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* xfs: fix direct IO nested transaction deadlock.Dave Chinner2012-11-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The direct IO path can do a nested transaction reservation when writing past the EOF. The first transaction is the append transaction for setting the filesize at IO completion, but we can also need a transaction for allocation of blocks. If the log is low on space due to reservations and small log, the append transaction can be granted after wating for space as the only active transaction in the system. This then attempts a reservation for an allocation, which there isn't space in the log for, and the reservation sleeps. The result is that there is nothing left in the system to wake up all the processes waiting for log space to come free. The stack trace that shows this deadlock is relatively innocuous: xlog_grant_head_wait xlog_grant_head_check xfs_log_reserve xfs_trans_reserve xfs_iomap_write_direct __xfs_get_blocks xfs_get_blocks_direct do_blockdev_direct_IO __blockdev_direct_IO xfs_vm_direct_IO generic_file_direct_write xfs_file_dio_aio_writ xfs_file_aio_write do_sync_write vfs_write This was discovered on a filesystem with a log of only 10MB, and a log stripe unit of 256k whih increased the base reservations by 512k. Hence a allocation transaction requires 1.2MB of log space to be available instead of only 260k, and so greatly increased the chance that there wouldn't be enough log space available for the nested transaction to succeed. The key to reproducing it is this mkfs command: mkfs.xfs -f -d agcount=16,su=256k,sw=12 -l su=256k,size=2560b $SCRATCH_DEV The test case was a 1000 fsstress processes running with random freeze and unfreezes every few seconds. Thanks to Eryu Guan (eguan@redhat.com) for writing the test that found this on a system with a somewhat unique default configuration.... cc: <stable@vger.kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andrew Dahl <adahl@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: byte range granularity for XFS_IOC_ZERO_RANGEDave Chinner2012-11-29
| | | | | | | | | | | | | XFS_IOC_ZERO_RANGE simply does not work properly for non page cache aligned ranges. Neither test 242 or 290 exercise this correctly, so the behaviour is completely busted even though the tests pass. Fix it to support full byte range granularity as was originally intended for this ioctl. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: inode allocation should use unmapped buffers.Dave Chinner2012-11-26
| | | | | | | | | | | | | | Inode buffers do not need to be mapped as inodes are read or written directly from/to the pages underlying the buffer. This fixes a regression introduced by commit 611c994 ("xfs: make XBF_MAPPED the default behaviour"). 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: Dave Chinner <david@fromorbit.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add CRC checks to the logChristoph Hellwig2012-11-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement CRCs for the log buffers. We re-use a field in struct xlog_rec_header that was used for a weak checksum of the log buffer payload in debug builds before. The new checksumming uses the crc32c checksum we will use elsewhere in XFS, and also protects the record header and addition cycle data. Due to this there are some interesting changes in xlog_sync, as we need to do the cycle wrapping for the split buffer case much earlier, as we would touch the buffer after generating the checksum otherwise. The CRC calculation is always enabled, even for non-CRC filesystems, as adding this CRC does not change the log format. On non-CRC filesystems, only issue an alert if a CRC mismatch is found and allow recovery to continue - this will act as an indicator that log recovery problems are a result of log corruption. On CRC enabled filesystems, however, log recovery will fail. Note that existing debug kernels will write a simple checksum value to the log, so the first time this is run on a filesystem taht was last used on a debug kernel it will through CRC mismatch warning errors. These can be ignored. Initially based on a patch from Dave Chinner, then modified significantly by Christoph Hellwig. Modified again by Dave Chinner to get to this version. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add CRC infrastructureChristoph Hellwig2012-11-19
| | | | | | | | | | | | | | | - add a mount feature bit for CRC enabled filesystems - add some helpers for generating and verifying the CRCs - add a copy_uuid helper The checksumming helpers are loosely based on similar ones in sctp, all other bits come from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: convert buffer verifiers to an ops structure.Dave Chinner2012-11-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* xfs: connect up write verifiers to new buffersDave Chinner2012-11-15
| | | | | | | | | | Metadata buffers that are read from disk have write verifiers already attached to them, but newly allocated buffers do not. Add appropriate write verifiers to all new metadata buffers. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add pre-write metadata buffer verifier callbacksDave Chinner2012-11-15
| | | | | | | | | | | | | | | | | | | | | These verifiers are essentially the same code as the read verifiers, but do not require ioend processing. Hence factor the read verifier functions and add a new write verifier wrapper that is used as the callback. This is done as one large patch for all verifiers rather than one patch per verifier as the change is largely mechanical. This includes hooking up the write verifier via the read verifier function. Hooking up the write verifier for buffers obtained via xfs_trans_get_buf() will be done in a separate patch as that touches code in many different places rather than just the verifier functions. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add buffer pre-write callbackDave Chinner2012-11-15
| | | | | | | | | | | | | | | | | 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>
* xfs: Add verifiers to dir2 data readahead.Dave Chinner2012-11-15
| | | | | | Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add xfs_da_node verificationDave Chinner2012-11-15
| | | | | | Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: factor and verify attr leaf readsDave Chinner2012-11-15
| | | | | | | | | | | Some reads are not converted yet because it isn't obvious ahead of time what the format of the block is going to be. Need to determine how to tell if the first block in the tree is a node or leaf format block. That will be done in later patches. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: factor dir2 leaf readDave Chinner2012-11-15
| | | | | | Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: factor out dir2 data block readingDave Chinner2012-11-15
| | | | | | | | And add a verifier callback function while there. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: factor dir2 free block readingDave Chinner2012-11-15
| | | | | | | | | Also factor out the updating of the free block when removing entries from leaf blocks, and add a verifier callback for reads. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: verify dir2 block format buffersDave Chinner2012-11-15
| | | | | | | | | | | | | Add a dir2 block format read verifier. To fully verify every block when read, call xfs_dir2_data_check() on them. Change xfs_dir2_data_check() to do runtime checking, convert ASSERT() checks to XFS_WANT_CORRUPTED_RETURN(), which will trigger an ASSERT failure on debug kernels, but on production kernels will dump an error to dmesg and return EFSCORRUPTED to the caller. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: factor dir2 block read operationsDave Chinner2012-11-15
| | | | | | | | | | | In preparation for verifying dir2 block format buffers, factor the read operations out of the block operations (lookup, addname, getdents) and some of the additional logic to make it easier to understand an dmodify the code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add verifier callback to directory read codeDave Chinner2012-11-15
| | | | | | | 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>
* xfs: verify dquot blocks as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | | | | | Add a dquot buffer verify callback function and pass it into the buffer read functions. This checks all the dquots in a buffer, but cannot completely verify the dquot ids are correct. Also, errors cannot be repaired, so an additional function is added to repair bad dquots in the buffer if such an error is detected in a context where repair is allowed. 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>
* xfs: verify btree blocks as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | | | | | | Add an btree block verify callback function and pass it into the buffer read functions. Because each different btree block type requires different verification, add a function to the ops structure that is called from the generic code. Also, propagate the verification callback functions through the readahead functions, and into the external bmap and bulkstat inode readahead code that uses the generic btree buffer read functions. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: verify inode buffers as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | | | | Add an inode buffer verify callback function and pass it into the buffer read functions. Inodes are special in that the verbose checks will be done when reading the inode, but we still need to sanity check the buffer when that is first read. Always verify the magic numbers in all inodes in the buffer, rather than jus ton debug kernels. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: verify AGFL blocks as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | | | | | | | Add an AGFL block verify callback function and pass it into the buffer read functions. While this commit adds verification code to the AGFL, it cannot be used reliably until the CRC format change comes along as mkfs does not initialise the full AGFL. Hence it can be full of garbage at the first mount and will fail verification right now. CRC enabled filesystems won't have this problem, so leave the code that has already been written ifdef'd out until the proper time. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: verify AGI blocks as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | Add an AGI block verify callback function and pass it into the buffer read functions. Remove the now redundant verification code that is currently in use. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: verify AGF blocks as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | | Add an AGF block verify callback function and pass it into the buffer read functions. This replaces the existing verification that is done after the read completes. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: verify superblocks as they are read from diskDave Chinner2012-11-15
| | | | | | | | | | | | | | | | | Add a superblock verify callback function and pass it into the buffer read functions. Remove the now redundant verification code that is currently in use. Adding verification shows that secondary superblocks never have their "sb_inprogress" flag cleared by mkfs.xfs, so when validating the secondary superblocks during a grow operation we have to avoid checking this field. Even if we fix mkfs, we will still have to ignore this field for verification purposes unless a version of mkfs that does not have this bug was used. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: uncached buffer reads need to return an errorDave Chinner2012-11-15
| | | | | | | | | | | | | | | | | With verification being done as an IO completion callback, different errors can be returned from a read. Uncached reads only return a buffer or NULL on failure, which means the verification error cannot be returned to the caller. Split the error handling for these reads into two - a failure to get a buffer will still return NULL, but a read error will return a referenced buffer with b_error set rather than NULL. The caller is responsible for checking the error state of the buffer returned. 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>
* xfs: make buffer read verication an IO completion functionDave Chinner2012-11-15
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* xfs: remove xfs_flushinval_pagesDave Chinner2012-11-14
| | | | | | | | | | | | It's just a simple wrapper around VFS functionality, and is actually bugging in that it doesn't remove mappings before invalidating the page cache. Remove it and replace it with the correct VFS functionality. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Andrew Dahl <adahl@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: remove xfs_flush_pagesDave Chinner2012-11-14
| | | | | | | | | | | | | | | | It is a complex wrapper around VFS functions, but there are VFS functions that provide exactly the same functionality. Call the VFS functions directly and remove the unnecessary indirection and complexity. We don't need to care about clearing the XFS_ITRUNCATED flag, as that is done during .writepages. Hence is cleared by the VFS writeback path if there is anything to write back during the flush. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Andrew Dahl <adahl@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: remove xfs_wait_on_pages()Dave Chinner2012-11-14
| | | | | | | | | | | It's just a simple wrapper around a VFS function that is only called by another function in xfs_fs_subr.c. Remove it and call the VFS function directly. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Andrew Dahl <adahl@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: reverse the check on XFS_IOC_ZERO_RANGEAndrew Dahl2012-11-14
| | | | | | | | | | | Reversing the check on XFS_IOC_ZERO_RANGE. Range should be zeroed if the start is less than or equal to the end. Signed-off-by: Andrew Dahl <adahl@sgi.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: remove xfs_tosspagesDave Chinner2012-11-14
| | | | | | | | | | | | | | | | | It's a buggy, unnecessary wrapper that is duplicating truncate_pagecache_range(). When replacing the call in xfs_change_file_space(), also ensure that the length being allocated/freed is always positive before making any changes. These checks are done in the lower extent manipulation functions, too, but we need to do them before any page cache operations. Reported-by: Andrew Dahl <adahl@sgi.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-By: Andrew Dahl <adahl@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: make growfs initialise the AGFL headerDave Chinner2012-11-13
| | | | | | | | | | | | | | | | For verification purposes, AGFLs need to be initialised to a known set of values. For upcoming CRC changes, they are also headers that need to be initialised. Currently, growfs does neither for the AGFLs - it ignores them completely. Add initialisation of the AGFL to be full of invalid block numbers (NULLAGBLOCK) to put the infrastructure in place needed for CRC support. Includes a comment clarification from Jeff Liu. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by Rich Johnston <rjohnston@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: growfs: use uncached buffers for new headersDave Chinner2012-11-13
| | | | | | | | | | | | | | | | | | | | | | | | When writing the new AG headers to disk, we can't attach write verifiers because they have a dependency on the struct xfs-perag being attached to the buffer to be fully initialised and growfs can't fully initialise them until later in the process. The simplest way to avoid this problem is to use uncached buffers for writing the new headers. These buffers don't have the xfs-perag attached to them, so it's simple to detect in the write verifier and be able to skip the checks that need the xfs-perag. This enables us to attach the appropriate buffer ops to the buffer and hence calculate CRCs on the way to disk. IT also means that the buffer is torn down immediately, and so the first access to the AG headers will re-read the header from disk and perform full verification of the buffer. This way we also can catch corruptions due to problems that went undetected in growfs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by Rich Johnston <rjohnston@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: use btree block initialisation functions in growfsDave Chinner2012-11-13
| | | | | | | | | | | Factor xfs_btree_init_block() to be independent of the btree cursor, and use the function to initialise btree blocks in the growfs code. This makes adding support for different format btree blocks simple. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by Rich Johnston <rjohnston@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add more attribute tree trace points.Dave Chinner2012-11-13
| | | | | | | | | | | Added when debugging recent attribute tree problems to more finely trace code execution through the maze of twisty passages that makes up the attr code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: drop buffer io reference when a bad bio is builtDave Chinner2012-11-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Error handling in xfs_buf_ioapply_map() does not handle IO reference counts correctly. We increment the b_io_remaining count before building the bio, but then fail to decrement it in the failure case. This leads to the buffer never running IO completion and releasing the reference that the IO holds, so at unmount we can leak the buffer. This leak is captured by this assert failure during unmount: XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0, file: fs/xfs/xfs_mount.c, line: 273 This is not a new bug - the b_io_remaining accounting has had this problem for a long, long time - it's just very hard to get a zero length bio being built by this code... Further, the buffer IO error can be overwritten on a multi-segment buffer by subsequent bio completions for partial sections of the buffer. Hence we should only set the buffer error status if the buffer is not already carrying an error status. This ensures that a partial IO error on a multi-segment buffer will not be lost. This part of the problem is a regression, however. cc: <stable@vger.kernel.org> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: fix broken error handling in xfs_vm_writepageDave Chinner2012-11-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we shut down the filesystem, it might first be detected in writeback when we are allocating a inode size transaction. This happens after we have moved all the pages into the writeback state and unlocked them. Unfortunately, if we fail to set up the transaction we then abort writeback and try to invalidate the current page. This then triggers are BUG() in block_invalidatepage() because we are trying to invalidate an unlocked page. Fixing this is a bit of a chicken and egg problem - we can't allocate the transaction until we've clustered all the pages into the IO and we know the size of it (i.e. whether the last block of the IO is beyond the current EOF or not). However, we don't want to hold pages locked for long periods of time, especially while we lock other pages to cluster them into the write. To fix this, we need to make a clear delineation in writeback where errors can only be handled by IO completion processing. That is, once we have marked a page for writeback and unlocked it, we have to report errors via IO completion because we've already started the IO. We may not have submitted any IO, but we've changed the page state to indicate that it is under IO so we must now use the IO completion path to report errors. To do this, add an error field to xfs_submit_ioend() to pass it the error that occurred during the building on the ioend chain. When this is non-zero, mark each ioend with the error and call xfs_finish_ioend() directly rather than building bios. This will immediately push the ioends through completion processing with the error that has occurred. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: fix attr tree double split corruptionDave Chinner2012-11-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In certain circumstances, a double split of an attribute tree is needed to insert or replace an attribute. In rare situations, this can go wrong, leaving the attribute tree corrupted. In this case, the attr being replaced is the last attr in a leaf node, and the replacement is larger so doesn't fit in the same leaf node. When we have the initial condition of a node format attribute btree with two leaves at index 1 and 2. Call them L1 and L2. The leaf L1 is completely full, there is not a single byte of free space in it. L2 is mostly empty. The attribute being replaced - call it X - is the last attribute in L1. The way an attribute replace is executed is that the replacement attribute - call it Y - is first inserted into the tree, but has an INCOMPLETE flag set on it so that list traversals ignore it. Once this transaction is committed, a second transaction it run to atomically mark Y as COMPLETE and X as INCOMPLETE, so that a traversal will now find Y and skip X. Once that transaction is committed, attribute X is then removed. So, the initial condition is: +--------+ +--------+ | L1 | | L2 | | fwd: 2 |---->| fwd: 0 | | bwd: 0 |<----| bwd: 1 | | fsp: 0 | | fsp: N | |--------| |--------| | attr A | | attr 1 | |--------| |--------| | attr B | | attr 2 | |--------| |--------| .......... .......... |--------| |--------| | attr X | | attr n | +--------+ +--------+ So now we go to replace X, and see that L1:fsp = 0 - it is full so we can't insert Y in the same leaf. So we record the the location of attribute X so we can track it for later use, then we split L1 into L1 and L3 and reblance across the two leafs. We end with: +--------+ +--------+ +--------+ | L1 | | L3 | | L2 | | fwd: 3 |---->| fwd: 2 |---->| fwd: 0 | | bwd: 0 |<----| bwd: 1 |<----| bwd: 3 | | fsp: M | | fsp: J | | fsp: N | |--------| |--------| |--------| | attr A | | attr X | | attr 1 | |--------| +--------+ |--------| | attr B | | attr 2 | |--------| |--------| .......... .......... |--------| |--------| | attr W | | attr n | +--------+ +--------+ And we track that the original attribute is now at L3:0. We then try to insert Y into L1 again, and find that there isn't enough room because the new attribute is larger than the old one. Hence we have to split again to make room for Y. We end up with this: +--------+ +--------+ +--------+ +--------+ | L1 | | L4 | | L3 | | L2 | | fwd: 4 |---->| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 | | bwd: 0 |<----| bwd: 1 |<----| bwd: 4 |<----| bwd: 3 | | fsp: M | | fsp: J | | fsp: J | | fsp: N | |--------| |--------| |--------| |--------| | attr A | | attr Y | | attr X | | attr 1 | |--------| + INCOMP + +--------+ |--------| | attr B | +--------+ | attr 2 | |--------| |--------| .......... .......... |--------| |--------| | attr W | | attr n | +--------+ +--------+ And now we have the new (incomplete) attribute @ L4:0, and the original attribute at L3:0. At this point, the first transaction is committed, and we move to the flipping of the flags. This is where we are supposed to end up with this: +--------+ +--------+ +--------+ +--------+ | L1 | | L4 | | L3 | | L2 | | fwd: 4 |---->| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 | | bwd: 0 |<----| bwd: 1 |<----| bwd: 4 |<----| bwd: 3 | | fsp: M | | fsp: J | | fsp: J | | fsp: N | |--------| |--------| |--------| |--------| | attr A | | attr Y | | attr X | | attr 1 | |--------| +--------+ + INCOMP + |--------| | attr B | +--------+ | attr 2 | |--------| |--------| .......... .......... |--------| |--------| | attr W | | attr n | +--------+ +--------+ But that doesn't happen properly - the attribute tracking indexes are not pointing to the right locations. What we end up with is both the old attribute to be removed pointing at L4:0 and the new attribute at L4:1. On a debug kernel, this assert fails like so: XFS: Assertion failed: args->index2 < be16_to_cpu(leaf2->hdr.count), file: fs/xfs/xfs_attr_leaf.c, line: 2725 because the new attribute location does not exist. On a production kernel, this goes unnoticed and the code proceeds ahead merrily and removes L4 because it thinks that is the block that is no longer needed. This leaves the hash index node pointing to entries L1, L4 and L2, but only blocks L1, L3 and L2 to exist. Further, the leaf level sibling list is L1 <-> L4 <-> L2, but L4 is now free space, and so everything is busted. This corruption is caused by the removal of the old attribute triggering a join - it joins everything correctly but then frees the wrong block. xfs_repair will report something like: bad sibling back pointer for block 4 in attribute fork for inode 131 problem with attribute contents in inode 131 would clear attr fork bad nblocks 8 for inode 131, would reset to 3 bad anextents 4 for inode 131, would reset to 0 The problem lies in the assignment of the old/new blocks for tracking purposes when the double leaf split occurs. The first split tries to place the new attribute inside the current leaf (i.e. "inleaf == true") and moves the old attribute (X) to the new block. This sets up the old block/index to L1:X, and newly allocated block to L3:0. It then moves attr X to the new block and tries to insert attr Y at the old index. That fails, so it splits again. With the second split, the rebalance ends up placing the new attr in the second new block - L4:0 - and this is where the code goes wrong. What is does is it sets both the new and old block index to the second new block. Hence it inserts attr Y at the right place (L4:0) but overwrites the current location of the attr to replace that is held in the new block index (currently L3:0). It over writes it with L4:1 - the index we later assert fail on. Hopefully this table will show this in a foramt that is a bit easier to understand: Split old attr index new attr index vanilla patched vanilla patched before 1st L1:26 L1:26 N/A N/A after 1st L3:0 L3:0 L1:26 L1:26 after 2nd L4:0 L3:0 L4:1 L4:0 ^^^^ ^^^^ wrong wrong The fix is surprisingly simple, for all this analysis - just stop the rebalance on the out-of leaf case from overwriting the new attr index - it's already correct for the double split case. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add background scanning to clear eofblocks inodesBrian Foster2012-11-08
| | | | | | | | | | | | | | | | | | Create a new mount workqueue and delayed_work to enable background scanning and freeing of eofblocks inodes. The scanner kicks in once speculative preallocation occurs and stops requeueing itself when no eofblocks inodes exist. The scan interval is based on the new 'speculative_prealloc_lifetime' tunable (default to 5m). The background scanner performs unfiltered, best effort scans (which skips inodes under lock contention or with a dirty cache mapping). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add minimum file size filtering to eofblocks scanBrian Foster2012-11-08
| | | | | | | | | | | | Support minimum file size filtering in the eofblocks scan. The caller must set the XFS_EOF_FLAGS_MINFILESIZE flags bit and minimum file size value in bytes. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: support multiple inode id filtering in eofblocks scanBrian Foster2012-11-08
| | | | | | | | | | | | Enhance the eofblocks scan code to filter based on multiply specified inode id values. When multiple inode id values are specified, only inodes that match all id values are selected. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add inode id filtering to eofblocks scanBrian Foster2012-11-08
| | | | | | | | | | | Support inode ID filtering in the eofblocks scan. The caller must set the associated XFS_EOF_FLAGS_*ID bit and ID field. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add XFS_IOC_FREE_EOFBLOCKS ioctlBrian Foster2012-11-08
| | | | | | | | | | | | The XFS_IOC_FREE_EOFBLOCKS ioctl allows users to invoke an EOFBLOCKS scan. The xfs_eofblocks structure is defined to support the command parameters (scan mode). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: create function to scan and clear EOFBLOCKS inodesBrian Foster2012-11-08
| | | | | | | | | | | | | | | | | | | xfs_inodes_free_eofblocks() implements scanning functionality for EOFBLOCKS inodes. It uses the AG iterator to walk the tagged inodes and free post-EOF blocks via the xfs_inode_free_eofblocks() execute function. The scan can be invoked in best-effort mode or wait (force) mode. A best-effort scan (default) handles all inodes that do not have a dirty cache and we successfully acquire the io lock via trylock. In wait mode, we continue to cycle through an AG until all inodes are handled. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: make xfs_free_eofblocks() non-static, return EAGAIN on trylock failureBrian Foster2012-11-08
| | | | | | | | | | | | Turn xfs_free_eofblocks() into a non-static function, return EAGAIN to indicate trylock failure and make sure this error is not propagated in xfs_release(). Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: create helper to check whether to free eofblocks on inodeBrian Foster2012-11-08
| | | | | | | | | | | | | | | | | | This check is used in multiple places to determine whether we should check for (and potentially free) post EOF blocks on an inode. Add a helper to consolidate the check. Note that when we remove an inode from the cache (xfs_inactive()), we are required to trim post-EOF blocks even if the inode is marked preallocated or append-only to maintain correct space accounting. The 'force' parameter to xfs_can_free_eofblocks() specifies whether we should ignore the prealloc/append-only status of the inode. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: support a tag-based inode_ag_iteratorBrian Foster2012-11-08
| | | | | | | | | | | | | Genericize xfs_inode_ag_walk() to support an optional radix tree tag and args argument for the execute function. Create a new wrapper called xfs_inode_ag_iterator_tag() that performs a tag based walk of perag's and inodes. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: add EOFBLOCKS inode tagging/untaggingBrian Foster2012-11-08
| | | | | | | | | | | | | | | | | | | | | | Add the XFS_ICI_EOFBLOCKS_TAG inode tag to identify inodes with speculatively preallocated blocks beyond EOF. An inode is tagged when speculative preallocation occurs and untagged either via truncate down or when post-EOF blocks are freed via release or reclaim. The tag management is intentionally not aggressive to prefer simplicity over the complexity of handling all the corner cases under which post-EOF blocks could be freed (i.e., forward truncation, fallocate, write error conditions, etc.). This means that a tagged inode may or may not have post-EOF blocks after a period of time. The tag is eventually cleared when the inode is released or reclaimed. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
* xfs: report projid32bit feature in geometry callEric Sandeen2012-11-07
| | | | | | | | | | | | When xfs gained the projid32bit feature, it was never added to the FSGEOMETRY ioctl feature flags, so it's not queryable without this patch. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-18 08:45:14 -0500