40 - fs/xfs/quota/xfs_qm_syscalls.c | 4 fs/xfs/support/ktrace.c | 323 --------- fs/xfs/support/ktrace.h | 85 -- fs/xfs/xfs.h | 16 fs/xfs/xfs_ag.h | 14 fs/xfs/xfs_alloc.c | 230 +----- fs/xfs/xfs_alloc.h | 27 fs/xfs/xfs_alloc_btree.c | 1 fs/xfs/xfs_attr.c | 107 --- fs/xfs/xfs_attr.h | 10 fs/xfs/xfs_attr_leaf.c | 14 fs/xfs/xfs_attr_sf.h | 40 - fs/xfs/xfs_bmap.c | 507 +++------------ fs/xfs/xfs_bmap.h | 49 - fs/xfs/xfs_bmap_btree.c | 6 fs/xfs/xfs_btree.c | 5 fs/xfs/xfs_btree_trace.h | 17 fs/xfs/xfs_buf_item.c | 87 -- fs/xfs/xfs_buf_item.h | 20 fs/xfs/xfs_da_btree.c | 3 fs/xfs/xfs_da_btree.h | 7 fs/xfs/xfs_dfrag.c | 2 fs/xfs/xfs_dir2.c | 8 fs/xfs/xfs_dir2_block.c | 20 fs/xfs/xfs_dir2_leaf.c | 21 fs/xfs/xfs_dir2_node.c | 27 fs/xfs/xfs_dir2_sf.c | 26 fs/xfs/xfs_dir2_trace.c | 216 ------ fs/xfs/xfs_dir2_trace.h | 72 -- fs/xfs/xfs_filestream.c | 8 fs/xfs/xfs_fsops.c | 2 fs/xfs/xfs_iget.c | 111 --- fs/xfs/xfs_inode.c | 67 -- fs/xfs/xfs_inode.h | 76 -- fs/xfs/xfs_inode_item.c | 5 fs/xfs/xfs_iomap.c | 85 -- fs/xfs/xfs_iomap.h | 8 fs/xfs/xfs_log.c | 181 +---- fs/xfs/xfs_log_priv.h | 20 fs/xfs/xfs_log_recover.c | 1 fs/xfs/xfs_mount.c | 2 fs/xfs/xfs_quota.h | 8 fs/xfs/xfs_rename.c | 1 fs/xfs/xfs_rtalloc.c | 1 fs/xfs/xfs_rw.c | 3 fs/xfs/xfs_trans.h | 47 + fs/xfs/xfs_trans_buf.c | 62 - fs/xfs/xfs_vnodeops.c | 8 70 files changed, 2151 insertions(+), 2592 deletions(-) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2009-03-16xfs: factor out code to find the longest free extent in the AGDave Chinner
Signed-off-by: Dave Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2008-12-01[XFS] factor out xfs_read_agf helperFrom: Christoph Hellwig
Add a helper to read the AGF header and perform basic verification. Based on hunks from a larger patch from Dave Chinner. (First sent on Juli 23rd) Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Niv Sardi <xaiki@sgi.com>