kernel.git/fs/xfs/libxfs, branch linux-4.13.y

xfs: trim writepage mapping to within eof

2017-10-27T08:39:17Z

commit 40214d128e07dd21bb07a8ed6a7fe2f911281ab2 upstream. The writeback rework in commit fbcc02561359 ("xfs: Introduce writeback context for writepages") introduced a subtle change in behavior with regard to the block mapping used across the ->writepages() sequence. The previous xfs_cluster_write() code would only flush pages up to EOF at the time of the writepage, thus ensuring that any pages due to file-extending writes would be handled on a separate cycle and with a new, updated block mapping. The updated code establishes a block mapping in xfs_writepage_map() that could extend beyond EOF if the file has post-eof preallocation. Because we now use the generic writeback infrastructure and pass the cached mapping to each writepage call, there is no implicit EOF limit in place. If eofblocks trimming occurs during ->writepages(), any post-eof portion of the cached mapping becomes invalid. The eofblocks code has no means to serialize against writeback because there are no pages associated with post-eof blocks. Therefore if an eofblocks trim occurs and is followed by a file-extending buffered write, not only has the mapping become invalid, but we could end up writing a page to disk based on the invalid mapping. Consider the following sequence of events: - A buffered write creates a delalloc extent and post-eof speculative preallocation. - Writeback starts and on the first writepage cycle, the delalloc extent is converted to real blocks (including the post-eof blocks) and the mapping is cached. - The file is closed and xfs_release() trims post-eof blocks. The cached writeback mapping is now invalid. - Another buffered write appends the file with a delalloc extent. - The concurrent writeback cycle picks up the just written page because the writeback range end is LLONG_MAX. xfs_writepage_map() attributes it to the (now invalid) cached mapping and writes the data to an incorrect location on disk (and where the file offset is still backed by a delalloc extent). This problem is reproduced by xfstests test generic/464, which triggers racing writes, appends, open/closes and writeback requests. To address this problem, trim the mapping used during writeback to within EOF when the mapping is validated. This ensures the mapping is revalidated for any pages encountered beyond EOF as of the time the current mapping was cached or last validated. Reported-by: Eryu Guan Diagnosed-by: Eryu Guan Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: handle error if xfs_btree_get_bufs fails

2017-10-27T08:39:17Z

commit 93e8befc17f6d6ea92b0aee3741ceac8bca4590f upstream. Jason reported that a corrupted filesystem failed to replay the log with a metadata block out of bounds warning: XFS (dm-2): _xfs_buf_find: Block out of range: block 0x80270fff8, EOFS 0x9c40000 _xfs_buf_find() and xfs_btree_get_bufs() return NULL if that happens, and then when xfs_alloc_fix_freelist() calls xfs_trans_binval() on that NULL bp, we oops with: BUG: unable to handle kernel NULL pointer dereference at 00000000000000f8 We don't handle _xfs_buf_find errors very well, every caller higher up the stack gets to guess at why it failed. But we should at least handle it somehow, so return EFSCORRUPTED here. Reported-by: Jason L Tibbitts III Signed-off-by: Eric Sandeen Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: Don't log uninitialised fields in inode structures

2017-10-27T08:39:16Z

commit 20413e37d71befd02b5846acdaf5e2564dd1c38e upstream. Prevent kmemcheck from throwing warnings about reading uninitialised memory when formatting inodes into the incore log buffer. There are several issues here - we don't always log all the fields in the inode log format item, and we never log the inode the di_next_unlinked field. In the case of the inode log format item, this is exacerbated by the old xfs_inode_log_format structure padding issue. Hence make the padded, 64 bit aligned version of the structure the one we always use for formatting the log and get rid of the 64 bit variant. This means we'll always log the 64-bit version and so recovery only needs to convert from the unpadded 32 bit version from older 32 bit kernels. Signed-Off-By: Dave Chinner Tested-by: Tetsuo Handa Reviewed-by: Brian Foster Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: perag initialization should only touch m_ag_max_usable for AG 0

2017-10-27T08:39:16Z

commit 9789dd9e1d939232e8ff4c50ef8e75aa6781b3fb upstream. We call __xfs_ag_resv_init to make a per-AG reservation for each AG. This makes the reservation per-AG, not per-filesystem. Therefore, it is incorrect to adjust m_ag_max_usable for each AG. Adjust it only when we're reserving AG 0's blocks so that we only do it once per fs. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster Signed-off-by: Greg Kroah-Hartman

xfs: fix compiler warnings

2017-09-20T06:27:52Z

commit 7bf7a193a90cadccaad21c5970435c665c40fe27 upstream. Fix up all the compiler warnings that have crept in. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

xfs: relog dirty buffers during swapext bmbt owner change

2017-09-20T06:27:51Z

commit 2dd3d709fc4338681a3aa61658122fa8faa5a437 upstream. The owner change bmbt scan that occurs during extent swap operations does not handle ordered buffer failures. Buffers that cannot be marked ordered must be physically logged so previously dirty ranges of the buffer can be relogged in the transaction. Since the bmbt scan may need to process and potentially log a large number of blocks, we can't expect to complete this operation in a single transaction. Update extent swap to use a permanent transaction with enough log reservation to physically log a buffer. Update the bmbt scan to physically log any buffers that cannot be ordered and to terminate the scan with -EAGAIN. On -EAGAIN, the caller rolls the transaction and restarts the scan. Finally, update the bmbt scan helper function to skip bmbt blocks that already match the expected owner so they are not reprocessed after scan restarts. Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig [darrick: fix the xfs_trans_roll call] Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: skip bmbt block ino validation during owner change

2017-09-20T06:27:50Z

commit 99c794c639a65cc7b74f30a674048fd100fe9ac8 upstream. Extent swap uses xfs_btree_visit_blocks() to fix up bmbt block owners on v5 (!rmapbt) filesystems. The bmbt scan uses xfs_btree_lookup_get_block() to read bmbt blocks which verifies the current owner of the block against the parent inode of the bmbt. This works during extent swap because the bmbt owners are updated to the opposite inode number before the inode extent forks are swapped. The modified bmbt blocks are marked as ordered buffers which allows everything to commit in a single transaction. If the transaction commits to the log and the system crashes such that recovery of the extent swap is required, log recovery restarts the bmbt scan to fix up any bmbt blocks that may have not been written back before the crash. The log recovery bmbt scan occurs after the inode forks have been swapped, however. This causes the bmbt block owner verification to fail, leads to log recovery failure and requires xfs_repair to zap the log to recover. Define a new invalid inode owner flag to inform the btree block lookup mechanism that the current inode may be invalid with respect to the current owner of the bmbt block. Set this flag on the cursor used for change owner scans to allow this operation to work at runtime and during log recovery. Signed-off-by: Brian Foster Fixes: bb3be7e7c ("xfs: check for bogus values in btree block headers") Cc: stable@vger.kernel.org Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: don't log dirty ranges for ordered buffers

2017-09-20T06:27:50Z

commit 8dc518dfa7dbd079581269e51074b3c55a65a880 upstream. Ordered buffers are attached to transactions and pushed through the logging infrastructure just like normal buffers with the exception that they are not actually written to the log. Therefore, we don't need to log dirty ranges of ordered buffers. xfs_trans_log_buf() is called on ordered buffers to set up all of the dirty state on the transaction, buffer and log item and prepare the buffer for I/O. Now that xfs_trans_dirty_buf() is available, call it from xfs_trans_ordered_buf() so the latter is now mutually exclusive with xfs_trans_log_buf(). This reflects the implementation of ordered buffers and helps eliminate confusion over the need to log ranges of ordered buffers just to set up internal log state. Signed-off-by: Brian Foster Reviewed-by: Allison Henderson Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: stop searching for free slots in an inode chunk when there are none

2017-09-20T06:27:49Z

commit 2d32311cf19bfb8c1d2b4601974ddd951f9cfd0b upstream. In a filesystem without finobt, the Space manager selects an AG to alloc a new inode, where xfs_dialloc_ag_inobt() will search the AG for the free slot chunk. When the new inode is in the same AG as its parent, the btree will be searched starting on the parent's record, and then retried from the top if no slot is available beyond the parent's record. To exit this loop though, xfs_dialloc_ag_inobt() relies on the fact that the btree must have a free slot available, once its callers relied on the agi->freecount when deciding how/where to allocate this new inode. In the case when the agi->freecount is corrupted, showing available inodes in an AG, when in fact there is none, this becomes an infinite loop. Add a way to stop the loop when a free slot is not found in the btree, making the function to fall into the whole AG scan which will then, be able to detect the corruption and shut the filesystem down. As pointed by Brian, this might impact performance, giving the fact we don't reset the search distance anymore when we reach the end of the tree, giving it fewer tries before falling back to the whole AG search, but it will only affect searches that start within 10 records to the end of the tree. Signed-off-by: Carlos Maiolino Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman

xfs: fix inobt inode allocation search optimization

2017-08-11T23:56:33Z

When we try to allocate a free inode by searching the inobt, we try to find the inode nearest the parent inode by searching chunks both left and right of the chunk containing the parent. As an optimization, we cache the leftmost and rightmost records that we previously searched; if we do another allocation with the same parent inode, we'll pick up the search where it last left off. There's a bug in the case where we found a free inode to the left of the parent's chunk: we need to update the cached left and right records, but because we already reassigned the right record to point to the left, we end up assigning the left record to both the cached left and right records. This isn't a correctness problem strictly, but it can result in the next allocation rechecking chunks unnecessarily or allocating inodes further away from the parent than it needs to. Fix it by swapping the record pointer after we update the cached left and right records. Fixes: bd169565993b ("xfs: speed up free inode search") Signed-off-by: Omar Sandoval Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong