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| * | | | | | | | | | NFSD: Implement the COPY callAnna Schumaker2016-10-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I only implemented the sync version of this call, since it's the easiest. I can simply call vfs_copy_range() and have the vfs do the right thing for the filesystem being exported. Signed-off-by: Anna Schumaker <bjschuma@netapp.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: handle EUCLEANJ. Bruce Fields2016-10-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eric Sandeen reports that xfs can return this if filesystem corruption prevented completing the operation. Reported-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: only WARN once on unmapped errorsJ. Bruce Fields2016-10-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No need to spam the logs here. The only drawback is losing information if we ever encounter two different unmapped errors, but in practice we've rarely see even one. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | exportfs: be careful to only return expected errors.NeilBrown2016-10-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When nfsd calls fh_to_dentry, it expect ESTALE or ENOMEM as errors. In particular it can be tempting to return ENOENT, but this is not handled well by nfsd. Rather than requiring strict adherence to error code code filesystems, treat all unexpected error codes the same as ESTALE. This is safest. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd4: setclientid_confirm with unmatched verifier should failJ. Bruce Fields2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A setclientid_confirm with (clientid, verifier) both matching an existing confirmed record is assumed to be a replay, but if the verifier doesn't match, it shouldn't be. This would be a very rare case, except that clients following https://tools.ietf.org/html/rfc7931#section-5.8 may depend on the failure. Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: randomize SETCLIENTID reply to help distinguish serversJ. Bruce Fields2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NFSv4.1 has built-in trunking support that allows a client to determine whether two connections to two different IP addresses are actually to the same server. NFSv4.0 does not, but RFC 7931 attempts to provide clients a means to do this, basically by performing a SETCLIENTID to one address and confirming it with a SETCLIENTID_CONFIRM to the other. Linux clients since 05f4c350ee02 "NFS: Discover NFSv4 server trunking when mounting" implement a variation on this suggestion. It is possible that other clients do too. This depends on the clientid and verifier not being accepted by an unrelated server. Since both are 64-bit values, that would be very unlikely if they were random numbers. But they aren't: knfsd generates the 64-bit clientid by concatenating the 32-bit boot time (in seconds) and a counter. This makes collisions between clientids generated by the same server extremely unlikely. But collisions are very likely between clientids generated by servers that boot at the same time, and it's quite common for multiple servers to boot at the same time. The verifier is a concatenation of the SETCLIENTID time (in seconds) and a counter, so again collisions between different servers are likely if multiple SETCLIENTIDs are done at the same time, which is a common case. Therefore recent NFSv4.0 clients may decide two different servers are really the same, and mount a filesystem from the wrong server. Fortunately the Linux client, since 55b9df93ddd6 "nfsv4/v4.1: Verify the client owner id during trunking detection", only does this when given the non-default "migration" mount option. The fault is really with RFC 7931, and needs a client fix, but in the meantime we can mitigate the chance of these collisions by randomizing the starting value of the counters used to generate clientids and verifiers. Reported-by: Frank Sorenson <fsorenso@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: set the MAY_NOTIFY_LOCK flag in OPEN repliesJeff Layton2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we are using v4.1+, then we can send notification when contended locks become free. Inform the client of that fact. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: add a LRU list for blocked locksJeff Layton2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's possible for a client to call in on a lock that is blocked for a long time, but discontinue polling for it. A malicious client could even set a lock on a file, and then spam the server with failing lock requests from different lockowners that pile up in a DoS attack. Add the blocked lock structures to a per-net namespace LRU when hashing them, and timestamp them. If the lock request is not revisited after a lease period, we'll drop it under the assumption that the client is no longer interested. This also gives us a mechanism to clean up these objects at server shutdown time as well. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: have nfsd4_lock use blocking locks for v4.1+ locksJeff Layton2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a new per-lockowner+per-inode structure that contains a file_lock. Have nfsd4_lock add this structure to the lockowner's list prior to setting the lock. Then call the vfs and request a blocking lock (by setting FL_SLEEP). If we get anything besides FILE_LOCK_DEFERRED back, then we dequeue the block structure and free it. When the next lock request comes in, we'll look for an existing block for the same filehandle and dequeue and reuse it if there is one. When the lock comes free (a'la an lm_notify call), we dequeue it from the lockowner's list and kick off a CB_NOTIFY_LOCK callback to inform the client that it should retry the lock request. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: plumb in a CB_NOTIFY_LOCK operationJeff Layton2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the encoding/decoding for CB_NOTIFY_LOCK operations. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | NFSD: fix corruption in notifier registrationVasily Averin2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | By design notifier can be registered once only, however nfsd registers the same inetaddr notifiers per net-namespace. When this happen it corrupts list of notifiers, as result some notifiers can be not called on proper event, traverse on list can be cycled forever, and second unregister can access already freed memory. Cc: stable@vger.kernel.org fixes: 36684996 ("nfsd: Register callbacks on the inetaddr_chain and inet6addr_chain") Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: fix dprintk in nfsd4_encode_getdeviceinfoJeff Layton2016-09-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nfserr is big-endian, so we should convert it to host-endian before printing it. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: eliminate cb_minorversion fieldJeff Layton2016-09-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We already have that info in the client pointer. No need to pass around a copy. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| * | | | | | | | | | nfsd: don't set a FL_LAYOUT lease for flexfiles layoutsJeff Layton2016-09-16
| | |_|/ / / / / / / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently can hit a deadlock (of sorts) when trying to use flexfiles layouts with XFS. XFS will call break_layout when something wants to write to the file. In the case of the (super-simple) flexfiles layout driver in knfsd, the MDS and DS are the same machine. The client can get a layout and then issue a v3 write to do its I/O. XFS will then call xfs_break_layouts, which will cause a CB_LAYOUTRECALL to be issued to the client. The client however can't return the layout until the v3 WRITE completes, but XFS won't allow the write to proceed until the layout is returned. Christoph says: XFS only cares about block-like layouts where the client has direct access to the file blocks. I'd need to look how to propagate the flag into break_layout, but in principle we don't need to do any recalls on truncate ever for file and flexfile layouts. If we're never going to recall the layout, then we don't even need to set the lease at all. Just skip doing so on flexfiles layouts by adding a new flag to struct nfsd4_layout_ops and skipping the lease setting and removal when that flag is true. Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
* | | | | | | | | | Merge tag 'xfs-reflink-for-linus-4.9-rc1' of ↵Linus Torvalds2016-10-13
|\ \ \ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs < XFS has gained super CoW powers! > ---------------------------------- \ ^__^ \ (oo)\_______ (__)\ )\/\ ||----w | || || Pull XFS support for shared data extents from Dave Chinner: "This is the second part of the XFS updates for this merge cycle. This pullreq contains the new shared data extents feature for XFS. Given the complexity and size of this change I am expecting - like the addition of reverse mapping last cycle - that there will be some follow-up bug fixes and cleanups around the -rc3 stage for issues that I'm sure will show up once the code hits a wider userbase. What it is: At the most basic level we are simply adding shared data extents to XFS - i.e. a single extent on disk can now have multiple owners. To do this we have to add new on-disk features to both track the shared extents and the number of times they've been shared. This is done by the new "refcount" btree that sits in every allocation group. When we share or unshare an extent, this tree gets updated. Along with this new tree, the reverse mapping tree needs to be updated to track each owner or a shared extent. This also needs to be updated ever share/unshare operation. These interactions at extent allocation and freeing time have complex ordering and recovery constraints, so there's a significant amount of new intent-based transaction code to ensure that operations are performed atomically from both the runtime and integrity/crash recovery perspectives. We also need to break sharing when writes hit a shared extent - this is where the new copy-on-write implementation comes in. We allocate new storage and copy the original data along with the overwrite data into the new location. We only do this for data as we don't share metadata at all - each inode has it's own metadata that tracks the shared data extents, the extents undergoing CoW and it's own private extents. Of course, being XFS, nothing is simple - we use delayed allocation for CoW similar to how we use it for normal writes. ENOSPC is a significant issue here - we build on the reservation code added in 4.8-rc1 with the reverse mapping feature to ensure we don't get spurious ENOSPC issues part way through a CoW operation. These mechanisms also help minimise fragmentation due to repeated CoW operations. To further reduce fragmentation overhead, we've also introduced a CoW extent size hint, which indicates how large a region we should allocate when we execute a CoW operation. With all this functionality in place, we can hook up .copy_file_range, .clone_file_range and .dedupe_file_range and we gain all the capabilities of reflink and other vfs provided functionality that enable manipulation to shared extents. We also added a fallocate mode that explicitly unshares a range of a file, which we implemented as an explicit CoW of all the shared extents in a file. As such, it's a huge chunk of new functionality with new on-disk format features and internal infrastructure. It warns at mount time as an experimental feature and that it may eat data (as we do with all new on-disk features until they stabilise). We have not released userspace suport for it yet - userspace support currently requires download from Darrick's xfsprogs repo and build from source, so the access to this feature is really developer/tester only at this point. Initial userspace support will be released at the same time the kernel with this code in it is released. The new code causes 5-6 new failures with xfstests - these aren't serious functional failures but things the output of tests changing slightly due to perturbations in layouts, space usage, etc. OTOH, we've added 150+ new tests to xfstests that specifically exercise this new functionality so it's got far better test coverage than any functionality we've previously added to XFS. Darrick has done a pretty amazing job getting us to this stage, and special mention also needs to go to Christoph (review, testing, improvements and bug fixes) and Brian (caught several intricate bugs during review) for the effort they've also put in. Summary: - unshare range (FALLOC_FL_UNSHARE) support for fallocate - copy-on-write extent size hints (FS_XFLAG_COWEXTSIZE) for fsxattr interface - shared extent support for XFS - copy-on-write support for shared extents - copy_file_range support - clone_file_range support (implements reflink) - dedupe_file_range support - defrag support for reverse mapping enabled filesystems" * tag 'xfs-reflink-for-linus-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (71 commits) xfs: convert COW blocks to real blocks before unwritten extent conversion xfs: rework refcount cow recovery error handling xfs: clear reflink flag if setting realtime flag xfs: fix error initialization xfs: fix label inaccuracies xfs: remove isize check from unshare operation xfs: reduce stack usage of _reflink_clear_inode_flag xfs: check inode reflink flag before calling reflink functions xfs: implement swapext for rmap filesystems xfs: refactor swapext code xfs: various swapext cleanups xfs: recognize the reflink feature bit xfs: simulate per-AG reservations being critically low xfs: don't mix reflink and DAX mode for now xfs: check for invalid inode reflink flags xfs: set a default CoW extent size of 32 blocks xfs: convert unwritten status of reverse mappings for shared files xfs: use interval query for rmap alloc operations on shared files xfs: add shared rmap map/unmap/convert log item types xfs: increase log reservations for reflink ...
| * | | | | | | | | | xfs: convert COW blocks to real blocks before unwritten extent conversionChristoph Hellwig2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We need to splice COW blocks we've completed in xfs_end_io_direct_write into the data fork before converting unwritten extents. Otherwise xfs_bmapi_write might first allocate blocks for any holes in the data fork, which isn't only not needed but also harmful as it might cause reserved block underruns in the transaction. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: rework refcount cow recovery error handlingDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The error handling in xfs_refcount_recover_cow_leftovers is confused and can potentially leak memory, so rework it to release resources correctly on error. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: clear reflink flag if setting realtime flagDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we can only turn on the rt flag if there are no data extents, we can safely turn off the reflink flag if the rt flag is being turned on. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: fix error initializationDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eric Sandeen reported a gcc complaint about uninitialized error variables, so fix that. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: fix label inaccuraciesDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we don't unlock anything on the way out, change the label. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: remove isize check from unshare operationDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that fallocate has an explicit unshare flag again, let's try to remove the inode reflink flag whenever the user unshares any part of a file since checking is cheap compared to the CoW. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: reduce stack usage of _reflink_clear_inode_flagDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The loop in _reflink_clear_inode_flag isn't necessary since we jump out if any part of any extent is shared. Remove the loop and we no longer need two maps, so we can save some stack use. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: check inode reflink flag before calling reflink functionsDarrick J. Wong2016-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are a couple of places where we don't check the inode's reflink flag before calling into the reflink code. Fix those, and add some asserts so we don't make this mistake again. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
| * | | | | | | | | | xfs: implement swapext for rmap filesystemsDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement swapext for filesystems that have reverse mapping. Back in the reflink patches, we augmented the bmap code with a 'REMAP' flag that updates only the bmbt and doesn't touch the allocator and implemented log redo items for those two operations. Now we can rewrite extent swapping as a (looong) series of remap operations. This is far less efficient than the fork swapping method implemented in the past, so we only switch this on for rmap. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: refactor swapext codeDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Refactor the swapext function to pull out the fork swapping piece into a separate function. In the next patch we'll add in the bit we need to make it work with rmap filesystems. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: various swapext cleanupsDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace structure typedefs with struct expressions and fix some whitespace issues that result. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: recognize the reflink feature bitDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the reflink feature flag to the set of recognized feature flags. This enables users to write to reflink filesystems. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: simulate per-AG reservations being critically lowDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create an error injection point that enables us to simulate being critically low on per-AG block reservations. This should enable us to simulate this specific ENOSPC condition so that we can test falling back to a regular file copy. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: don't mix reflink and DAX mode for nowDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we don't have a strategy for handling both DAX and reflink, for now we'll just prohibit both being set at the same time. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: check for invalid inode reflink flagsDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't support sharing blocks on the realtime device. Flag inodes with the reflink or cowextsize flags set when the reflink feature is disabled. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: set a default CoW extent size of 32 blocksDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the admin doesn't set a CoW extent size or a regular extent size hint, default to creating CoW reservations 32 blocks long to reduce fragmentation. Signed-off-by: DarricK J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: convert unwritten status of reverse mappings for shared filesDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide a function to convert an unwritten extent to a real one and vice versa when shared extents are possible. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: use interval query for rmap alloc operations on shared filesDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When it's possible for reverse mappings to overlap (data fork extents of files on reflink filesystems), use the interval query function to find the left neighbor of an extent we're trying to add; and be careful to use the lookup functions to update the neighbors and/or add new extents. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: add shared rmap map/unmap/convert log item typesDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wire up some rmap log redo item type codes to map, unmap, or convert shared data block extents. The actual log item recovery comes in a later patch. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: increase log reservations for reflinkDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Increase the log reservations to handle the increased rolling that happens at the end of copy-on-write operations. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: garbage collect old cowextsz reservationsDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trim CoW reservations made on behalf of a cowextsz hint if they get too old or we run low on quota, so long as we don't have dirty data awaiting writeback or directio operations in progress. Garbage collection of the cowextsize extents are kept separate from prealloc extent reaping because setting the CoW prealloc lifetime to a (much) higher value than the regular prealloc extent lifetime has been useful for combatting CoW fragmentation on VM hosts where the VMs experience bursty write behaviors and we can keep the utilization ratios low enough that we don't start to run out of space. IOWs, it benefits us to keep the CoW fork reservations around for as long as we can unless we run out of blocks or hit inode reclaim. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: try other AGs to allocate a BMBT blockDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prior to the introduction of reflink, allocating a block and mapping it into a file was performed in a single transaction with a single block reservation, and the allocator was supposed to find enough blocks to allocate the extent and any BMBT blocks that might be necessary (unless we're low on space). However, due to the way copy on write works, allocation and mapping have been split into two transactions, which means that we must be able to handle the case where we allocate an extent for CoW but that AG runs out of free space before the blocks can be mapped into a file, and the mapping requires a new BMBT block. When this happens, look in one of the other AGs for a BMBT block instead of taking the FS down. The same applies to the functions that convert a data fork to extents and later btree format. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: don't allow reflink when the AG is low on spaceDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the AG free space is down to the reserves, refuse to reflink our way out of space. Hopefully userspace will make a real copy and/or go elsewhere. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: preallocate blocks for worst-case btree expansionDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To gracefully handle the situation where a CoW operation turns a single refcount extent into a lot of tiny ones and then run out of space when a tree split has to happen, use the per-AG reserved block pool to pre-allocate all the space we'll ever need for a maximal btree. For a 4K block size, this only costs an overhead of 0.3% of available disk space. When reflink is enabled, we have an unfortunate problem with rmap -- since we can share a block billions of times, this means that the reverse mapping btree can expand basically infinitely. When an AG is so full that there are no free blocks with which to expand the rmapbt, the filesystem will shut down hard. This is rather annoying to the user, so use the AG reservation code to reserve a "reasonable" amount of space for rmap. We'll prevent reflinks and CoW operations if we think we're getting close to exhausting an AG's free space rather than shutting down, but this permanent reservation should be enough for "most" users. Hopefully. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch@lst.de: ensure that we invalidate the freed btree buffer] Signed-off-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: create a separate cow extent size hint for the allocatorDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a per-inode extent size allocator hint for copy-on-write. This hint is separate from the existing extent size hint so that CoW can take advantage of the fragmentation-reducing properties of extent size hints without disabling delalloc for regular writes. The extent size hint that's fed to the allocator during a copy on write operation is the greater of the cowextsize and regular extsize hint. During reflink, if we're sharing the entire source file to the entire destination file and the destination file doesn't already have a cowextsize hint, propagate the source file's cowextsize hint to the destination file. Furthermore, zero the bulkstat buffer prior to setting the fields so that we don't copy kernel memory contents into userspace. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: unshare a range of blocks via fallocateDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unshare all shared extents if the user calls fallocate with the new unshare mode flag set, so that we can guarantee that a subsequent write will not ENOSPC. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: pass inode instead of file to xfs_reflink_dirty_range, use iomap infrastructure for copy up] Signed-off-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: swap inode reflink flags when swapping inode extentsDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we're swapping the extents of two inodes, be sure to swap the reflink inode flag too. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: teach get_bmapx about shared extents and the CoW forkDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Teach xfs_getbmapx how to report shared extents and CoW fork contents accurately in the bmap output by querying the refcount btree appropriately. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: add dedupe range vfs functionDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define a VFS function which allows userspace to request that the kernel reflink a range of blocks between two files if the ranges' contents match. The function fits the new VFS ioctl that standardizes the checking for the btrfs EXTENT SAME ioctl. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: add clone file and clone range vfs functionsDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define two VFS functions which allow userspace to reflink a range of blocks between two files or to reflink one file's contents to another. These functions fit the new VFS ioctls that standardize the checking for the btrfs CLONE and CLONE RANGE ioctls. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: reflink extents from one file to anotherDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reflink extents from one file to another; that is to say, iteratively remove the mappings from the destination file, copy the mappings from the source file to the destination file, and increment the reference count of all the blocks that got remapped. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: store in-progress CoW allocations in the refcount btreeDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to the way the CoW algorithm in XFS works, there's an interval during which blocks allocated to handle a CoW can be lost -- if the FS goes down after the blocks are allocated but before the block remapping takes place. This is exacerbated by the cowextsz hint -- allocated reservations can sit around for a while, waiting to get used. Since the refcount btree doesn't normally store records with refcount of 1, we can use it to record these in-progress extents. In-progress blocks cannot be shared because they're not user-visible, so there shouldn't be any conflicts with other programs. This is a better solution than holding EFIs during writeback because (a) EFIs can't be relogged currently, (b) even if they could, EFIs are bound by available log space, which puts an unnecessary upper bound on how much CoW we can have in flight, and (c) we already have a mechanism to track blocks. At mount time, read the refcount records and free anything we find with a refcount of 1 because those were in-progress when the FS went down. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: cancel pending CoW reservations when destroying inodesDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When destroying the inode, cancel all pending reservations in the CoW fork so that all the reserved blocks go back to the free pile. In theory this sort of cleanup is only needed to clean up after write errors. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: cancel CoW reservations and clear inode reflink flag when freeing blocksDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we're freeing blocks (truncate, punch, etc.), clear all CoW reservations in the range being freed. If the file block count drops to zero, also clear the inode reflink flag. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * | | | | | | | | | xfs: implement CoW for directio writesDarrick J. Wong2016-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For O_DIRECT writes to shared blocks, we have to CoW them just like we would with buffered writes. For writes that are not block-aligned, just bounce them to the page cache. For block-aligned writes, however, we can do better than that. Use the same mechanisms that we employ for buffered CoW to set up a delalloc reservation, allocate all the blocks at once, issue the writes against the new blocks and use the same ioend functions to remap the blocks after the write. This should be fairly performant. Christoph discovered that xfs_reflink_allocate_cow_range may stumble over invalid entries in the extent array given that it drops the ilock but still expects the index to be stable. Simple fixing it to a new lookup for every iteration still isn't correct given that xfs_bmapi_allocate will trigger a BUG_ON() if hitting a hole, and there is nothing preventing a xfs_bunmapi_cow call removing extents once we dropped the ilock either. This patch duplicates the inner loop of xfs_bmapi_allocate into a helper for xfs_reflink_allocate_cow_range so that it can be done under the same ilock critical section as our CoW fork delayed allocation. The directio CoW warts will be revisited in a later patch. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de>