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* xfs: Introduce delayed logging core codeDave Chinner2010-05-2411-30/+912
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The delayed logging code only changes in-memory structures and as such can be enabled and disabled with a mount option. Add the mount option and emit a warning that this is an experimental feature that should not be used in production yet. We also need infrastructure to track committed items that have not yet been written to the log. This is what the Committed Item List (CIL) is for. The log item also needs to be extended to track the current log vector, the associated memory buffer and it's location in the Commit Item List. Extend the log item and log vector structures to enable this tracking. To maintain the current log format for transactions with delayed logging, we need to introduce a checkpoint transaction and a context for tracking each checkpoint from initiation to transaction completion. This includes adding a log ticket for tracking space log required/used by the context checkpoint. To track all the changes we need an io vector array per log item, rather than a single array for the entire transaction. Using the new log vector structure for this requires two passes - the first to allocate the log vector structures and chain them together, and the second to fill them out. This log vector chain can then be passed to the CIL for formatting, pinning and insertion into the CIL. Formatting of the log vector chain is relatively simple - it's just a loop over the iovecs on each log vector, but it is made slightly more complex because we re-write the iovec after the copy to point back at the memory buffer we just copied into. This code also needs to pin log items. If the log item is not already tracked in this checkpoint context, then it needs to be pinned. Otherwise it is already pinned and we don't need to pin it again. The only other complexity is calculating the amount of new log space the formatting has consumed. This needs to be accounted to the transaction in progress, and the accounting is made more complex becase we need also to steal space from it for log metadata in the checkpoint transaction. Calculate all this at insert time and update all the tickets, counters, etc correctly. Once we've formatted all the log items in the transaction, attach the busy extents to the checkpoint context so the busy extents live until checkpoint completion and can be processed at that point in time. Transactions can then be freed at this point in time. Now we need to issue checkpoints - we are tracking the amount of log space used by the items in the CIL, so we can trigger background checkpoints when the space usage gets to a certain threshold. Otherwise, checkpoints need ot be triggered when a log synchronisation point is reached - a log force event. Because the log write code already handles chained log vectors, writing the transaction is trivial, too. Construct a transaction header, add it to the head of the chain and write it into the log, then issue a commit record write. Then we can release the checkpoint log ticket and attach the context to the log buffer so it can be called during Io completion to complete the checkpoint. We also need to allow for synchronising multiple in-flight checkpoints. This is needed for two things - the first is to ensure that checkpoint commit records appear in the log in the correct sequence order (so they are replayed in the correct order). The second is so that xfs_log_force_lsn() operates correctly and only flushes and/or waits for the specific sequence it was provided with. To do this we need a wait variable and a list tracking the checkpoint commits in progress. We can walk this list and wait for the checkpoints to change state or complete easily, an this provides the necessary synchronisation for correct operation in both cases. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: Delayed logging design documentationDave Chinner2010-05-241-0/+816
| | | | | | | | | | | | Document the design of the delayed logging implementation. This includes assumptions made, dead ends followed, the reasoning behind the structuring of the code, the layout of various structures, how things fit together, traps and pit-falls avoided, etc. This is all too much to document in the code itself, so do it in a separate file. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: Improve scalability of busy extent trackingDave Chinner2010-05-2411-322/+350
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* xfs: make the log ticket ID available outside the log infrastructureDave Chinner2010-05-244-3/+12
| | | | | | | | | | | | | | | | The ticket ID is needed to uniquely identify transactions when doing busy extent matching. Delayed logging changes the lifecycle of busy extents with respect to the transaction structure lifecycle. Hence we can no longer use the transaction structure as a means of determining the owner of the busy extent as it may be freed and reused while the busy extent is still active. This commit provides the infrastructure to access the xlog_tid_t held in the ticket from a transaction handle. This avoids the need for callers to peek into the transaction and log structures to find this out. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: clean up log ticket overrun debug outputDave Chinner2010-05-242-15/+6
| | | | | | | | | | | Push the error message output when a ticket overrun is detected into the ticket printing functions. Also remove the debug version of the code as the production version will still panic just as effectively on a debug kernel via the panic mask being set. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: Clean up XFS_BLI_* flag namespaceDave Chinner2010-05-247-70/+70
| | | | | | | | | | | | | Clean up the buffer log format (XFS_BLI_*) flags because they have a polluted namespace. They XFS_BLI_ prefix is used for both in-memory and on-disk flag feilds, but have overlapping values for different flags. Rename the buffer log format flags to use the XFS_BLF_* prefix to avoid confusing them with the in-memory XFS_BLI_* prefixed flags. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: modify buffer item reference countingDave Chinner2010-05-241-60/+50
| | | | | | | | | | | | | | | | | | | | The buffer log item reference counts used to take referenceѕ for every transaction, similar to the pin counting. This is symmetric (like the pin/unpin) with respect to transaction completion, but with dleayed logging becomes assymetric as the pinning becomes assymetric w.r.t. transaction completion. To make both cases the same, allow the buffer pinning to take a reference to the buffer log item and always drop the reference the transaction has on it when being unlocked. This is balanced correctly because the unpin operation always drops a reference to the log item. Hence reference counting becomes symmetric w.r.t. item pinning as well as w.r.t active transactions and as a result the reference counting model remain consistent between normal and delayed logging. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: allow log ticket allocation to take allocation flagsDave Chinner2010-05-241-8/+8
| | | | | | | | | | | | Delayed logging currently requires ticket allocation to succeed, so we need to be able to sleep on allocation. It also should not allow memory allocation to recurse into the filesystem. hence we need to pass allocation flags directing the type of allocation the caller requires. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: Don't reuse the same transaction ID for duplicated transactions.Dave Chinner2010-05-241-0/+9
| | | | | | | | | | | | | | | | The transaction ID is written into the log as the unique identifier for transactions during recover. When duplicating a transaction, we reuse the log ticket, which means it has the same transaction ID as the previous transaction. Rather than regenerating a random transaction ID for the duplicated transaction, just add one to the current ID so that duplicated transaction can be easily spotted in the log and during recovery during problem diagnosis. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: mark xfs_iomap_write_ helpers staticChristoph Hellwig2010-05-192-13/+13
| | | | | | | And also drop a useless argument to xfs_iomap_write_direct. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: clean up end index calculation in xfs_page_state_convertChristoph Hellwig2010-05-191-8/+15
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: clean up mapping size calculation in __xfs_get_blocksChristoph Hellwig2010-05-191-9/+16
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: clean up xfs_iomap_validChristoph Hellwig2010-05-191-23/+23
| | | | | | | | | | Rename all iomap_valid identifiers to imap_valid to fit the new world order, and clean up xfs_iomap_valid to convert the passed in offset to blocks instead of the imap values to bytes. Use the simpler inode->i_blkbits instead of the XFS macros for this. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: move I/O type flags into xfs_aops.cChristoph Hellwig2010-05-192-29/+30
| | | | | | | | | The IOMAP_ flags are now only used inside xfs_aops.c for extent probing and I/O completion tracking, so more them here, and rename them to IO_* as there's no mapping involved at all. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: kill struct xfs_iomapChristoph Hellwig2010-05-193-123/+75
| | | | | | | | | | Now that struct xfs_iomap contains exactly the same units as struct xfs_bmbt_irec we can just use the latter directly in the aops code. Replace the missing IOMAP_NEW flag with a new boolean output parameter to xfs_iomap. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: report iomap_bn in block baseChristoph Hellwig2010-05-193-26/+16
| | | | | | | | | | Report the iomap_bn field of struct xfs_iomap in terms of filesystem blocks instead of in terms of bytes. Shift the byte conversions into the caller, and replace the IOMAP_DELAY and IOMAP_HOLE flag checks with checks for HOLESTARTBLOCK and DELAYSTARTBLOCK. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: report iomap_offset and iomap_bsize in block baseChristoph Hellwig2010-05-192-14/+27
| | | | | | | | | | Report the iomap_offset and iomap_bsize fields of struct xfs_iomap in terms of fsblocks instead of in terms of disk blocks. Shift the byte conversions into the callers temporarily, but they will disappear or get cleaned up later. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: remove iomap_deltaChristoph Hellwig2010-05-193-4/+4
| | | | | | | | | The iomap_delta field in struct xfs_iomap just contains the difference between the offset passed to xfs_iomap and the iomap_offset. Just calculate it in the only caller that cares. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: remove iomap_targetChristoph Hellwig2010-05-193-29/+18
| | | | | | | | | | | Instead of using the iomap_target field in struct xfs_iomap and the IOMAP_REALTIME flag just use the already existing xfs_find_bdev_for_inode helper. There's some fallout as we need to pass the inode in a few more places, which we also use to sanitize some calling conventions. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: limit xfs_imap_to_bmap to a single mappingChristoph Hellwig2010-05-191-36/+28
| | | | | | | | | We only call xfs_iomap for single mappings anyway, so remove all code dealing with multiple mappings from xfs_imap_to_bmap and add asserts that we never get results that we do not expect. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: simplify buffer to transaction matchingChristoph Hellwig2010-05-191-138/+46
| | | | | | | | | | | | | | | | | We currenly have a routine xfs_trans_buf_item_match_all which checks if any log item in a transaction contains a given buffer, and a second one that only does this check for the first, embedded chunk of log items. We only use the second routine if we know we only have that log item chunk, so get rid of the limited routine and always use the more complete one. Also rename the old xfs_trans_buf_item_match_all to xfs_trans_buf_item_match and update various surrounding comments, and move the remaining xfs_trans_buf_item_match on top of the file to avoid a forward prototype. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: Make fiemap work in query mode.Tao Ma2010-05-191-1/+4
| | | | | | | | | | | | | | | | | | | | According to Documentation/filesystems/fiemap.txt, If fm_extent_count is zero, then the fm_extents[] array is ignored (no extents will be returned), and the fm_mapped_extents count will hold the number of extents needed. But as the commit 97db39a1f6f69e906e98118392400de5217aa33a has changed bmv_count to the caller's input buffer, this number query function can't work any more. As this commit is written to change bmv_count from MAXEXTNUM because of ENOMEM. This patch just try to set bm.bmv_count to something sane. Thanks to Dave Chinner <david@fromorbit.com> for the suggestion. Cc: Eric Sandeen <sandeen@redhat.com> Cc: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Tao Ma <tao.ma@oracle.com>
* xfs: kill off l_sectbb_maskAlex Elder2010-05-193-9/+10
| | | | | | | | | | | | | There remains only one user of the l_sectbb_mask field in the log structure. Just kill it off and compute the mask where needed from the power-of-2 sector size. (Only update from last post is to accomodate the changes in the previous patch in the series.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: record log sector size rather than log2(that)Alex Elder2010-05-193-31/+31
| | | | | | | | | | | | | | | | | Change struct log so it keeps track of the size (in basic blocks) of a log sector in l_sectBBsize rather than the log-base-2 of that value (previously, l_sectbb_log). The name was chosen for consistency with the other fields in the structure that represent a number of basic blocks. (Updated so that a variable used in computing and verifying a log's sector size is named "log2_size". Also added the "BB" to the structure field name, based on feedback from Eric Sandeen. Also dropped some superfluous parentheses.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
* xfs: remove dead XFS_LOUD_RECOVERY codeChristoph Hellwig2010-05-193-82/+0
| | | | | | | | | | This can't be enabled through the build system and has been dead for ages. Note that the CRC patches add back log checksumming, but the code is quite different from the version removed here anyway. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
* xfs: removed unused XFS_QMOPT_ flagsChristoph Hellwig2010-05-193-6/+3
| | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
* xfs: remove a few macro indirections in the quota codeChristoph Hellwig2010-05-194-31/+25
| | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
* xfs: access quotainfo structure directlyChristoph Hellwig2010-05-196-172/+165
| | | | | | | | | | Access fields in m_quotainfo directly instead of hiding them behind the XFS_QI_* macros. Add local variables for the quotainfo pointer in places where we have lots of them. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
* xfs: wait for direct I/O to complete in fsync and write_inodeChristoph Hellwig2010-05-192-0/+3
| | | | | | | | | We need to wait for all pending direct I/O requests before taking care of metadata in fsync and write_inode. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
* xfs: xfs_trace.c: duplicated includeAndrea Gelmini2010-05-191-1/+0
| | | | | | | fs/xfs/linux-2.6/xfs_trace.c: xfs_attr_sf.h is included more than once. Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: minor odds and ends in xfs_log_recover.cAlex Elder2010-05-191-16/+15
| | | | | | | | | | | | | | | | | | Odds and ends in "xfs_log_recover.c". This patch just contains some minor things that didn't seem to warrant their own individual patches: - In xlog_bread_noalign(), drop an assertion that a pointer is non-null (the crash will tell us it was a bad pointer). - Add a more descriptive header comment for xlog_find_verify_cycle(). - Make a few additions to the comments in xlog_find_head(). Also rearrange some expressions in a few spots to produce the same result, but in a way that seems more clear what's being computed. (Updated in response to Dave's review comments. Note I did not split this patch like I said I would.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: avoid repeated pointer dereferencesAlex Elder2010-05-191-12/+13
| | | | | | | | | | | In xlog_find_cycle_start() use a local variable for some repeated operations rather than constantly accessing the memory location whose address is passed in. (This version drops an assertion that a pointer is non-null.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: change a few labels in xfs_log_recover.cAlex Elder2010-05-191-11/+9
| | | | | | | | | | | Rename a label used in xlog_find_head() that I thought was poorly chosen. Also combine two adjacent labels xlog_find_tail() into a single label, and give it a more generic name. (Now using Dave's suggested "validate_head" name for first label.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: enforce synchronous writes in xfs_bwriteChristoph Hellwig2010-05-192-12/+6
| | | | | | | | | | | | | xfs_bwrite is used with the intention of synchronously writing out buffers, but currently it does not actually clear the async flag if that's left from previous writes but instead implements async behaviour if it finds it. Remove the code handling asynchronous writes as we've got rid of those entirely outside of the log and delwri buffers, and make sure that we clear the async and read flags before writing the buffer. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: remove periodic superblock writebackChristoph Hellwig2010-05-191-63/+27
| | | | | | | | | | | | | | All modifications to the superblock are done transactional through xfs_trans_log_buf, so there is no reason to initiate periodic asynchronous writeback. This only removes the superblock from the delwri list and will lead to sub-optimal I/O scheduling. Cut down xfs_sync_fsdata now that it's only used for synchronous superblock writes and move the log coverage checks into the two callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
* xfs: make the log ticket transaction id randomDave Chinner2010-05-191-1/+1
| | | | | | | | | | | | | | | | | | The transaction ID that is written to the log for a transaction is currently set by taking the lower 32 bits of the memory address of the ticket structure. This is not guaranteed to be unique as tickets comes from a slab and slots can be reallocated immediately after being freed. As a result, there is no guarantee of uniqueness in the ticket ID value. Fix this by assigning a random number to the ticket ID field so that it is extremely unlikely that duplicates will occur and remove the possibility of transactions being mixed up during recovery due to duplicate IDs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: nothing special about 1-block log sectorAlex Elder2010-05-191-13/+29
| | | | | | | | | | | There are a number of places where a log sector size of 1 uses special case code. The round_up() and round_down() macros produce the correct result even when the log sector size is 1, and this eliminates the need for treating this as a special case. Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: encapsulate bbcount validity checkingAlex Elder2010-05-191-12/+26
| | | | | | | | | | | | Define a function that encapsulates checking the validity of a log block count. (Updated from previous version--no longer includes error reporting in the encapsulated validation function.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com>
* xfs: kill XLOG_SECTOR_ROUND*()Alex Elder2010-05-191-14/+9
| | | | | | | | | | | | | | | | | XLOG_SECTOR_ROUNDUP_BBCOUNT() and XLOG_SECTOR_ROUNDDOWN_BLKNO() are now fairly simple macro translations. Just get rid of them in favor of the round_up() and round_down() macro calls they represent. Also, in spots in xlog_get_bp() and xlog_write_log_records(), round_up() was being called with value 1, which just evaluates to the macro's second argument; so just use that instead. In the latter case, make use of that value, as long as it's already been computed. Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com>
* xfs: simplify XLOG_SECTOR_ROUND*()Alex Elder2010-05-191-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | XLOG_SECTOR_ROUNDUP_BBCOUNT() is defined in "fs/xfs/xfs_log_recover.c" in an overly-complicated way. It is basically roundup(), but that is not at all clear from its definition. (Actually, there is another macro round_up() that applies for power-of-two-based masks which I'll be using here.) The operands in XLOG_SECTOR_ROUNDUP_BBCOUNT() are basically the block number (bbs) and the log sector basic block mask (log->l_sectbb_mask). I'll call them B and M for this discussion. The macro computes is value this way: M && (B & M) ? (B + M + 1) & ~M : B Put another way, we can break it into 3 cases: 1) ! M -> B # 0 mask, no effect 2) ! (B & M) -> B # sector aligned 3) M && (B & M) -> (B + M + 1) & ~M # round up otherwise The round_up() macro is cleverly defined using a value, v, and a power-of-2, p, and the result is the nearest multiple of p greater than or equal to v. Its value is computed something like this: ((v - 1) | (p - 1)) + 1 Let's consider using this in the context of the 3 cases above. When p = 2^0 = 1, the result boils down to ((v - 1) | 0) + 1, so it just translates any value v to itself. That handles case (1) above. When p = 2^n, n > 0, we know that (p - 1) will be a mask with all n bits 0..n-1 set. The condition in this case occurs when none of those mask bits is set in the value v provided. If that is the case, subtracting 1 from v will have 1's in all those lower bits (at least). Therefore, OR-ing the mask with that decremented value has no effect, so adding the 1 back again will just translate the v to itself. This handles case (2). Otherwise, the value v is greater than some multiple of p, and decrementing it will produce a result greater than or equal to that multiple. OR-ing in the mask will produce a value 1 less than the next multiple of p, so finally adding 1 back will result in the desired rounded-up value. This handles case (3). Hopefully this is convincing. While I was at it, I converted XLOG_SECTOR_ROUNDDOWN_BLKNO() to use the round_down() macro. Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com>
* xfs: fix min bufsize bugs in two placesAlex Elder2010-05-191-4/+17
| | | | | | | | | | | | | | | | | | | | | | This fixes a bug in two places that I found by inspection. In xlog_find_verify_cycle() and xlog_write_log_records(), the code attempts to allocate a buffer to hold as many blocks as possible. It gives up if the number of blocks to be allocated gets too small. Right now it uses log->l_sectbb_log as that lower bound, but I'm sure it's supposed to be the actual log sector size instead. That is, the lower bound should be (1 << log->l_sectbb_log). Also define a simple macro xlog_sectbb(log) to represent the number of basic blocks in a sector for the given log. (No change from original submission; I have implemented Christoph's suggestion about storing l_sectsize rather than l_sectbb_log in a new, separate patch in this series.) Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com>
* xfs: add const qualifiers to xfs error function argsAlex Elder2010-05-192-19/+20
| | | | | | | | | | Change the tag and file name arguments to xfs_error_report() and xfs_corruption_error() to use a const qualifier. Signed-off-by: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com>
* xfs: remove xfs_dqmarkerChristoph Hellwig2010-05-192-21/+2
| | | | | | | | The xfs_dqmarker structure does not need to exist anymore. Move the remaining flags field out of it and remove the structure altogether. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
* xfs: convert the dquot free list to use list headsDave Chinner2010-05-196-165/+72
| | | | | | | | | Convert the dquot free list on the filesystem to use listhead infrastructure rather than the roll-your-own in the quota code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: convert the dquot hash list to use list headsDave Chinner2010-05-196-88/+30
| | | | | | | | Convert the dquot hash list on the filesystem to use listhead infrastructure rather than the roll-your-own in the quota code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: remove duplicate code from dquot reclaimDave Chinner2010-05-192-193/+73
| | | | | | | | | | The dquot shaker and the free-list reclaim code use exactly the same algorithm but the code is duplicated and slightly different in each case. Make the shaker code use the single dquot reclaim code to remove the code duplication. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: convert the per-mount dquot list to use list headsDave Chinner2010-05-196-112/+97
| | | | | | | | Convert the dquot list on the filesytesm to use listhead infrastructure rather than the roll-your-own in the quota code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: add log item recovery tracingDave Chinner2010-05-195-9/+187
| | | | | | | | | | | | | | Currently there is no tracing in log recovery, so it is difficult to determine what is going on when something goes wrong. Add tracing for log item recovery to provide visibility into the log recovery process. The tracing added shows regions being extracted from the log transactions and added to the transaction hash forming recovery items, followed by the reordering, cancelling and finally recovery of the items. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* xfs: clean up xlog_write_adv_cntChristoph Hellwig2010-05-192-27/+27
| | | | | | | | | | | | Replace the awkward xlog_write_adv_cnt with an inline helper that makes it more obvious that it's modifying it's paramters, and replace the use of an integer type for "ptr" with a real void pointer. Also move xlog_write_adv_cnt to xfs_log_priv.h as it will be used outside of xfs_log.c in the delayed logging series. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com>
* xfs: introduce new internal log vector structureDave Chinner2010-05-192-59/+90
| | | | | | | | | | | | | | | | | | The current log IO vector structure is a flat array and not extensible. To make it possible to keep separate log IO vectors for individual log items, we need a method of chaining log IO vectors together. Introduce a new log vector type that can be used to wrap the existing log IO vectors on use that internally to the log. This means that the existing external interface (xfs_log_write) does not change and hence no changes to the transaction commit code are required. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
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