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2010-03-05pass writeback_control to ->write_inodeChristoph Hellwig
This gives the filesystem more information about the writeback that is happening. Trond requested this for the NFS unstable write handling, and other filesystems might benefit from this too by beeing able to distinguish between the different callers in more detail. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-05make sure data is on disk before calling ->write_inodeChristoph Hellwig
Similar to the fsync issue fixed a while ago in commit 2daea67e966dc0c42067ebea015ddac6834cef88 we need to write for data to actually hit the disk before writing out the metadata to guarantee data integrity for filesystems that modify the inode in the data I/O completion path. Currently XFS and NFS handle this manually, and AFS has a write_inode method that does nothing but waiting for data, while others are possibly missing out on this. Fortunately this change has a lot less impact than the fsync change as none of the write_inode methods starts data writeout of any form by itself. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: add __percpu sparse annotations to what's left percpu: add __percpu sparse annotations to fs percpu: add __percpu sparse annotations to core kernel subsystems local_t: Remove leftover local.h this_cpu: Remove pageset_notifier this_cpu: Page allocator conversion percpu, x86: Generic inc / dec percpu instructions local_t: Move local.h include to ringbuffer.c and ring_buffer_benchmark.c module: Use this_cpu_xx to dynamically allocate counters local_t: Remove cpu_local_xx macros percpu: refactor the code in pcpu_[de]populate_chunk() percpu: remove compile warnings caused by __verify_pcpu_ptr() percpu: make accessors check for percpu pointer in sparse percpu: add __percpu for sparse. percpu: make access macros universal percpu: remove per_cpu__ prefix.
2010-02-26Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfsLinus Torvalds
* 'for-linus' of git://oss.sgi.com/xfs/xfs: (52 commits) fs/xfs: Correct NULL test xfs: optimize log flushing in xfs_fsync xfs: only clear the suid bit once in xfs_write xfs: kill xfs_bawrite xfs: log changed inodes instead of writing them synchronously xfs: remove invalid barrier optimization from xfs_fsync xfs: kill the unused XFS_QMOPT_* flush flags V2 xfs: Use delay write promotion for dquot flushing xfs: Sort delayed write buffers before dispatch xfs: Don't issue buffer IO direct from AIL push V2 xfs: Use delayed write for inodes rather than async V2 xfs: Make inode reclaim states explicit xfs: more reserved blocks fixups xfs: turn off sign warnings xfs: don't hold onto reserved blocks on remount,ro xfs: quota limit statvfs available blocks xfs: replace KM_LARGE with explicit vmalloc use xfs: cleanup up xfs_log_force calling conventions xfs: kill XLOG_VEC_SET_TYPE xfs: remove duplicate buffer flags ...
2010-02-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/xfs-viptLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/xfs-vipt: xfs: fix xfs to work with Virtually Indexed architectures sh: add mm API for DMA to vmalloc/vmap areas arm: add mm API for DMA to vmalloc/vmap areas parisc: add mm API for DMA to vmalloc/vmap areas mm: add coherence API for DMA to vmalloc/vmap areas
2010-02-17percpu: add __percpu sparse annotations to fsTejun Heo
Add __percpu sparse annotations to fs. These annotations are to make sparse consider percpu variables to be in a different address space and warn if accessed without going through percpu accessors. This patch doesn't affect normal builds. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Alex Elder <aelder@sgi.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
2010-02-13fs/xfs: Correct NULL testJulia Lawall
Test the value that was just allocated rather than the previously tested one. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @r@ expression *x; expression e; identifier l; @@ if (x == NULL || ...) { ... when forall return ...; } ... when != goto l; when != x = e when != &x *x == NULL // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-02-12xfs: optimize log flushing in xfs_fsyncChristoph Hellwig
If we have a pinned inode it must have a log item attached to it. Usually that log item will have ili_last_lsn already set, in which case we only need to flush the log up to that LSN instead of doing a full log force. This gives speedups of about 5% in some fsync heavy workloads. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-02-12xfs: only clear the suid bit once in xfs_writeChristoph Hellwig
file_remove_suid already calls into ->setattr to clear the suid and sgid bits if needed, no need to start a second transaction to do it ourselves. Note that xfs_write_clear_setuid issues a sync transaction while the path through ->setattr doesn't, but that is consistant with the other filesystems. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Alex Elder <aelder@sgi.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-02-05xfs: fix xfs to work with Virtually Indexed architecturesJames Bottomley
xfs_buf.c includes what is essentially a hand rolled version of blk_rq_map_kern(). In order to work properly with the vmalloc buffers that xfs uses, this hand rolled routine must also implement the flushing API for vmap/vmalloc areas. [style updates from hch@lst.de] Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2010-02-04xfs: kill xfs_bawriteDave Chinner
There are no more users of this function left in the XFS code now that we've switched everything to delayed write flushing. Remove it. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-02-09xfs: log changed inodes instead of writing them synchronouslyChristoph Hellwig
When an inode has already be flushed delayed write, xfs_inode_clean() returns true and hence xfs_fs_write_inode() can return on a synchronous inode write without having written the inode. Currently these sycnhronous writes only come sync(1), unmount, a sycnhronous NFS export and cachefiles so should be relatively rare and out of common performance paths. Realistically, a synchronous inode write is not necessary here; we can avoid writing the inode by logging any non-transactional changes that are pending. This needs to be done with synchronous transactions, but it avoids seeking between the log and inode clusters as we do now. We don't force the log if the inode is pinned, though, so this differs from the fsync case. For normal sys_sync and unmount behaviour this is fine because we do a synchronous log force in xfs_sync_data which is called from the ->sync_fs code. It does however break the NFS synchronous export guarantees for now, but work is under way to fix this at a higher level or for the higher level to provide an additional flag in the writeback control to tell us that a log force is needed. Portions of this patch are based on work from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Alex Elder <aelder@sgi.com>
2010-02-02xfs: remove invalid barrier optimization from xfs_fsyncChristoph Hellwig
We always need to flush the disk write cache and can't skip it just because the no inode attributes have changed. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com>
2010-02-04xfs: kill the unused XFS_QMOPT_* flush flags V2Dave Chinner
dquots are never flushed asynchronously. Remove the flag and the async write support from the flush function. Make the default flush a delwri flush to make the inode flush code, which leaves the XFS_QMOPT_SYNC the only flag remaining. Convert that to use SYNC_WAIT instead, just like the inode flush code. V2: - just pass flush flags straight through Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-26xfs: Use delay write promotion for dquot flushingDave Chinner
xfs_qm_dqflock_pushbuf_wait() does a very similar trick to item pushing used to do to flush out delayed write dquot buffers. Change it to use the new promotion method rather than an async flush. Also, xfs_qm_dqflock_pushbuf_wait() can return without the flush lock held, yet the callers make the assumption that after this call the flush lock is held. Always return with the flush lock held. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-26xfs: Sort delayed write buffers before dispatchDave Chinner
Currently when the xfsbufd writes delayed write buffers, it pushes them to disk in the order they come off the delayed write list. If there are lots of buffers ѕpread widely over the disk, this results in overwhelming the elevator sort queues in the block layer and we end up losing the posibility of merging adjacent buffers to minimise the number of IOs. Use the new generic list_sort function to sort the delwri dispatch queue before issue to ensure that the buffers are pushed in the most friendly order possible to the lower layers. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-02-02xfs: Don't issue buffer IO direct from AIL push V2Dave Chinner
All buffers logged into the AIL are marked as delayed write. When the AIL needs to push the buffer out, it issues an async write of the buffer. This means that IO patterns are dependent on the order of buffers in the AIL. Instead of flushing the buffer, promote the buffer in the delayed write list so that the next time the xfsbufd is run the buffer will be flushed by the xfsbufd. Return the state to the xfsaild that the buffer was promoted so that the xfsaild knows that it needs to cause the xfsbufd to run to flush the buffers that were promoted. Using the xfsbufd for issuing the IO allows us to dispatch all buffer IO from the one queue. This means that we can make much more enlightened decisions on what order to flush buffers to disk as we don't have multiple places issuing IO. Optimisations to xfsbufd will be in a future patch. Version 2 - kill XFS_ITEM_FLUSHING as it is now unused. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-02-06xfs: Use delayed write for inodes rather than async V2Dave Chinner
We currently do background inode flush asynchronously, resulting in inodes being written in whatever order the background writeback issues them. Not only that, there are also blocking and non-blocking asynchronous inode flushes, depending on where the flush comes from. This patch completely removes asynchronous inode writeback. It removes all the strange writeback modes and replaces them with either a synchronous flush or a non-blocking delayed write flush. That is, inode flushes will only issue IO directly if they are synchronous, and background flushing may do nothing if the operation would block (e.g. on a pinned inode or buffer lock). Delayed write flushes will now result in the inode buffer sitting in the delwri queue of the buffer cache to be flushed by either an AIL push or by the xfsbufd timing out the buffer. This will allow accumulation of dirty inode buffers in memory and allow optimisation of inode cluster writeback at the xfsbufd level where we have much greater queue depths than the block layer elevators. We will also get adjacent inode cluster buffer IO merging for free when a later patch in the series allows sorting of the delayed write buffers before dispatch. This effectively means that any inode that is written back by background writeback will be seen as flush locked during AIL pushing, and will result in the buffers being pushed from there. This writeback path is currently non-optimal, but the next patch in the series will fix that problem. A side effect of this delayed write mechanism is that background inode reclaim will no longer directly flush inodes, nor can it wait on the flush lock. The result is that inode reclaim must leave the inode in the reclaimable state until it is clean. Hence attempts to reclaim a dirty inode in the background will simply skip the inode until it is clean and this allows other mechanisms (i.e. xfsbufd) to do more optimal writeback of the dirty buffers. As a result, the inode reclaim code has been rewritten so that it no longer relies on the ambiguous return values of xfs_iflush() to determine whether it is safe to reclaim an inode. Portions of this patch are derived from patches by Christoph Hellwig. Version 2: - cleanup reclaim code as suggested by Christoph - log background reclaim inode flush errors - just pass sync flags to xfs_iflush Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-02-06xfs: Make inode reclaim states explicitDave Chinner
A.K.A.: don't rely on xfs_iflush() return value in reclaim We have gradually been moving checks out of the reclaim code because they are duplicated in xfs_iflush(). We've had a history of problems in this area, and many of them stem from the overloading of the return values from xfs_iflush() and interaction with inode flush locking to determine if the inode is safe to reclaim. With the desire to move to delayed write flushing of inodes and non-blocking inode tree reclaim walks, the overloading of the return value of xfs_iflush makes it very difficult to determine the correct thing to do next. This patch explicitly re-adds the checks to the inode reclaim code, removing the reliance on the return value of xfs_iflush() to determine what to do next. It also means that we can clearly document all the inode states that reclaim must handle and hence we can easily see that we handled all the necessary cases. This also removes the need for the xfs_inode_clean() check in xfs_iflush() as all callers now check this first (safely). Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-02-08xfs: more reserved blocks fixupsEric Sandeen
This mangles the reserved blocks counts a little more. 1) add a helper function for the default reserved count 2) add helper functions to save/restore counts on ro/rw 3) save/restore reserved blocks on freeze/thaw 4) disallow changing reserved count while readonly V2: changed field name to match Dave's changes Signed-off-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-26xfs: turn off sign warningsDave Chinner
Because they cause warnings in static inline functions conditionally compiled into XFS from the VFS (e.g. fsnotify). Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-26xfs: don't hold onto reserved blocks on remount,roDave Chinner
If we hold onto reserved blocks when doing a remount,ro we end up writing the blocks used count to disk that includes the reserved blocks. Reserved blocks are not actually used, so this results in the values in the superblock being incorrect. Hence if we run xfs_check or xfs_repair -n while the filesystem is mounted remount,ro we end up with an inconsistent filesystem being reported. Also, running xfs_copy on the remount,ro filesystem will result in an inconsistent image being generated. To fix this, unreserve the blocks when doing the remount,ro, and reserved them again on remount,rw. This way a remount,ro filesystem will appear consistent on disk to all utilities. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-21xfs: quota limit statvfs available blocksChristoph Hellwig
A "df" run on an NFS client of an exported XFS file system reports the wrong information for "available" blocks. When a block quota is enforced, the amount reported as free is limited by the quota, but the amount reported available is not (and should be). Reported-by: Guk-Bong, Kwon <gbkwon@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21xfs: replace KM_LARGE with explicit vmalloc useChristoph Hellwig
We use the KM_LARGE flag to make kmem_alloc and friends use vmalloc if necessary. As we only need this for a few boot/mount time allocations just switch to explicit vmalloc calls there. Signed-off-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: kill XLOG_VEC_SET_TYPEChristoph Hellwig
This macro only obsfucates the log item type assignments, so kill it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21xfs: 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>
2010-01-21xfs: implement quota warnings via netlinkChristoph Hellwig
Wire up quota_send_warning to send quota warnings over netlink. This is used by various desktops to show user quota warnings. Tested by running the quota_nld daemon while running the xfstest quota tests and observing the warnings. I'll see how I can get a more formal testcase for it written. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21xfs: clean up error handling in xfs_trans_dqresvChristoph Hellwig
Move the error code selection after the goto label and fold the xfs_quota_error helper into it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21xfs: kill XFS_QMOPT_ASYNCChristoph Hellwig
The option is unused and one of the few remaining users of xfs_bawrite, so let's get rid of it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-20xfs: rearrange xfs_mod_sb() to avoid array subscript warningDave Chinner
gcc warns of an array subscript out of bounds in xfs_mod_sb(). The code is written in such a way that if the array subscript is out of bounds, then it will assert fail. Rearrange the code to avoid the bounds check warning. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: suppress spurious uninitialised var warning in xfs_bmapi()Dave Chinner
Initialise the xfs_bmalloca_t structure to zero to avoid uninitialised variable warnings. This is done by zeroing the arg structure rather than using the uninitialised_var() trick so we know for certain that the structure is correctly initialised as xfs_bmapi is a very complex function and it is difficult to prove warnings are spurious. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: make compile warn about char sign mismatches againDave Chinner
The -fno-unsigned-char directive has no effect anymore as the XFs build is clean. However, the kernel build hides pointer sign differences so turn that back on so that we can clean up all the mismatches prior to a userspace code resync. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: clean up sign warnings in dir2 codeDave Chinner
We are now consistently using unsigned char strings for names so fix up the remaining warnings in the dir2 code to complete the cleanup. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: convert attr to use unsigned namesDave Chinner
To be consistent with the directory code, the attr code should use unsigned names. Convert the names from the vfs at the highest level to unsigned, and ænsure they are consistenly used as unsigned down to disk. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: xfs_buf_iomove() doesn't care about signednessDave Chinner
xfs_buf_iomove() uses xfs_caddr_t as it's parameter types, but it doesn't care about the signedness of the variables as it is just copying the data. Change the prototype to use void * so that we don't get sign warnings at call sites. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: make xfs_dir_cilookup_result use unsigned charDave Chinner
For consistency with the result of the code. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: convert dirnameops to unsigned char namesDave Chinner
To be consistent across the codebase, convert the dirnameops to pass the directory names by unsigned char strings. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: convert DM ops to use unsigned char namesDave Chinner
dmops uses a signed char for it's namespace event. To be consistent with the rest of the code, convert them to unsigned char for the namespace string. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-20xfs: directory names are unsignedDave Chinner
Convert the struct xfs_name to use unsigned chars for the name strings to match both what is stored on disk (__uint8_t) and what the VFS expects (unsigned char). Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-01-15xfs: move more buffer helpers into xfs_buf.cChristoph Hellwig
Move xfsbdstrat and xfs_bdstrat_cb from xfs_lrw.c and xfs_bioerror and xfs_bioerror_relse from xfs_rw.c into xfs_buf.c. This also means xfs_bioerror and xfs_bioerror_relse can be marked static now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-15xfs: clean up xfs_bwriteChristoph Hellwig
Fold XFS_bwrite into it's only caller, xfs_bwrite and move it into xfs_buf.c instead of leaving it as a fairly large inline function. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-15xfs: clean up log buffer writesChristoph Hellwig
Don't bother using XFS_bwrite as it doesn't provide much code for our use case. Instead opencode it and fold xlog_bdstrat_cb into the new xlog_bdstrat helper. Signed-off-by: Christoph Hellwig <hch@lst.de> 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: handle ENOMEM correctly during initialisation of perag structuresDave Chinner
Add proper error handling in case an error occurs while initializing new perag structures for a mount point. The mount structure is restored to its previous state by deleting and freeing any perag structures added during the call. 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: Kill filestreams cache flushDave Chinner
The filestreams cache flush is not needed in the sync code as it does not affect data writeback, and it is now not used by the growfs code, either, so kill it. 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: Add trace points for per-ag refcount debugging.Dave Chinner
Uninline xfs_perag_{get,put} so that tracepoints can be inserted into them to speed debugging of reference count problems. 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: Reference count per-ag structuresDave Chinner
Reference count the per-ag structures to ensure that we keep get/put pairs balanced. Assert that the reference counts are zero at unmount time to catch leaks. In future, reference counts will enable us to safely remove perag structures by allowing us to detect when they are no longer in use. 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: convert remaining direct references to m_peragDave Chinner
Convert the remaining direct lookups of the per ag structures to use get/put accesses. Ensure that the loops across AGs and prior users of the interface balance gets and puts correctly. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>