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path: root/fs/xfs/xfs_buf.h
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2017-09-20xfs: push buffer of flush locked dquot to avoid quotacheck deadlockBrian Foster
commit 7912e7fef2aebe577f0b46d3cba261f2783c5695 upstream. Reclaim during quotacheck can lead to deadlocks on the dquot flush lock: - Quotacheck populates a local delwri queue with the physical dquot buffers. - Quotacheck performs the xfs_qm_dqusage_adjust() bulkstat and dirties all of the dquots. - Reclaim kicks in and attempts to flush a dquot whose buffer is already queud on the quotacheck queue. The flush succeeds but queueing to the reclaim delwri queue fails as the backing buffer is already queued. The flush unlock is now deferred to I/O completion of the buffer from the quotacheck queue. - The dqadjust bulkstat continues and dirties the recently flushed dquot once again. - Quotacheck proceeds to the xfs_qm_flush_one() walk which requires the flush lock to update the backing buffers with the in-core recalculated values. It deadlocks on the redirtied dquot as the flush lock was already acquired by reclaim, but the buffer resides on the local delwri queue which isn't submitted until the end of quotacheck. This is reproduced by running quotacheck on a filesystem with a couple million inodes in low memory (512MB-1GB) situations. This is a regression as of commit 43ff2122e6 ("xfs: on-stack delayed write buffer lists"), which removed a trylock and buffer I/O submission from the quotacheck dquot flush sequence. Quotacheck first resets and collects the physical dquot buffers in a delwri queue. Then, it traverses the filesystem inodes via bulkstat, updates the in-core dquots, flushes the corrected dquots to the backing buffers and finally submits the delwri queue for I/O. Since the backing buffers are queued across the entire quotacheck operation, dquot reclaim cannot possibly complete a dquot flush before quotacheck completes. Therefore, quotacheck must submit the buffer for I/O in order to cycle the flush lock and flush the dirty in-core dquot to the buffer. Add a delwri queue buffer push mechanism to submit an individual buffer for I/O without losing the delwri queue status and use it from quotacheck to avoid the deadlock. This restores quotacheck behavior to as before the regression was introduced. Reported-by: Martin Svec <martin.svec@zoner.cz> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-07xfs: fix up quotacheck buffer list error handlingBrian Foster
commit 20e8a063786050083fe05b4f45be338c60b49126 upstream. The quotacheck error handling of the delwri buffer list assumes the resident buffers are locked and doesn't clear the _XBF_DELWRI_Q flag on the buffers that are dequeued. This can lead to assert failures on buffer release and possibly other locking problems. Move this code to a delwri queue cancel helper function to encapsulate the logic required to properly release buffers from a delwri queue. Update the helper to clear the delwri queue flag and call it from quotacheck. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-07xfs: use ->b_state to fix buffer I/O accounting release raceBrian Foster
commit 63db7c815bc0997c29e484d2409684fdd9fcd93b upstream. We've had user reports of unmount hangs in xfs_wait_buftarg() that analysis shows is due to btp->bt_io_count == -1. bt_io_count represents the count of in-flight asynchronous buffers and thus should always be >= 0. xfs_wait_buftarg() waits for this value to stabilize to zero in order to ensure that all untracked (with respect to the lru) buffers have completed I/O processing before unmount proceeds to tear down in-core data structures. The value of -1 implies an I/O accounting decrement race. Indeed, the fact that xfs_buf_ioacct_dec() is called from xfs_buf_rele() (where the buffer lock is no longer held) means that bp->b_flags can be updated from an unsafe context. While a user-level reproducer is currently not available, some intrusive hacks to run racing buffer lookups/ioacct/releases from multiple threads was used to successfully manufacture this problem. Existing callers do not expect to acquire the buffer lock from xfs_buf_rele(). Therefore, we can not safely update ->b_flags from this context. It turns out that we already have separate buffer state bits and associated serialization for dealing with buffer LRU state in the form of ->b_state and ->b_lock. Therefore, replace the _XBF_IN_FLIGHT flag with a ->b_state variant, update the I/O accounting wrappers appropriately and make sure they are used with the correct locking. This ensures that buffer in-flight state can be modified at buffer release time without racing with modifications from a buffer lock holder. Fixes: 9c7504aa72b6 ("xfs: track and serialize in-flight async buffers against unmount") Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Libor Pechacek <lpechacek@suse.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-07-20xfs: track and serialize in-flight async buffers against unmountBrian Foster
Newly allocated XFS metadata buffers are added to the LRU once the hold count is released, which typically occurs after I/O completion. There is no other mechanism at current that tracks the existence or I/O state of a new buffer. Further, readahead I/O tends to be submitted asynchronously by nature, which means the I/O can remain in flight and actually complete long after the calling context is gone. This means that file descriptors or any other holds on the filesystem can be released, allowing the filesystem to be unmounted while I/O is still in flight. When I/O completion occurs, core data structures may have been freed, causing completion to run into invalid memory accesses and likely to panic. This problem is reproduced on XFS via directory readahead. A filesystem is mounted, a directory is opened/closed and the filesystem immediately unmounted. The open/close cycle triggers a directory readahead that if delayed long enough, runs buffer I/O completion after the unmount has completed. To address this problem, add a mechanism to track all in-flight, asynchronous buffers using per-cpu counters in the buftarg. The buffer is accounted on the first I/O submission after the current reference is acquired and unaccounted once the buffer is returned to the LRU or freed. Update xfs_wait_buftarg() to wait on all in-flight I/O before walking the LRU list. Once in-flight I/O has completed and the workqueue has drained, all new buffers should have been released onto the LRU. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-07-20xfs: exclude never-released buffers from buftarg I/O accountingBrian Foster
The upcoming buftarg I/O accounting mechanism maintains a count of all buffers that have undergone I/O in the current hold-release cycle. Certain buffers associated with core infrastructure (e.g., the xfs_mount superblock buffer, log buffers) are never released, however. This means that accounting I/O submission on such buffers elevates the buftarg count indefinitely and could lead to lockup on unmount. Define a new buffer flag to explicitly exclude buffers from buftarg I/O accounting. Set the flag on the superblock and associated log buffers. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-05-18xfs: add configuration of error failure speedCarlos Maiolino
On reception of an error, we can fail immediately, perform some bound amount of retries or retry indefinitely. The current behaviour we have is to retry forever. However, we'd like the ability to choose how long the filesystem should try after an error, it can either fail immediately, retry a few times, or retry forever. This is implemented by using max_retries sysfs attribute, to hold the amount of times we allow the filesystem to retry after an error. Being -1 a special case where the filesystem will retry indefinitely. Add both a maximum retry count and a retry timeout so that we can bound by time and/or physical IO attempts. Finally, plumb these into xfs_buf_iodone error processing so that the error behaviour follows the selected configuration. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-05-18xfs: add configurable error support to metadata buffersCarlos Maiolino
With the error configuration handle for async metadata write errors in place, we can now add initial support to the IO error processing in xfs_buf_iodone_error(). Add an infrastructure function to look up the configuration handle, and rearrange the error handling to prepare the way for different error handling conigurations to be used. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-10xfs: remove XFS_BUF_ZEROFLAGS macroDave Chinner
The places where we use this macro already clear unnecessary IO flags (e.g. through xfs_bwrite()) or never have unexpected IO flags set on them in the first place (e.g. iclog buffers). Remove the macro from these locations, and where necessary clear only the specific flags that are conditional in the current buffer context. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-10xfs: remove XBF_STALE flag wrapper macrosDave Chinner
They only set/clear/check a flag, no need for obfuscating this with a macro. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-10xfs: remove XBF_WRITE flag wrapper macrosDave Chinner
They only set/clear/check a flag, no need for obfuscating this with a macro. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-10xfs: remove XBF_READ flag wrapper macrosDave Chinner
They only set/clear/check a flag, no need for obfuscating this with a macro. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-10xfs: remove XBF_ASYNC flag wrapper macrosDave Chinner
They only set/clear/check a flag, no need for obfuscating this with a macro. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-02-10xfs: remove XBF_DONE flag wrapper macrosDave Chinner
They only set/clear/check a flag, no need for obfuscating this with a macro. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04xfs: print name of verifier if it failsEric Sandeen
This adds a name to each buf_ops structure, so that if a verifier fails we can print the type of verifier that failed it. Should be a slight debugging aid, I hope. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-09-08dax: move DAX-related functions to a new headerMatthew Wilcox
In order to handle the !CONFIG_TRANSPARENT_HUGEPAGES case, we need to return VM_FAULT_FALLBACK from the inlined dax_pmd_fault(), which is defined in linux/mm.h. Given that we don't want to include <linux/mm.h> in <linux/fs.h>, the easiest solution is to move the DAX-related functions to a new header, <linux/dax.h>. We could also have moved VM_FAULT_* definitions to a new header, or a different header that isn't quite such a boil-the-ocean header as <linux/mm.h>, but this felt like the best option. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-21xfs: return a void pointer from xfs_buf_offsetChristoph Hellwig
This avoids all kinds of unessecary casts in an envrionment like Linux where we can assume that pointer arithmetics are support on void pointers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-12-03xfs: split metadata and log buffer completion to separate workqueuesBrian Foster
XFS traditionally sends all buffer I/O completion work to a single workqueue. This includes metadata buffer completion and log buffer completion. The log buffer completion requires a high priority queue to prevent stalls due to log forces getting stuck behind other queued work. Rather than continue to prioritize all buffer I/O completion due to the needs of log completion, split log buffer completion off to m_log_workqueue and move the high priority flag from m_buf_workqueue to m_log_workqueue. Add a b_ioend_wq wq pointer to xfs_buf to allow completion workqueue customization on a per-buffer basis. Initialize b_ioend_wq to m_buf_workqueue by default in the generic buffer I/O submission path. Finally, override the default wq with the high priority m_log_workqueue in the log buffer I/O submission path. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-10-01xfs: check xfs_buf_read_uncached returns correctlyDave Chinner
xfs_buf_read_uncached() has two failure modes. If can either return NULL or bp->b_error != 0 depending on the type of failure, and not all callers check for both. Fix it so that xfs_buf_read_uncached() always returns the error status, and the buffer is returned as a function parameter. The buffer will only be returned on success. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-10-01xfs: introduce xfs_buf_submit[_wait]Dave Chinner
There is a lot of cookie-cutter code that looks like: if (shutdown) handle buffer error xfs_buf_iorequest(bp) error = xfs_buf_iowait(bp) if (error) handle buffer error spread through XFS. There's significant complexity now in xfs_buf_iorequest() to specifically handle this sort of synchronous IO pattern, but there's all sorts of nasty surprises in different error handling code dependent on who owns the buffer references and the locks. Pull this pattern into a single helper, where we can hide all the synchronous IO warts and hence make the error handling for all the callers much saner. This removes the need for a special extra reference to protect IO completion processing, as we can now hold a single reference across dispatch and waiting, simplifying the sync IO smeantics and error handling. In doing this, also rename xfs_buf_iorequest to xfs_buf_submit and make it explicitly handle on asynchronous IO. This forces all users to be switched specifically to one interface or the other and removes any ambiguity between how the interfaces are to be used. It also means that xfs_buf_iowait() goes away. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-10-01xfs: kill xfs_bioerror_relseDave Chinner
There is only one caller now - xfs_trans_read_buf_map() - and it has very well defined call semantics - read, synchronous, and b_iodone is NULL. Hence it's pretty clear what error handling is necessary for this case. The bigger problem of untangling xfs_trans_read_buf_map error handling is left to a future patch. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-10-01xfs: rework xfs_buf_bio_endio error handlingDave Chinner
Currently the report of a bio error from completion immediately marks the buffer with an error. The issue is that this is racy w.r.t. synchronous IO - the submitter can see b_error being set before the IO is complete, and hence we cannot differentiate between submission failures and completion failures. Add an internal b_io_error field protected by the b_lock to catch IO completion errors, and only propagate that to the buffer during final IO completion handling. Hence we can tell in xfs_buf_iorequest if we've had a submission failure bey checking bp->b_error before dropping our b_io_remaining reference - that reference will prevent b_io_error values from being propagated to b_error in the event that completion races with submission. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-10-01xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionalityDave Chinner
We do some work in xfs_buf_ioend, and some work in xfs_buf_iodone_work, but much of that functionality is the same. This work can all be done in a single function, leaving xfs_buf_iodone just a wrapper to determine if we should execute it by workqueue or directly. hence rename xfs_buf_iodone_work to xfs_buf_ioend(), and add a new xfs_buf_ioend_async() for places that need async processing. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-06-25xfs: global error sign conversionDave Chinner
Convert all the errors the core XFs code to negative error signs like the rest of the kernel and remove all the sign conversion we do in the interface layers. Errors for conversion (and comparison) found via searches like: $ git grep " E" fs/xfs $ git grep "return E" fs/xfs $ git grep " E[A-Z].*;$" fs/xfs Negation points found via searches like: $ git grep "= -[a-z,A-Z]" fs/xfs $ git grep "return -[a-z,A-D,F-Z]" fs/xfs $ git grep " -[a-z].*;" fs/xfs [ with some bits I missed from Brian Foster ] Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-06-09Merge branch 'xfs-misc-fixes-3-for-3.16' into for-nextDave Chinner
2014-06-06xfs: kill xfs_buf_geterror()Dave Chinner
Most of the callers are just calling ASSERT(!xfs_buf_geterror()) which means they are checking for bp->b_error == 0. If bp is null in this case, we will assert fail, and hence it's no different in result to oopsing because of a null bp. In some cases, errors have already been checked for or the function returning the buffer can't return a buffer with an error, so it's just a redundant assert. Either way, the assert can either be removed. The other two non-assert callers can just test for a buffer and error properly. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-04-14xfs: remove unused args from xfs_alloc_buftarg()Eric Sandeen
Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-04-14xfs: remove unused blocksize arg from xfs_setsize_buftarg()Eric Sandeen
Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27xfs: add helper for updating checksums on xfs_bufsEric Sandeen
Many/most callers of xfs_update_cksum() pass bp->b_addr and BBTOB(bp->b_length) as the first 2 args. Add a helper which can just accept the bp and the crc offset, and work it out on its own, for brevity. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27xfs: add helper for verifying checksums on xfs_bufsEric Sandeen
Many/most callers of xfs_verify_cksum() pass bp->b_addr and BBTOB(bp->b_length) as the first 2 args. Add a helper which can just accept the bp and the crc offset, and work it out on its own, for brevity. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-01-24xfs: allow logical-sector sized O_DIRECTEric Sandeen
Some time ago, mkfs.xfs started picking the storage physical sector size as the default filesystem "sector size" in order to avoid RMW costs incurred by doing IOs at logical sector size alignments. However, this means that for a filesystem made with i.e. a 4k sector size on an "advanced format" 4k/512 disk, 512-byte direct IOs are no longer allowed. This means that XFS has essentially turned this AF drive into a hard 4K device, from the filesystem on up. XFS's mkfs-specified "sector size" is really just controlling the minimum size & alignment of filesystem metadata. There is no real need to tightly couple XFS's minimal metadata size to the minimum allowed direct IO size; XFS can continue doing metadata in optimal sizes, but still allow smaller DIOs for apps which issue them, for whatever reason. This patch adds a new field to the xfs_buftarg, so that we now track 2 sizes: 1) The metadata sector size, which is the minimum unit and alignment of IO which will be performed by metadata operations. 2) The device logical sector size The first is used internally by the file system for metadata alignment and IOs. The second is used for the minimum allowed direct IO alignment. This has passed xfstests on filesystems made with 4k sectors, including when run under the patch I sent to ignore XFS_IOC_DIOINFO, and issue 512 DIOs anyway. I also directly tested end of block behavior on preallocated, sparse, and existing files when we do a 512 IO into a 4k file on a 4k-sector filesystem, to be sure there were no unexpected behaviors. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2014-01-24xfs: rename xfs_buftarg structure membersEric Sandeen
In preparation for adding new members to the structure, give these old ones more descriptive names: bt_ssize -> bt_meta_sectorsize bt_smask -> bt_meta_sectormask Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2014-01-24xfs: clean up xfs_buftargEric Sandeen
Clean up the xfs_buftarg structure a bit: - remove bt_bsize which is never used - replace bt_sshift with bt_ssize; we only ever shift it back Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-12-17xfs: abort metadata writeback on permanent errorsDave Chinner
If we are doing aysnc writeback of metadata, we can get write errors but have nobody to report them to. At the moment, we simply attempt to reissue the write from io completion in the hope that it's a transient error. When it's not a transient error, the buffer is stuck forever in this loop, and we cannot break out of it. Eventually, unmount will hang because the AIL cannot be emptied and everything goes downhill from them. To solve this problem, only retry the write IO once before aborting it. We don't throw the buffer away because some transient errors can last minutes (e.g. FC path failover) or even hours (thin provisioned devices that have run out of backing space) before they go away. Hence we really want to keep trying until we can't try any more. Because the buffer was not cleaned, however, it does not get removed from the AIL and hence the next pass across the AIL will start IO on it again. As such, we still get the "retry forever" semantics that we currently have, but we allow other access to the buffer in the mean time. Meanwhile the filesystem can continue to modify the buffer and relog it, so the IO errors won't hang the log or the filesystem. Now when we are pushing the AIL, we can see all these "permanent IO error" buffers and we can issue a warning about failures before we retry the IO. We can also catch these buffers when unmounting an issue a corruption warning, too. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-12-17xfs: remove xfsbdstrat errorChristoph Hellwig
The xfsbdstrat helper is a small but useless wrapper for xfs_buf_iorequest that handles the case of a shut down filesystem. Most of the users have private, uncached buffers that can just be freed in this case, but the complex error handling in xfs_bioerror_relse messes up the case when it's called without a locked buffer. Remove xfsbdstrat and opencode the error handling in the callers. All but one can simply return an error and don't need to deal with buffer state, and the one caller that cares about the buffer state could do with a major cleanup as well, but we'll defer that to later. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-09-10xfs: rework buffer dispose list trackingDave Chinner
In converting the buffer lru lists to use the generic code, the locking for marking the buffers as on the dispose list was lost. This results in confusion in LRU buffer tracking and acocunting, resulting in reference counts being mucked up and filesystem beig unmountable. To fix this, introduce an internal buffer spinlock to protect the state field that holds the dispose list information. Because there is now locking needed around xfs_buf_lru_add/del, and they are used in exactly one place each two lines apart, get rid of the wrappers and code the logic directly in place. Further, the LRU emptying code used on unmount is less than optimal. Convert it to use a dispose list as per a normal shrinker walk, and repeat the walk that fills the dispose list until the LRU is empty. Thi avoids needing to drop and regain the LRU lock for every item being freed, and allows the same logic as the shrinker isolate call to be used. Simpler, easier to understand. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-10xfs: convert buftarg LRU to generic codeDave Chinner
Convert the buftarg LRU to use the new generic LRU list and take advantage of the functionality it supplies to make the buffer cache shrinker node aware. Signed-off-by: Glauber Costa <glommer@openvz.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-01-16xfs: use b_maps[] for discontiguous buffersMark Tinguely
Commits starting at 77c1a08 introduced a multiple segment support to xfs_buf. xfs_trans_buf_item_match() could not find a multi-segment buffer in the transaction because it was looking at the single segment block number rather than the multi-segment b_maps[0].bm.bn. This results on a recursive buffer lock that can never be satisfied. This patch: 1) Changed the remaining b_map accesses to be b_maps[0] accesses. 2) Renames the single segment b_map structure to __b_map to avoid future confusion. Signed-off-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
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: add buffer pre-write callbackDave Chinner
Add a callback to the buffer write path to enable verification of the buffer and CRC calculation prior to issuing the write to the underlying storage. If the callback function detects some kind of failure or error condition, it must mark the buffer with an error so that the caller can take appropriate action. In the case of xfs_buf_ioapply(), a corrupt metadta buffer willt rigger a shutdown of the filesystem, because something is clearly wrong and we can't allow corrupt metadata to be written to disk. 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: 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>
2012-08-29xfs: fix race while discarding buffers [V4]Carlos Maiolino
While xfs_buftarg_shrink() is freeing buffers from the dispose list (filled with buffers from lru list), there is a possibility to have xfs_buf_stale() racing with it, and removing buffers from dispose list before xfs_buftarg_shrink() does it. This happens because xfs_buftarg_shrink() handle the dispose list without locking and the test condition in xfs_buf_stale() checks for the buffer being in *any* list: if (!list_empty(&bp->b_lru)) If the buffer happens to be on dispose list, this causes the buffer counter of lru list (btp->bt_lru_nr) to be decremented twice (once in xfs_buftarg_shrink() and another in xfs_buf_stale()) causing a wrong account usage of the lru list. This may cause xfs_buftarg_shrink() to return a wrong value to the memory shrinker shrink_slab(), and such account error may also cause an underflowed value to be returned; since the counter is lower than the current number of items in the lru list, a decrement may happen when the counter is 0, causing an underflow on the counter. The fix uses a new flag field (and a new buffer flag) to serialize buffer handling during the shrink process. The new flag field has been designed to use btp->bt_lru_lock/unlock instead of xfs_buf_lock/unlock mechanism. dchinner, sandeen, aquini and aris also deserve credits for this. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-13xfs: do not call xfs_bdstrat_cb in xfs_buf_iodone_callbacksChristoph Hellwig
xfs_bdstrat_cb only adds a check for a shutdown filesystem over xfs_buf_iorequest, but xfs_buf_iodone_callbacks just checked for a shut down filesystem a little earlier. In addition the shutdown handling in xfs_bdstrat_cb is not very suitable for this caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-01xfs: add discontiguous buffer map interfaceDave Chinner
With the internal interfaces supporting discontiguous buffer maps, add external lookup, read and get interfaces so they can start to be used. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-01xfs: convert internal buffer functions to pass mapsDave Chinner
While the external interface currently uses separate blockno/length variables, we need to move internal interfaces to passing and parsing vector maps. This will then allow us to add external interfaces to support discontiguous buffer maps as the internal code will already support them. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-01xfs: separate buffer indexing from block mapDave Chinner
To support discontiguous buffers in the buffer cache, we need to separate the cache index variables from the I/O map. While this is currently a 1:1 mapping, discontiguous buffer support will break this relationship. However, for caching purposes, we can still treat them the same as a contiguous buffer - the block number of the first block and the length of the buffer - as that is still a unique representation. Also, the only way we will ever access the discontiguous regions of buffers is via bulding the complete buffer in the first place, so using the initial block number and entire buffer length is a sane way to index the buffers. Add a block mapping vector construct to the xfs_buf and use it in the places where we are doing IO instead of the current b_bn/b_length variables. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14xfs: make XBF_MAPPED the default behaviourDave Chinner
Rather than specifying XBF_MAPPED for almost all buffers, introduce XBF_UNMAPPED for the couple of users that use unmapped buffers. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14xfs: kill XBF_DONTBLOCKDave Chinner
Just about all callers of xfs_buf_read() and xfs_buf_get() use XBF_DONTBLOCK. This is used to make memory allocation use GFP_NOFS rather than GFP_KERNEL to avoid recursion through memory reclaim back into the filesystem. All the blocking get calls in growfs occur inside a transaction, even though they are no part of the transaction, so all allocation will be GFP_NOFS due to the task flag PF_TRANS being set. The blocking read calls occur during log recovery, so they will probably be unaffected by converting to GFP_NOFS allocations. Hence make XBF_DONTBLOCK behaviour always occur for buffers and kill the flag. 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: kill XBF_LOCKDave Chinner
Buffers are always returned locked from the lookup routines. Hence we don't need to tell the lookup routines to return locked buffers, on to try and lock them. Remove XBF_LOCK from all the callers and from internal buffer cache usage. 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: kill xfs_buf_btocDave Chinner
xfs_buf_btoc and friends are simple macros that do basic block to page index conversion and vice versa. These aren't widely used, and we use open coded masking and shifting everywhere else. Hence remove the macros and open code the work they do. Also, use of PAGE_CACHE_{SIZE|SHIFT|MASK} for these macros is now incorrect - we are using pages directly and not the page cache, so use PAGE_{SIZE|MASK|SHIFT} instead. 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: use blocks for storing the desired IO sizeDave Chinner
Now that we pass block counts everywhere, and index buffers by block number and length in units of blocks, convert the desired IO size into block counts rather than bytes. Convert the code to use block counts, and those that need byte counts get converted at the time of use. Rename the b_desired_count variable to something closer to it's purpose - b_io_length - as it is only used to specify the length of an IO for a subset of the buffer. The only time this is used is for log IO - both writing iclogs and during log recovery. In all other cases, the b_io_length matches b_length, and hence a lot of code confuses the two. e.g. the buf item code uses the io count exclusively when it should be using the buffer length. Fix these apprpriately as they are found. Also, remove the XFS_BUF_{SET_}COUNT() macros that are just wrappers around the desired IO length. They only serve to make the code shouty loud, don't actually add any real value, and are often used incorrectly. 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>