- 17 Feb, 2019 9 commits
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Christoph Hellwig authored
Now that we properly handle the race with truncate in the delalloc allocator there is no need to short cut this exceptional case earlier on. Signed-off-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
Brian Foster <bfoster@redhat.com> Reviewed-by:
Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:
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Christoph Hellwig authored
This function is a small wrapper only used by the writeback code, so move it together with the writeback code and simplify it down to the glorified do { } while loop that is now is. A few bits intentionally got lost here: no need to call xfs_qm_dqattach because quotas are always attached when we create the delalloc reservation, and no need for the imap->br_startblock == 0 check given that xfs_bmapi_convert_delalloc already has a WARN_ON_ONCE for exactly that condition. Signed-off-by: -
Christoph Hellwig authored
This way we can actually count how many bytes got converted and how many calls we need, unlike in the caller which doesn't have the detailed view. Note that this includes a slight change in behavior as the xs_xstrat_quick is now bumped for every allocation instead of just the one covering the requested writeback offset, which makes a lot more sense. Signed-off-by:
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Christoph Hellwig authored
No need to deal with the transaction and the inode locking in the caller. Note that we also switch to passing whichfork as the second paramter, matching what most related functions do. Signed-off-by:
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Christoph Hellwig authored
Delalloc conversion has traditionally been part of our function to allocate blocks on disk (first xfs_bmapi, then xfs_bmapi_write), but delalloc conversion is a little special as we really do not want to allocate blocks over holes, for which we don't have reservations. Split the delalloc conversions into a separate helper to keep the code simple and structured. Signed-off-by:
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Christoph Hellwig authored
We want to be able to reuse them for the upcoming dedidcated delalloc convert routine. Signed-off-by:
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Christoph Hellwig authored
Move boilerplate code from the callers into xfs_bmap_btree_to_extents: - exit early without failure if we don't need to convert to the extent format - assert that we have a btree cursor - don't reinitialize the passed in logflags argument Signed-off-by:
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Christoph Hellwig authored
We already ensure all data fits into s_maxbytes in the write / fault path. The only reason we have them here is that they were copy and pasted from xfs_bmapi_read when we stopped using that function. Signed-off-by:
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Christoph Hellwig authored
The io_type field contains what is basically a summary of information from the inode fork and the imap. But we can just as easily use that information directly, simplifying a few bits here and there and improving the trace points. Signed-off-by:
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- 15 Feb, 2019 3 commits
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Darrick J. Wong authored
When XFS creates an O_TMPFILE file, the inode is created with nlink = 1, put on the unlinked list, and then the VFS sets nlink = 0 in d_tmpfile. If we crash before anything logs the inode (it's dirty incore but the vfs doesn't tell us it's dirty so we never log that change), the iunlink processing part of recovery will then explode with a pile of: XFS: Assertion failed: VFS_I(ip)->i_nlink == 0, file: fs/xfs/xfs_log_recover.c, line: 5072 Worse yet, since nlink is nonzero, the inodes also don't get cleaned up and they just leak until the next xfs_repair run. Therefore, change xfs_iunlink to require that inodes being put on the unlinked list have nlink == 0, change the tmpfile callers to instantiate nodes that way, and set the nlink to 1 just prior to calling d_tmpfile. Fix the comment for xfs_iunlink while we're at it. Signed-off-by:
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Darrick J. Wong authored
Log recovery frees all the inodes stored in the unlinked list, which can cause expansion of the free inode btree. The ifree code skips block reservations if it thinks there's a per-AG space reservation, but we don't set up the reservation until after log recovery, which means that a finobt expansion blows up in xfs_trans_mod_sb when we exceed the transaction's block reservation. To fix this, we set the "no finobt reservation" flag to true when we create the xfs_mount and only set it to false if we confirm that every AG had enough free space to put aside for the finobt. Signed-off-by:
Dave Chinner <dchinner@redhat.com>
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Darrick J. Wong authored
Rename this flag variable to imply more strongly that it's related to the free inode btree (finobt) operation. No functional changes. Signed-off-by:
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- 14 Feb, 2019 1 commit
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Darrick J. Wong authored
For VFS listxattr calls, xfs_xattr_put_listent calls __xfs_xattr_put_listent twice if it sees an attribute "trusted.SGI_ACL_FILE": once for that name, and again for "system.posix_acl_access". Unfortunately, if we happen to run out of buffer space while emitting the first name, we set count to -1 (so that we can feed ERANGE to the caller). The second invocation doesn't check that the context parameters make sense and overwrites the byte before the buffer, triggering a KASAN report: ================================================================== BUG: KASAN: slab-out-of-bounds in strncpy+0xb3/0xd0 Write of size 1 at addr ffff88807fbd317f by task syz/1113 CPU: 3 PID: 1113 Comm: syz Not tainted 5.0.0-rc6-xfsx #rc6 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0xcc/0x180 print_address_description+0x6c/0x23c kasan_report.cold.3+0x1c/0x35 strncpy+0xb3/0xd0 __xfs_xattr_put_listent+0x1a9/0x2c0 [xfs] xfs_attr_list_int_ilocked+0x11af/0x1800 [xfs] xfs_attr_list_int+0x20c/0x2e0 [xfs] xfs_vn_listxattr+0x225/0x320 [xfs] listxattr+0x11f/0x1b0 path_listxattr+0xbd/0x130 do_syscall_64+0x139/0x560 While we're at it we add an assert to the other put_listent to avoid this sort of thing ever happening to the attrlist_by_handle code. Signed-off-by:
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- 12 Feb, 2019 27 commits
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Brian Foster authored
The v5 superblock format added various metadata fields (such as crc, metadata lsn, owner uuid, etc.) to v4 metadata headers or created new v5 headers for blocks where no such headers existed on v4. Where v4 headers did exist, the v5 structures are careful to place v4 metadata at the original location. For example, the magic value is expected to be at the same location in certain blocks to facilitate version detection. While failure of this invariant is likely to cause severe and obvious problems at runtime, we can detect this condition at compile time via the more recently added on-disk format check infrastructure. Since there is no runtime cost, add some offset checks that start with v5 structure definitions, traverse down to the first bit of common metadata with v4 and ensure that common metadata is at the expected offset. Note that we don't care about blocks which had no v4 header because there is no common metadata in those cases. No functional changes. Signed-off-by:
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Darrick J. Wong authored
Now that we encode block magic numbers in all the buffer ops, use that for block type detection in the ag header repair code instead of encoding magics directly in the repair code. Signed-off-by:
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Darrick J. Wong authored
Add dquot magic numbers to the buffer ops type, in case we ever want to use them. Signed-off-by:
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Darrick J. Wong authored
Use xfs_verify_magic to check the magic numbers of inodes. Signed-off-by:
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Brian Foster authored
With the verifier magic value helper in place, we've left a bit more duplicate code across the verifiers that involve struct xfs_da3_blkinfo. This includes the da node, xattr leaf and dir leaf verifiers, all of which perform similar checks for v4 and v5 filesystems. Create a common helper to verify an xfs_da3_blkinfo structure, taking care to only access v5 fields where appropriate, and refactor the aforementioned verifiers to use the helper. No functional changes. Signed-off-by:
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Brian Foster authored
Most buffer verifiers have hardcoded magic value checks conditionalized on the version of the filesystem. The magic value field of the verifier structure facilitates abstraction of some of this code. Populate the ->magic field of various verifiers to take advantage of this abstraction. No functional changes. Signed-off-by:
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Brian Foster authored
The dir2 leaf verifiers share the same underlying structure verification code, but implement six accessor functions to multiplex the code across the two verifiers. Further, the magic value isn't sufficiently abstracted such that the common helper has to manually fix up the magic from the caller on v5 filesystems. Use the magic field in the verifier structure to eliminate the duplicate code and clean this all up. No functional change. Signed-off-by:
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Brian Foster authored
The allocation btree verifiers share code that is unable to detect cross-tree magic value corruptions such as a bnobt block with a cntbt magic value. Populate the b_ops->magic field of the associated verifier structures such that the structure verifier can check the magic value against the expected value based on tree type. The btree level check requires knowledge of the tree type to determine the appropriate maximum value. This was previously part of the hardcoded magic value checks. With that code removed, peek at the first magic value in the verifier to determine the expected tree type of the current block. Signed-off-by:
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Brian Foster authored
Similar to the inode btree verifier, the same allocation btree verifier structure is shared between the by-bno (bnobt) and by-size (cntbt) btrees. This prevents the ability to distinguish magic values between them. Separate the verifier into two, one for each tree, and assign them appropriately. No functional changes. Signed-off-by:
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Brian Foster authored
The inode btree verifier code is shared between the inode btree and free inode btree because the underlying metadata formats are essentially equivalent. A side effect of this is that the verifier cannot determine whether a particular btree block should have an inobt or finobt magic value. This logic allows an unfortunate xfs_repair bug to escape detection where certain level > 0 nodes of the finobt are stamped with inobt magic by xfs_repair finobt reconstruction. This is fortunately not a severe problem since the inode btree magic values do not contribute to any changes in kernel behavior, but we do need a means to detect and prevent this problem in the future. Add a field to xfs_buf_ops to store the v4 and v5 superblock magic values expected by a particular verifier. Add a helper to check an on-disk magic value against the value expected by the verifier. Call the helper from the shared [f]inobt verifier code for magic value verification. This ensures that the inode btree blocks each have the appropriate magic value based on specific tree type and superblock version. Signed-off-by:
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Brian Foster authored
The inobt verifier is reused for the inobt and finobt, which prevents the ability to distinguish between magic values on a per-tree basis. Create a separate finobt structure in preparation for changes to enforce the appropriate magic value for the associated tree. This patch has no functional change. Signed-off-by:
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Brian Foster authored
Most verifiers that check on-disk magic values convert the CPU endian magic value constant to disk endian to facilitate compile time optimization of the byte swap and reduce the need for runtime byte swaps in buffer verifiers. Several buffer verifiers do not follow this pattern. Update those verifiers for consistency. Also fix up a random typo in the inode readahead verifier name. Signed-off-by:
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Brian Foster authored
Improve the documentation around xfs_buf_ensure_ops, which is the function that is responsible for cleaning up the b_ops state of buffers that go through xrep_findroot_block but don't match anything. Rename the function to xfs_buf_reverify. [darrick: this started off as bfoster mods of a previous patch of mine, but the renaming part is now this separate patch.] Signed-off-by:
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Darrick J. Wong authored
Use a rhashtable to cache the unlinked list incore. This should speed up unlinked processing considerably when there are a lot of inodes on the unlinked list because iunlink_remove no longer has to traverse an entire bucket list to find which inode points to the one being removed. The incore list structure records "X.next_unlinked = Y" relations, with the rhashtable using Y to index the records. This makes finding the inode X that points to a inode Y very quick. If our cache fails to find anything we can always fall back on the old method. FWIW this drastically reduces the amount of time it takes to remove inodes from the unlinked list. I wrote a program to open a lot of O_TMPFILE files and then close them in the same order, which takes a very long time if we have to traverse the unlinked lists. With the ptach, I see: + /d/t/tmpfile/tmpfile Opened 193531 files in 6.33s. Closed 193531 files in 5.86s real 0m12.192s user 0m0.064s sys 0m11.619s + cd / + umount /mnt real 0m0.050s user 0m0.004s sys 0m0.030s And without the patch: + /d/t/tmpfile/tmpfile Opened 193588 files in 6.35s. Closed 193588 files in 751.61s real 12m38.853s user 0m0.084s sys 12m34.470s + cd / + umount /mnt real 0m0.086s user 0m0.000s sys 0m0.060s Signed-off-by:
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Darrick J. Wong authored
Add tracepoints so we can associate high level operations with low level updates. No functional changes. Signed-off-by:
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Darrick J. Wong authored
In xfs_iunlink_remove we have two identical calls to xfs_iunlink_update_inode, so move it out of the if statement to simplify the code some more. Signed-off-by:
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Darrick J. Wong authored
There's a loop that searches an unlinked bucket list to find the inode that points to a given inode. Hoist this into a separate function; later we'll use our iunlink backref cache to bypass the slow list operation. No functional changes. Signed-off-by:
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Darrick J. Wong authored
Hoist the functions that update an inode's unlinked pointer updates into a helper. No functional changes. Signed-off-by:
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Darrick J. Wong authored
Strengthen our checking of the AGI unlinked pointers when we start to use them for updating the metadata. Signed-off-by:
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Darrick J. Wong authored
Split the AGI unlinked bucket updates into a separate function. No functional changes. Signed-off-by:
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Darrick J. Wong authored
Add a new helper to check that a per-AG inode pointer is either null or points somewhere valid within that AG. Signed-off-by:
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Darrick J. Wong authored
Fix some indentation issues with the iunlink functions and reorganize the tops of the functions to be identical. No functional changes. Signed-off-by:
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Brian Foster authored
The writeback delalloc conversion code is racy with respect to changes in the currently cached file mapping outside of the current page. This is because the ilock is cycled between the time the caller originally looked up the mapping and across each real allocation of the provided file range. This code has collected various hacks over the years to help combat the symptoms of these races (i.e., truncate race detection, allocation into hole detection, etc.), but none address the fundamental problem that the imap may not be valid at allocation time. Rather than continue to use race detection hacks, update writeback delalloc conversion to a model that explicitly converts the delalloc extent backing the current file offset being processed. The current file offset is the only block we can trust to remain once the ilock is dropped because any operation that can remove the block (truncate, hole punch, etc.) must flush and discard pagecache pages first. Modify xfs_iomap_write_allocate() to use the xfs_bmapi_delalloc() mechanism to request allocation of the entire delalloc extent backing the current offset instead of assuming the extent passed by the caller is unchanged. Record the range specified by the caller and apply it to the resulting allocated extent so previous checks by the caller for COW fork overlap are not lost. Finally, overload the bmapi delalloc flag with the range reval flag behavior since this is the only use case for both. This ensures that writeback always picks up the correct and current extent associated with the page, regardless of races with other extent modifying operations. If operating on a data fork and the COW overlap state has changed since the ilock was cycled, the caller revalidates against the COW fork sequence number before using the imap for the next block. Signed-off-by:
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Brian Foster authored
The writeback delalloc conversion code is racy with respect to changes in the currently cached file mapping. This stems from the fact that the bmapi allocation code requires a file range to allocate and the writeback conversion code assumes the range of the currently cached mapping is still valid with respect to the fork. It may not be valid, however, because the ilock is cycled (potentially multiple times) between the time the cached mapping was populated and the delalloc conversion occurs. To facilitate a solution to this problem, create a new xfs_bmapi_delalloc() wrapper to xfs_bmapi_write() that takes a file (FSB) offset and attempts to allocate whatever delalloc extent backs the offset. Use a new bmapi flag to cause xfs_bmapi_write() to set the range based on the extent backing the bno parameter unless bno lands in a hole. If bno does land in a hole, fall back to the current behavior (which may result in an error or quietly skipping holes in the specified range depending on other parameters). This patch does not change behavior. Signed-off-by:
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Brian Foster authored
Now that the cached writeback mapping is explicitly invalidated on data fork changes, the EOF trimming band-aid is no longer necessary. Remove xfs_trim_extent_eof() as well since it has no other users. Signed-off-by:
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Brian Foster authored
The writeback code caches the current extent mapping across multiple xfs_do_writepage() calls to avoid repeated lookups for sequential pages backed by the same extent. This is known to be slightly racy with extent fork changes in certain difficult to reproduce scenarios. The cached extent is trimmed to within EOF to help avoid the most common vector for this problem via speculative preallocation management, but this is a band-aid that does not address the fundamental problem. Now that we have an xfs_ifork sequence counter mechanism used to facilitate COW writeback, we can use the same mechanism to validate consistency between the data fork and cached writeback mappings. On its face, this is somewhat of a big hammer approach because any change to the data fork invalidates any mapping currently cached by a writeback in progress regardless of whether the data fork change overlaps with the range under writeback. In practice, however, the impact of this approach is minimal in most cases. First, data fork changes (delayed allocations) caused by sustained sequential buffered writes are amortized across speculative preallocations. This means that a cached mapping won't be invalidated by each buffered write of a common file copy workload, but rather only on less frequent allocation events. Second, the extent tree is always entirely in-core so an additional lookup of a usable extent mostly costs a shared ilock cycle and in-memory tree lookup. This means that a cached mapping reval is relatively cheap compared to the I/O itself. Third, spurious invalidations don't impact ioend construction. This means that even if the same extent is revalidated multiple times across multiple writepage instances, we still construct and submit the same size ioend (and bio) if the blocks are physically contiguous. Update struct xfs_writepage_ctx with a new field to hold the sequence number of the data fork associated with the currently cached mapping. Check the wpc seqno against the data fork when the mapping is validated and reestablish the mapping whenever the fork has changed since the mapping was cached. This ensures that writeback always uses a valid extent mapping and thus prevents lost writebacks and stale delalloc block problems. Signed-off-by:
Allison Henderson <allison.henderson@oracle.com> Reviewed-by:
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Brian Foster authored
The sequence counter in the xfs_ifork structure is only updated on COW forks. This is because the counter is currently only used to optimize out repetitive COW fork checks at writeback time. Tweak the extent code to update the seq counter regardless of the fork type in preparation for using this counter on data forks as well. Signed-off-by:
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