- 03 Oct, 2016 11 commits
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Darrick J. Wong authored
Create refcount update intent/done log items to record redo information in the log. Because we need to roll transactions between updating the bmbt mapping and updating the reverse mapping, we also have to track the status of the metadata updates that will be recorded in the post-roll transactions, just in case we crash before committing the final transaction. This mechanism enables log recovery to finish what was already started. Signed-off-by:
Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by:
Christoph Hellwig <hch@lst.de>
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Darrick J. Wong authored
Implement the generic btree operations required to manipulate refcount btree blocks. The implementation is similar to the bmapbt, though it will only allocate and free blocks from the AG. Since the refcount root and level fields are separate from the existing roots and levels array, they need a separate logging flag. Signed-off-by:
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Darrick J. Wong authored
Every time we allocate or free a data extent, we might need to split the refcount btree. Reserve some blocks in the transaction to handle this possibility. Even though the deferred refcount code can roll a transaction to avoid overloading the transaction, we can still exceed the reservation. Certain pathological workloads (1k blocks, no cowextsize hint, random directio writes), cause a perfect storm wherein a refcount adjustment of a large range of blocks causes full tree splits in two separate extents in two separate refcount tree blocks; allocating new refcount tree blocks causes rmap btree splits; and all the allocation activity causes the freespace btrees to split, blowing the reservation. (Reproduced by generic/167 over NFS atop XFS) Signed-off-by:
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Darrick J. Wong authored
Modify the growfs code to initialize new refcount btree blocks. Signed-off-by:
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Darrick J. Wong authored
Start constructing the refcount btree implementation by establishing the on-disk format and everything needed to read, write, and manipulate the refcount btree blocks. Signed-off-by:
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Darrick J. Wong authored
Since XFS reserves a small amount of space in each AG as the minimum free space needed for an operation, save some more space in case we touch the refcount btree. Signed-off-by:
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Darrick J. Wong authored
Add new per-AG refcount btree definitions to the per-AG structures. Signed-off-by:
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Darrick J. Wong authored
Define all the tracepoints we need to inspect the refcount btree runtime operation. Signed-off-by:
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Darrick J. Wong authored
If the size of an inline directory is so small that it doesn't even cover the required header size, return an error to userspace instead of ASSERTing and returning 0 like everything's ok. Signed-off-by:
Jan Kara <jack@suse.cz> Reviewed-by:
Brian Foster <bfoster@redhat.com> Reviewed-by:
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Darrick J. Wong authored
Add a new fallocate mode flag that explicitly unshares blocks on filesystems that support such features. The new flag can only be used with an allocate-mode fallocate call. Signed-off-by: -
Darrick J. Wong authored
Introduce XFLAGs for the new XFS CoW extent size hint, and actually plumb the CoW extent size hint into the fsxattr structure. Signed-off-by:
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- 02 Oct, 2016 8 commits
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Dave Chinner authored
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Dave Chinner authored
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Dave Chinner authored
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Dave Chinner authored
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Dave Chinner authored
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Christoph Hellwig authored
After the call to ->direct_IO the final reference to the file might have been dropped by aio_complete already, and the call to file_accessed might cause a use after free. Instead update the access time before the I/O, similar to how we update the time stamps before writes. Signed-off-by:
Dave Chinner <dchinner@redhat.com> Signed-off-by:
Dave Chinner <david@fromorbit.com>
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Christoph Hellwig authored
After the call to __blkdev_direct_IO the final reference to the file might have been dropped by aio_complete already, and the call to file_accessed might cause a use after free. Instead update the access time before the I/O, similar to how we update the time stamps before writes. Signed-off-by:
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Christoph Hellwig authored
For 32-bit architectures we need to cast first_block to u64 before shifting it left. Signed-off-by:
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- 25 Sep, 2016 7 commits
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Brian Foster authored
Log recovery has particular rules around buffer submission along with tricky corner cases where independent transactions can share an LSN. As such, it can be difficult to follow when/why buffers are submitted during recovery. Add a couple tracepoints to post the current LSN of a record when a new record is being processed and when a buffer is being skipped due to LSN ordering. Also, update the recover item class to include the LSN of the current transaction for the item being processed. Signed-off-by:
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Brian Foster authored
Log recovery is currently broken for v5 superblocks in that it never updates the metadata LSN of buffers written out during recovery. The metadata LSN is recorded in various bits of metadata to provide recovery ordering criteria that prevents transient corruption states reported by buffer write verifiers. Without such ordering logic, buffer updates can be replayed out of order and lead to false positive transient corruption states. This is generally not a corruption vector on its own, but corruption detection shuts down the filesystem and ultimately prevents a mount if it occurs during log recovery. This requires an xfs_repair run that clears the log and potentially loses filesystem updates. This problem is avoided in most cases as metadata writes during normal filesystem operation update the metadata LSN appropriately. The problem with log recovery not updating metadata LSNs manifests if the system happens to crash shortly after log recovery itself. In this scenario, it is possible for log recovery to complete all metadata I/O such that the filesystem is consistent. If a crash occurs after that point but before the log tail is pushed forward by subsequent operations, however, the next mount performs the same log recovery over again. If a buffer is updated multiple times in the dirty range of the log, an earlier update in the log might not be valid based on the current state of the associated buffer after all of the updates in the log had been replayed (before the previous crash). If a verifier happens to detect such a problem, the filesystem claims corruption and immediately shuts down. This commonly manifests in practice as directory block verifier failures such as the following, likely due to directory verifiers being particularly detailed in their checks as compared to most others: ... Mounting V5 Filesystem XFS (dm-0): Starting recovery (logdev: internal) XFS (dm-0): Internal error XFS_WANT_CORRUPTED_RETURN at line ... of \ file fs/xfs/libxfs/xfs_dir2_data.c. Caller xfs_dir3_data_verify ... ... Update log recovery to update the metadata LSN of recovered buffers. Since metadata LSNs are already updated by write verifer functions via attached log items, attach a dummy log item to the buffer during validation and explicitly set the LSN of the current transaction. This ensures that the metadata LSN of a buffer is updated based on whether the recovery I/O actually completes, and if so, that subsequent recovery attempts identify that the buffer is already up to date with respect to the current transaction. Signed-off-by: -
Brian Foster authored
The log recovery buffer validation function is invoked in cases where a buffer update may be skipped due to LSN ordering. If the validation function happens to come across directory conversion situations (e.g., a dir3 block to data conversion), it may warn about seeing a buffer log format of one type and a buffer with a magic number of another. This warning is not valid as the buffer update is ultimately skipped. This is indicated by a current_lsn of NULLCOMMITLSN provided by the caller. As such, update xlog_recover_validate_buf_type() to only warn in such cases when a buffer update is expected. Signed-off-by:
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Brian Foster authored
The current LSN must be available to the buffer validation function to provide the ability to update the metadata LSN of the buffer. Pass the current_lsn value down to xlog_recover_validate_buf_type() in preparation. Signed-off-by:
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Brian Foster authored
The fix to log recovery to update the metadata LSN in recovered buffers introduces the requirement that a buffer is submitted only once per current LSN. Log recovery currently submits buffers on transaction boundaries. This is not sufficient as the abstraction between log records and transactions allows for various scenarios where multiple transactions can share the same current LSN. If independent transactions share an LSN and both modify the same buffer, log recovery can incorrectly skip updates and leave the filesystem in an inconsisent state. In preparation for proper metadata LSN updates during log recovery, update log recovery to submit buffers for write on LSN change boundaries rather than transaction boundaries. Explicitly track the current LSN in a new struct xlog field to handle the various corner cases of when the current LSN may or may not change. Signed-off-by:
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Dave Chinner authored
Recently we've had a number of reports where log recovery on a v5 filesystem has reported corruptions that looked to be caused by recovery being re-run over the top of an already-recovered metadata. This has uncovered a bug in recovery (fixed elsewhere) but the vector that caused this was largely unknown. A kdump test started tripping over this problem - the system would be crashed, the kdump kernel and environment would boot and dump the kernel core image, and then the system would reboot. After reboot, the root filesystem was triggering log recovery and corruptions were being detected. The metadumps indicated the above log recovery issue. What is happening is that the kdump kernel and environment is mounting the root device read-only to find the binaries needed to do it's work. The result of this is that it is running log recovery. However, because there were unlinked files and EFIs to be processed by recovery, the completion of phase 1 of log recovery could not mark the log clean. And because it's a read-only mount, the unmount process does not write records to the log to mark it clean, either. Hence on the next mount of the filesystem, log recovery was run again across all the metadata that had already been recovered and this is what triggered corruption warnings. To avoid this problem, we need to ensure that a read-only mount always updates the log when it completes the second phase of recovery. We already handle this sort of issue with rw->ro remount transitions, so the solution is as simple as quiescing the filesystem at the appropriate time during the mount process. This results in the log being marked clean so the mount behaviour recorded in the logs on repeated RO mounts will change (i.e. log recovery will no longer be run on every mount until a RW mount is done). This is a user visible change in behaviour, but it is harmless. Signed-off-by:
Eric Sandeen <sandeen@redhat.com> Signed-off-by:
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Dave Chinner authored
When adding a new remote attribute, we write the attribute to the new extent before the allocation transaction is committed. This means we cannot reuse busy extents as that violates crash consistency semantics. Hence we currently treat remote attribute extent allocation like userdata because it has the same overwrite ordering constraints as userdata. Unfortunately, this also allows the allocator to incorrectly apply extent size hints to the remote attribute extent allocation. This results in interesting failures, such as transaction block reservation overruns and in-memory inode attribute fork corruption. To fix this, we need to separate the busy extent reuse configuration from the userdata configuration. This changes the definition of XFS_BMAPI_METADATA slightly - it now means that allocation is metadata and reuse of busy extents is acceptible due to the metadata ordering semantics of the journal. If this flag is not set, it means the allocation is that has unordered data writeback, and hence busy extent reuse is not allowed. It no longer implies the allocation is for user data, just that the data write will not be strictly ordered. This matches the semantics for both user data and remote attribute block allocation. As such, This patch changes the "userdata" field to a "datatype" field, and adds a "no busy reuse" flag to the field. When we detect an unordered data extent allocation, we immediately set the no reuse flag. We then set the "user data" flags based on the inode fork we are allocating the extent to. Hence we only set userdata flags on data fork allocations now and consider attribute fork remote extents to be an unordered metadata extent. The result is that remote attribute extents now have the expected allocation semantics, and the data fork allocation behaviour is completely unchanged. It should be noted that there may be other ways to fix this (e.g. use ordered metadata buffers for the remote attribute extent data write) but they are more invasive and difficult to validate both from a design and implementation POV. Hence this patch takes the simple, obvious route to fixing the problem... Reported-and-tested-by:
Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by:
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- 19 Sep, 2016 14 commits
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Christoph Hellwig authored
Signed-off-by:
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Christoph Hellwig authored
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Christoph Hellwig authored
Another users of buffer_heads bytes the dust. Signed-off-by:
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Christoph Hellwig authored
Rename the current function to __xfs_setfilesize and add a non-static wrapper that also takes care of creating the transaction. This new helper will be used by the new iomap-based DAX path. Signed-off-by:
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Christoph Hellwig authored
We always just read the extent first, and will later lock exlusively after first dropping the lock in case we actually allocate blocks. Signed-off-by:
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Christoph Hellwig authored
So far DAX writes inherited the locking from direct I/O writes, but the direct I/O model of using shared locks for writes is actually wrong for DAX. For direct I/O we're out of any standards and don't have to provide the Posix required exclusion between writers, but for DAX which gets transparently enable on applications without any knowledge of it we can't simply drop the requirement. Even worse this only happens for aligned writes and thus doesn't show up for many typical use cases. Signed-off-by:
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Christoph Hellwig authored
Very similar to the existing dax_fault function, but instead of using the get_block callback we rely on the iomap_ops vector from iomap.c. That also avoids having to do two calls into the file system for write faults. Signed-off-by:
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Christoph Hellwig authored
This is a much simpler implementation of the DAX read/write path that makes use of the iomap infrastructure. It does not try to mirror the direct I/O calling conventions and thus doesn't have to deal with i_dio_count or the end_io handler, but instead leaves locking and filesystem-specific I/O completion to the caller. Signed-off-by:
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Christoph Hellwig authored
This way we can use this helper for the iomap based DAX implementation as well. Signed-off-by:
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Christoph Hellwig authored
This way we can use this helper for the iomap based DAX implementation as well. Signed-off-by:
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Christoph Hellwig authored
This allows the DAX code to use it. Signed-off-by:
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Christoph Hellwig authored
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Christoph Hellwig authored
Currently xfs_iomap_write_delay does up to lookups in the inode extent tree, which is rather costly especially with the new iomap based write path and small write sizes. But it turns out that the low-level xfs_bmap_search_extents gives us all the information we need in the regular delalloc buffered write path: - it will return us an extent covering the block we are looking up if it exists. In that case we can simply return that extent to the caller and are done - it will tell us if we are beyoned the last current allocated block with an eof return parameter. In that case we can create a delalloc reservation and use the also returned information about the last extent in the file as the hint to size our delalloc reservation. - it can tell us that we are writing into a hole, but that there is an extent beyoned this hole. In this case we can create a delalloc reservation that covers the requested size (possible capped to the next existing allocation). All that can be done in one single routine instead of bouncing up and down a few layers. This reduced the CPU overhead of the block mapping routines and also simplified the code a lot. Signed-off-by:
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Christoph Hellwig authored
For long growing file writes we will usually already have the eofblocks tag set when adding more speculative preallocations. Add a flag in the inode to allow us to skip the the fairly expensive AG-wide spinlocks and multiple radix tree operations in that case. Signed-off-by:
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