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2021-07-21afs: Remove redundant assignment to retJiapeng Chong
Variable ret is set to -ENOENT and -ENOMEM but this value is never read as it is overwritten or not used later on, hence it is a redundant assignment and can be removed. Cleans up the following clang-analyzer warning: fs/afs/dir.c:2014:4: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]. fs/afs/dir.c:659:2: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]. [DH made the following modifications: - In afs_rename(), -ENOMEM should be placed in op->error instead of ret, rather than the assignment being removed entirely. afs_put_operation() will pick it up from there and return it. - If afs_sillyrename() fails, its error code should be placed in op->error rather than in ret also. ] Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/1619691492-83866-1-git-send-email-jiapeng.chong@linux.alibaba.com Link: https://lore.kernel.org/r/162609465444.3133237.7562832521724298900.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162610729052.3408253.17364333638838151299.stgit@warthog.procyon.org.uk/ # v2
2021-07-21afs: Fix setting of writeback_indexDavid Howells
Fix afs_writepages() to always set mapping->writeback_index to a page index and not a byte position[1]. Fixes: 31143d5d515e ("AFS: implement basic file write support") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/162610728339.3408253.4604750166391496546.stgit@warthog.procyon.org.uk/ # v2 (no v1)
2021-07-21afs: check function returnTom Rix
Static analysis reports this problem write.c:773:29: warning: Assigned value is garbage or undefined mapping->writeback_index = next; ^ ~~~~ The call to afs_writepages_region() can return without setting next. So check the function return before using next. Changes: ver #2: - Need to fix the range_cyclic case also[1]. Fixes: e87b03f5830e ("afs: Prepare for use of THPs") Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20210430155031.3287870-1-trix@redhat.com Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1] Link: https://lore.kernel.org/r/162609464716.3133237.10354897554363093252.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162610727640.3408253.8687445613469681311.stgit@warthog.procyon.org.uk/ # v2
2021-07-21afs: Fix tracepoint string placement with built-in AFSDavid Howells
To quote Alexey[1]: I was adding custom tracepoint to the kernel, grabbed full F34 kernel .config, disabled modules and booted whole shebang as VM kernel. Then did perf record -a -e ... It crashed: general protection fault, probably for non-canonical address 0x435f5346592e4243: 0000 [#1] SMP PTI CPU: 1 PID: 842 Comm: cat Not tainted 5.12.6+ #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 RIP: 0010:t_show+0x22/0xd0 Then reproducer was narrowed to # cat /sys/kernel/tracing/printk_formats Original F34 kernel with modules didn't crash. So I started to disable options and after disabling AFS everything started working again. The root cause is that AFS was placing char arrays content into a section full of _pointers_ to strings with predictable consequences. Non canonical address 435f5346592e4243 is "CB.YFS_" which came from CM_NAME macro. Steps to reproduce: CONFIG_AFS=y CONFIG_TRACING=y # cat /sys/kernel/tracing/printk_formats Fix this by the following means: (1) Add enum->string translation tables in the event header with the AFS and YFS cache/callback manager operations listed by RPC operation ID. (2) Modify the afs_cb_call tracepoint to print the string from the translation table rather than using the string at the afs_call name pointer. (3) Switch translation table depending on the service we're being accessed as (AFS or YFS) in the tracepoint print clause. Will this cause problems to userspace utilities? Note that the symbolic representation of the YFS service ID isn't available to this header, so I've put it in as a number. I'm not sure if this is the best way to do this. (4) Remove the name wrangling (CM_NAME) macro and put the names directly into the afs_call_type structs in cmservice.c. Fixes: 8e8d7f13b6d5a9 ("afs: Add some tracepoints") Reported-by: Alexey Dobriyan (SK hynix) <adobriyan@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: Andrew Morton <akpm@linux-foundation.org> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YLAXfvZ+rObEOdc%2F@localhost.localdomain/ [1] Link: https://lore.kernel.org/r/643721.1623754699@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/162430903582.2896199.6098150063997983353.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162609463957.3133237.15916579353149746363.stgit@warthog.procyon.org.uk/ # v1 (repost) Link: https://lore.kernel.org/r/162610726860.3408253.445207609466288531.stgit@warthog.procyon.org.uk/ # v2
2021-06-25Merge tag 'netfs-fixes-20210621' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull netfs fixes from David Howells: "This contains patches to fix netfs_write_begin() and afs_write_end() in the following ways: (1) In netfs_write_begin(), extract the decision about whether to skip a page out to its own helper and have that clear around the region to be written, but not clear that region. This requires the filesystem to patch it up afterwards if the hole doesn't get completely filled. (2) Use offset_in_thp() in (1) rather than manually calculating the offset into the page. (3) Due to (1), afs_write_end() now needs to handle short data write into the page by generic_perform_write(). I've adopted an analogous approach to ceph of just returning 0 in this case and letting the caller go round again. It also adds a note that (in the future) the len parameter may extend beyond the page allocated. This is because the page allocation is deferred to write_begin() and that gets to decide what size of THP to allocate." Jeff Layton points out: "The netfs fix in particular fixes a data corruption bug in cephfs" * tag 'netfs-fixes-20210621' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: netfs: fix test for whether we can skip read when writing beyond EOF afs: Fix afs_write_end() to handle short writes
2021-06-21afs: Fix afs_write_end() to handle short writesDavid Howells
Fix afs_write_end() to correctly handle a short copy into the intended write region of the page. Two things are necessary: (1) If the page is not up to date, then we should just return 0 (ie. indicating a zero-length copy). The loop in generic_perform_write() will go around again, possibly breaking up the iterator into discrete chunks[1]. This is analogous to commit b9de313cf05fe08fa59efaf19756ec5283af672a for ceph. (2) The page should not have been set uptodate if it wasn't completely set up by netfs_write_begin() (this will be fixed in the next patch), so we need to set uptodate here in such a case. Also remove the assertion that was checking that the page was set uptodate since it's now set uptodate if it wasn't already a few lines above. The assertion was from when uptodate was set elsewhere. Changes: v3: Remove the handling of len exceeding the end of the page. Fixes: 3003bbd0697b ("afs: Use the netfs_write_begin() helper") Reported-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> cc: Al Viro <viro@zeniv.linux.org.uk> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YMwVp268KTzTf8cN@zeniv-ca.linux.org.uk/ [1] Link: https://lore.kernel.org/r/162367682522.460125.5652091227576721609.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162391825688.1173366.3437507255136307904.stgit@warthog.procyon.org.uk/ # v2
2021-06-18afs: Re-enable freezing once a page fault is interruptedMatthew Wilcox (Oracle)
If a task is killed during a page fault, it does not currently call sb_end_pagefault(), which means that the filesystem cannot be frozen at any time thereafter. This may be reported by lockdep like this: ==================================== WARNING: fsstress/10757 still has locks held! 5.13.0-rc4-build4+ #91 Not tainted ------------------------------------ 1 lock held by fsstress/10757: #0: ffff888104eac530 ( sb_pagefaults as filesystem freezing is modelled as a lock. Fix this by removing all the direct returns from within the function, and using 'ret' to indicate whether we were interrupted or successful. Fixes: 1cf7a1518aef ("afs: Implement shared-writeable mmap") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20210616154900.1958373-1-willy@infradead.org/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-15afs: Fix an IS_ERR() vs NULL checkDan Carpenter
The proc_symlink() function returns NULL on error, it doesn't return error pointers. Fixes: 5b86d4ff5dce ("afs: Implement network namespacing") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YLjMRKX40pTrJvgf@mwanda/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-07afs: Fix partial writeback of large files on fsync and closeMarc Dionne
In commit e87b03f5830e ("afs: Prepare for use of THPs"), the return value for afs_write_back_from_locked_page was changed from a number of pages to a length in bytes. The loop in afs_writepages_region uses the return value to compute the index that will be used to find dirty pages in the next iteration, but treats it as a number of pages and wrongly multiplies it by PAGE_SIZE. This gives a very large index value, potentially skipping any dirty data that was not covered in the first pass, which is limited to 256M. This causes fsync(), and indirectly close(), to only do a partial writeback of a large file's dirty data. The rest is eventually written back by background threads after dirty_expire_centisecs. Fixes: e87b03f5830e ("afs: Prepare for use of THPs") Signed-off-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20210604175504.4055-1-marc.c.dionne@gmail.com/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-27afs: Fix the nlink handling of dir-over-dir renameDavid Howells
Fix rename of one directory over another such that the nlink on the deleted directory is cleared to 0 rather than being decremented to 1. This was causing the generic/035 xfstest to fail. Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/162194384460.3999479.7605572278074191079.stgit@warthog.procyon.org.uk/ # v1 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-25afs: Fix fall-through warnings for ClangGustavo A. R. Silva
In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple warnings by explicitly adding multiple fallthrough pseudo-keywords in places where the code is intended to fall through to the next case. Link: https://github.com/KSPP/linux/issues/115 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-hardening@vger.kernel.org Link: https://lore.kernel.org/r/51150b54e0b0431a2c401cd54f2c4e7f50e94601.1605896059.git.gustavoars@kernel.org/ # v1 Link: https://lore.kernel.org/r/20210420211615.GA51432@embeddedor/ # v2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-05-01afs: Fix speculative status fetchesDavid Howells
The generic/464 xfstest causes kAFS to emit occasional warnings of the form: kAFS: vnode modified {100055:8a} 30->31 YFS.StoreData64 (c=6015) This indicates that the data version received back from the server did not match the expected value (the DV should be incremented monotonically for each individual modification op committed to a vnode). What is happening is that a lookup call is doing a bulk status fetch speculatively on a bunch of vnodes in a directory besides getting the status of the vnode it's actually interested in. This is racing with a StoreData operation (though it could also occur with, say, a MakeDir op). On the client, a modification operation locks the vnode, but the bulk status fetch only locks the parent directory, so no ordering is imposed there (thereby avoiding an avenue to deadlock). On the server, the StoreData op handler doesn't lock the vnode until it's received all the request data, and downgrades the lock after committing the data until it has finished sending change notifications to other clients - which allows the status fetch to occur before it has finished. This means that: - a status fetch can access the target vnode either side of the exclusive section of the modification - the status fetch could start before the modification, yet finish after, and vice-versa. - the status fetch and the modification RPCs can complete in either order. - the status fetch can return either the before or the after DV from the modification. - the status fetch might regress the locally cached DV. Some of these are handled by the previous fix[1], but that's not sufficient because it checks the DV it received against the DV it cached at the start of the op, but the DV might've been updated in the meantime by a locally generated modification op. Fix this by the following means: (1) Keep track of when we're performing a modification operation on a vnode. This is done by marking vnode parameters with a 'modification' note that causes the AFS_VNODE_MODIFYING flag to be set on the vnode for the duration. (2) Alter the speculation race detection to ignore speculative status fetches if either the vnode is marked as being modified or the data version number is not what we expected. Note that whilst the "vnode modified" warning does get recovered from as it causes the client to refetch the status at the next opportunity, it will also invalidate the pagecache, so changes might get lost. Fixes: a9e5c87ca744 ("afs: Fix speculative status fetch going out of order wrt to modifications") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-and-reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/160605082531.252452.14708077925602709042.stgit@warthog.procyon.org.uk/ [1] Link: https://lore.kernel.org/linux-fsdevel/161961335926.39335.2552653972195467566.stgit@warthog.procyon.org.uk/ # v1 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-04-27Merge tag 'afs-netfs-lib-20210426' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull AFS updates from David Howells: "Use the new netfs lib. Begin the process of overhauling the use of the fscache API by AFS and the introduction of support for features such as Transparent Huge Pages (THPs). - Add some support for THPs, including using core VM helper functions to find details of pages. - Use the ITER_XARRAY I/O iterator to mediate access to the pagecache as this handles THPs and doesn't require allocation of large bvec arrays. - Delegate address_space read/pre-write I/O methods for AFS to the netfs helper library. A method is provided to the library that allows it to issue a read against the server. This includes a change in use for PG_fscache (it now indicates a DIO write in progress from the marked page), so a number of waits need to be deployed for it. - Split the core AFS writeback function to make it easier to modify in future patches to handle writing to the cache. [This might feasibly make more sense moved out into my fscache-iter branch]. I've tested these with "xfstests -g quick" against an AFS volume (xfstests needs patching to make it work). With this, AFS without a cache passes all expected xfstests; with a cache, there's an extra failure, but that's also there before these patches. Fixing that probably requires a greater overhaul (as can be found on my fscache-iter branch, but that's for a later time). Thanks should go to Marc Dionne and Jeff Altman of AuriStor for exercising the patches in their test farm also" Link: https://lore.kernel.org/lkml/3785063.1619482429@warthog.procyon.org.uk/ * tag 'afs-netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Use the netfs_write_begin() helper afs: Use new netfs lib read helper API afs: Use the fs operation ops to handle FetchData completion afs: Prepare for use of THPs afs: Extract writeback extension into its own function afs: Wait on PG_fscache before modifying/releasing a page afs: Use ITER_XARRAY for writing afs: Set up the iov_iter before calling afs_extract_data() afs: Log remote unmarshalling errors afs: Don't truncate iter during data fetch afs: Move key to afs_read struct afs: Print the operation debug_id when logging an unexpected data version afs: Pass page into dirty region helpers to provide THP size afs: Disable use of the fscache I/O routines
2021-04-27Merge branch 'work.inode-type-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs inode type handling updates from Al Viro: "We should never change the type bits of ->i_mode or the method tables (->i_op and ->i_fop) of a live inode. Unfortunately, not all filesystems took care to prevent that" * 'work.inode-type-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: spufs: fix bogosity in S_ISGID handling 9p: missing chunk of "fs/9p: Don't update file type when updating file attributes" openpromfs: don't do unlock_new_inode() until the new inode is set up hostfs_mknod(): don't bother with init_special_inode() cifs: have cifs_fattr_to_inode() refuse to change type on live inode cifs: have ->mkdir() handle race with another client sanely do_cifs_create(): don't set ->i_mode of something we had not created gfs2: be careful with inode refresh ocfs2_inode_lock_update(): make sure we don't change the type bits of i_mode orangefs_inode_is_stale(): i_mode type bits do *not* form a bitmap... vboxsf: don't allow to change the inode type afs: Fix updating of i_mode due to 3rd party change ceph: don't allow type or device number to change on non-I_NEW inodes ceph: fix up error handling with snapdirs new helper: inode_wrong_type()
2021-04-23afs: Use the netfs_write_begin() helperDavid Howells
Make AFS use the new netfs_write_begin() helper to do the pre-reading required before the write. If successful, the helper returns with the required page filled in and locked. It may read more than just one page, expanding the read to meet cache granularity requirements as necessary. Note: A more advanced version of this could be made that does generic_perform_write() for a whole cache granule. This would make it easier to avoid doing the download/read for the data to be overwritten. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588546422.3465195.1546354372589291098.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161539563244.286939.16537296241609909980.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653819291.2770958.406013201547420544.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789102743.6155.17396591236631761195.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Use new netfs lib read helper APIDavid Howells
Make AFS use the new netfs read helpers to implement the VM read operations: - afs_readpage() now hands off responsibility to netfs_readpage(). - afs_readpages() is gone and replaced with afs_readahead(). - afs_readahead() just hands off responsibility to netfs_readahead(). These make use of the cache if a cookie is supplied, otherwise just call the ->issue_op() method a sufficient number of times to complete the entire request. Changes: v5: - Use proper wait function for PG_fscache in afs_page_mkwrite()[1]. - Use killable wait for PG_writeback in afs_page_mkwrite()[1]. v4: - Folded in error handling fixes to afs_req_issue_op(). - Added flag to netfs_subreq_terminated() to indicate that the caller may have been running async and stuff that might sleep needs punting to a workqueue. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/2499407.1616505440@warthog.procyon.org.uk [1] Link: https://lore.kernel.org/r/160588542733.3465195.7526541422073350302.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118158436.1232039.3884845981224091996.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161053540.2537118.14904446369309535330.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340418739.1303470.5908092911600241280.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539561926.286939.5729036262354802339.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653817977.2770958.17696456811587237197.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789101258.6155.3879271028895121537.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Use the fs operation ops to handle FetchData completionDavid Howells
Use the 'success' and 'aborted' afs_operations_ops methods and add a 'failed' method to handle the completion of an AFS.FetchData, AFS.FetchData64 or YFS.FetchData64 RPC operation rather than directly calling the done func pointed to by the afs_read struct from the call delivery handler. This means the done function will be called back on error also, not just on successful completion. This allows motion towards asynchronous data reception on data fetch calls and allows any error to be handed off to the fscache read helper in the same place as a successful completion. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588541471.3465195.8807019223378490810.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118157260.1232039.6549085372718234792.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161052647.2537118.12922380836599003659.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340417106.1303470.3502017303898569631.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539560673.286939.391310781674212229.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653816367.2770958.5856904574822446404.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789099994.6155.473719823490561190.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Prepare for use of THPsDavid Howells
As a prelude to supporting transparent huge pages, use thp_size() and similar rather than PAGE_SIZE/SHIFT. Further, try and frame everything in terms of file positions and lengths rather than page indices and numbers of pages. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588540227.3465195.4752143929716269062.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118155821.1232039.540445038028845740.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161051439.2537118.15577827510426326534.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340415869.1303470.6040191748634322355.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539559365.286939.18344613540296085269.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653815142.2770958.454490670311230206.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789098713.6155.16394227991842480300.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Extract writeback extension into its own functionDavid Howells
Extract writeback extension into its own function to break up the writeback function a bit. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588538471.3465195.782513375683399583.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118154610.1232039.1765365632920504822.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161050546.2537118.2202554806419189453.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340414102.1303470.9078891484034668985.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539558417.286939.2879469588895925399.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653813972.2770958.12671731209438112378.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789097132.6155.4916609419912731964.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Wait on PG_fscache before modifying/releasing a pageDavid Howells
PG_fscache is going to be used to indicate that a page is being written to the cache, and that the page should not be modified or released until it's finished. Make afs_invalidatepage() and afs_releasepage() wait for it. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/158861253957.340223.7465334678444521655.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465832417.1377938.3571599385208729791.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588536286.3465195.13231895135369807920.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118153708.1232039.3535103645871176749.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161049369.2537118.11591934943429117060.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340412903.1303470.6424701655031380012.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539556890.286939.5873470593519458598.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653812726.2770958.18167145829938766503.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789096241.6155.5907241930823579235.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Use ITER_XARRAY for writingDavid Howells
Use a single ITER_XARRAY iterator to describe the portion of a file to be transmitted to the server rather than generating a series of small ITER_BVEC iterators on the fly. This will make it easier to implement AIO in afs. In theory we could maybe use one giant ITER_BVEC, but that means potentially allocating a huge array of bio_vec structs (max 256 per page) when in fact the pagecache already has a structure listing all the relevant pages (radix_tree/xarray) that can be walked over. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/153685395197.14766.16289516750731233933.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/158861251312.340223.17924900795425422532.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465828607.1377938.6903132788463419368.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588535018.3465195.14509994354240338307.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118152415.1232039.6452879415814850025.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161048194.2537118.13763612220937637316.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340411602.1303470.4661108879482218408.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539555629.286939.5241869986617154517.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653811456.2770958.7017388543246759245.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789095005.6155.6789055030327407928.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Set up the iov_iter before calling afs_extract_data()David Howells
afs_extract_data() sets up a temporary iov_iter and passes it to AF_RXRPC each time it is called to describe the remaining buffer to be filled. Instead: (1) Put an iterator in the afs_call struct. (2) Set the iterator for each marshalling stage to load data into the appropriate places. A number of convenience functions are provided to this end (eg. afs_extract_to_buf()). This iterator is then passed to afs_extract_data(). (3) Use the new ITER_XARRAY iterator when reading data to load directly into the inode's pages without needing to create a list of them. This will allow O_DIRECT calls to be supported in future patches. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/152898380012.11616.12094591785228251717.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/153685394431.14766.3178466345696987059.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/153999787395.866.11218209749223643998.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/154033911195.12041.3882700371848894587.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/158861250059.340223.1248231474865140653.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465827399.1377938.11181327349704960046.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588533776.3465195.3612752083351956948.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118151238.1232039.17015723405750601161.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161047240.2537118.14721975104810564022.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340410333.1303470.16260122230371140878.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539554187.286939.15305559004905459852.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653810525.2770958.4630666029125411789.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789093719.6155.7877160739235087723.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Log remote unmarshalling errorsDavid Howells
Log unmarshalling errors reported by the peer (ie. it can't parse what we sent it). Limit the maximum number of messages to 3. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/159465826250.1377938.16372395422217583913.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588532584.3465195.15618385466614028590.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118149739.1232039.208060911149801695.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161046033.2537118.7779717661044373273.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340409118.1303470.17812607349396199116.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539552964.286939.16503232687974398308.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653808989.2770958.11530765353025697860.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789092349.6155.8581594259882708631.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Don't truncate iter during data fetchDavid Howells
Don't truncate the iterator to correspond to the actual data size when fetching the data from the server - rather, pass the length we want to read to rxrpc. This will allow the clear-after-read code in future to simply clear the remaining iterator capacity rather than having to reinitialise the iterator. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/158861249201.340223.13035445866976590375.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465825061.1377938.14403904452300909320.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588531418.3465195.10712005940763063144.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118148567.1232039.13380313332292947956.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161044610.2537118.17908520793806837792.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340407907.1303470.6501394859511712746.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539551721.286939.14655713136572200716.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653807790.2770958.14034599989374173734.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789090823.6155.15673999934535049102.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Move key to afs_read structDavid Howells
Stash the key used to authenticate read operations in the afs_read struct. This will be necessary to reissue the operation against the server if a read from the cache fails in upcoming cache changes. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/158861248336.340223.1851189950710196001.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465823899.1377938.11925978022348532049.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588529557.3465195.7303323479305254243.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118147693.1232039.13780672951838643842.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161043340.2537118.511899217704140722.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340406678.1303470.12676824086429446370.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539550819.286939.1268332875889175195.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653806683.2770958.11300984379283401542.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789089556.6155.14603302893431820997.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Print the operation debug_id when logging an unexpected data versionDavid Howells
Print the afs_operation debug_id when logging an unexpected change in the data version. This allows the logged message to be matched against tracelines. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588528377.3465195.2206051235095182302.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118146111.1232039.11398082422487058312.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161042180.2537118.2471333561661033316.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340405772.1303470.3877167548944248214.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539549628.286939.15234870409714613954.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653805530.2770958.15120507632529970934.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789088290.6155.3494369629853673866.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Pass page into dirty region helpers to provide THP sizeDavid Howells
Pass a pointer to the page being accessed into the dirty region helpers so that the size of the page can be determined in case it's a transparent huge page. This also required the page to be passed into the afs_page_dirty trace point - so there's no need to specifically pass in the index or private data as these can be retrieved directly from the page struct. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/160588527183.3465195.16107942526481976308.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118144921.1232039.11377711180492625929.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161040747.2537118.11435394902674511430.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340404553.1303470.11414163641767769882.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539548385.286939.8864598314493255313.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653804285.2770958.3497360004849598038.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789087043.6155.16922142208140170528.stgit@warthog.procyon.org.uk/ # v6
2021-04-23afs: Disable use of the fscache I/O routinesDavid Howells
Disable use of the fscache I/O routined by the AFS filesystem. It's about to transition to passing iov_iters down and fscache is about to have its I/O path to use iov_iter, so all that needs to change. Signed-off-by: David Howells <dhowells@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/158861209824.340223.1864211542341758994.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/159465768717.1376105.2229314852486665807.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/160588457929.3465195.1730097418904945578.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161118143744.1232039.2727898205333669064.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161039077.2537118.7986870854927176905.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340403323.1303470.8159439948319423431.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539547167.286939.3536238932531122332.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653802797.2770958.547311814861545911.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789085806.6155.2596146255056027428.stgit@warthog.procyon.org.uk/ # v6
2021-03-23afs: Use wait_on_page_writeback_killableMatthew Wilcox (Oracle)
Open-coding this function meant it missed out on the recent bugfix for waiters being woken by a delayed wake event from a previous instantiation of the page[1]. [DH: Changed the patch to use vmf->page rather than variable page which doesn't exist yet upstream] Fixes: 1cf7a1518aef ("afs: Implement shared-writeable mmap") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: kafs-testing@auristor.com cc: linux-afs@lists.infradead.org cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/20210320054104.1300774-4-willy@infradead.org Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c2407cf7d22d0c0d94cf20342b3b8f06f1d904e7 [1]
2021-03-15afs: Stop listxattr() from listing "afs.*" attributesDavid Howells
afs_listxattr() lists all the available special afs xattrs (i.e. those in the "afs.*" space), no matter what type of server we're dealing with. But OpenAFS servers, for example, cannot deal with some of the extra-capable attributes that AuriStor (YFS) servers provide. Unfortunately, the presence of the afs.yfs.* attributes causes errors[1] for anything that tries to read them if the server is of the wrong type. Fix the problem by removing afs_listxattr() so that none of the special xattrs are listed (AFS doesn't support xattrs). It does mean, however, that getfattr won't list them, though they can still be accessed with getxattr() and setxattr(). This can be tested with something like: getfattr -d -m ".*" /afs/example.com/path/to/file With this change, none of the afs.* attributes should be visible. Changes: ver #2: - Hide all of the afs.* xattrs, not just the ACL ones. Fixes: ae46578b963f ("afs: Get YFS ACLs and information through xattrs") Reported-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003502.html [1] Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003567.html # v1 Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003573.html # v2
2021-03-15afs: Fix accessing YFS xattrs on a non-YFS serverDavid Howells
If someone attempts to access YFS-related xattrs (e.g. afs.yfs.acl) on a file on a non-YFS AFS server (such as OpenAFS), then the kernel will jump to a NULL function pointer because the afs_fetch_acl_operation descriptor doesn't point to a function for issuing an operation on a non-YFS server[1]. Fix this by making afs_wait_for_operation() check that the issue_afs_rpc method is set before jumping to it and setting -ENOTSUPP if not. This fix also covers other potential operations that also only exist on YFS servers. afs_xattr_get/set_yfs() then need to translate -ENOTSUPP to -ENODATA as the former error is internal to the kernel. The bug shows up as an oops like the following: BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. [...] Call Trace: afs_wait_for_operation+0x83/0x1b0 [kafs] afs_xattr_get_yfs+0xe6/0x270 [kafs] __vfs_getxattr+0x59/0x80 vfs_getxattr+0x11c/0x140 getxattr+0x181/0x250 ? __check_object_size+0x13f/0x150 ? __fput+0x16d/0x250 __x64_sys_fgetxattr+0x64/0xb0 do_syscall_64+0x49/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fb120a9defe This was triggered with "cp -a" which attempts to copy xattrs, including afs ones, but is easier to reproduce with getfattr, e.g.: getfattr -d -m ".*" /afs/openafs.org/ Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Reported-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003498.html [1] Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003566.html # v1 Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003572.html # v2
2021-03-08afs: Fix updating of i_mode due to 3rd party changeDavid Howells
Fix afs_apply_status() to mask off the irrelevant bits from status->mode when OR'ing them into i_mode. This can happen when a 3rd party chmod occurs. Also fix afs_inode_init_from_status() to mask off the mode bits when initialising i_mode. Fixes: 260a980317da ("[AFS]: Add "directory write" support.") Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-02-23Merge tag 'idmapped-mounts-v5.12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull idmapped mounts from Christian Brauner: "This introduces idmapped mounts which has been in the making for some time. Simply put, different mounts can expose the same file or directory with different ownership. This initial implementation comes with ports for fat, ext4 and with Christoph's port for xfs with more filesystems being actively worked on by independent people and maintainers. Idmapping mounts handle a wide range of long standing use-cases. Here are just a few: - Idmapped mounts make it possible to easily share files between multiple users or multiple machines especially in complex scenarios. For example, idmapped mounts will be used in the implementation of portable home directories in systemd-homed.service(8) where they allow users to move their home directory to an external storage device and use it on multiple computers where they are assigned different uids and gids. This effectively makes it possible to assign random uids and gids at login time. - It is possible to share files from the host with unprivileged containers without having to change ownership permanently through chown(2). - It is possible to idmap a container's rootfs and without having to mangle every file. For example, Chromebooks use it to share the user's Download folder with their unprivileged containers in their Linux subsystem. - It is possible to share files between containers with non-overlapping idmappings. - Filesystem that lack a proper concept of ownership such as fat can use idmapped mounts to implement discretionary access (DAC) permission checking. - They allow users to efficiently changing ownership on a per-mount basis without having to (recursively) chown(2) all files. In contrast to chown (2) changing ownership of large sets of files is instantenous with idmapped mounts. This is especially useful when ownership of a whole root filesystem of a virtual machine or container is changed. With idmapped mounts a single syscall mount_setattr syscall will be sufficient to change the ownership of all files. - Idmapped mounts always take the current ownership into account as idmappings specify what a given uid or gid is supposed to be mapped to. This contrasts with the chown(2) syscall which cannot by itself take the current ownership of the files it changes into account. It simply changes the ownership to the specified uid and gid. This is especially problematic when recursively chown(2)ing a large set of files which is commong with the aforementioned portable home directory and container and vm scenario. - Idmapped mounts allow to change ownership locally, restricting it to specific mounts, and temporarily as the ownership changes only apply as long as the mount exists. Several userspace projects have either already put up patches and pull-requests for this feature or will do so should you decide to pull this: - systemd: In a wide variety of scenarios but especially right away in their implementation of portable home directories. https://systemd.io/HOME_DIRECTORY/ - container runtimes: containerd, runC, LXD:To share data between host and unprivileged containers, unprivileged and privileged containers, etc. The pull request for idmapped mounts support in containerd, the default Kubernetes runtime is already up for quite a while now: https://github.com/containerd/containerd/pull/4734 - The virtio-fs developers and several users have expressed interest in using this feature with virtual machines once virtio-fs is ported. - ChromeOS: Sharing host-directories with unprivileged containers. I've tightly synced with all those projects and all of those listed here have also expressed their need/desire for this feature on the mailing list. For more info on how people use this there's a bunch of talks about this too. Here's just two recent ones: https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf https://fosdem.org/2021/schedule/event/containers_idmap/ This comes with an extensive xfstests suite covering both ext4 and xfs: https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts It covers truncation, creation, opening, xattrs, vfscaps, setid execution, setgid inheritance and more both with idmapped and non-idmapped mounts. It already helped to discover an unrelated xfs setgid inheritance bug which has since been fixed in mainline. It will be sent for inclusion with the xfstests project should you decide to merge this. In order to support per-mount idmappings vfsmounts are marked with user namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects when they are accessed through that mount. By default all vfsmounts are marked with the initial user namespace. The initial user namespace is used to indicate that a mount is not idmapped. All operations behave as before and this is verified in the testsuite. Based on prior discussions we want to attach the whole user namespace and not just a dedicated idmapping struct. This allows us to reuse all the helpers that already exist for dealing with idmappings instead of introducing a whole new range of helpers. In addition, if we decide in the future that we are confident enough to enable unprivileged users to setup idmapped mounts the permission checking can take into account whether the caller is privileged in the user namespace the mount is currently marked with. The user namespace the mount will be marked with can be specified by passing a file descriptor refering to the user namespace as an argument to the new mount_setattr() syscall together with the new MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern of extensibility. The following conditions must be met in order to create an idmapped mount: - The caller must currently have the CAP_SYS_ADMIN capability in the user namespace the underlying filesystem has been mounted in. - The underlying filesystem must support idmapped mounts. - The mount must not already be idmapped. This also implies that the idmapping of a mount cannot be altered once it has been idmapped. - The mount must be a detached/anonymous mount, i.e. it must have been created by calling open_tree() with the OPEN_TREE_CLONE flag and it must not already have been visible in the filesystem. The last two points guarantee easier semantics for userspace and the kernel and make the implementation significantly simpler. By default vfsmounts are marked with the initial user namespace and no behavioral or performance changes are observed. The manpage with a detailed description can be found here: https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8 In order to support idmapped mounts, filesystems need to be changed and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The patches to convert individual filesystem are not very large or complicated overall as can be seen from the included fat, ext4, and xfs ports. Patches for other filesystems are actively worked on and will be sent out separately. The xfstestsuite can be used to verify that port has been done correctly. The mount_setattr() syscall is motivated independent of the idmapped mounts patches and it's been around since July 2019. One of the most valuable features of the new mount api is the ability to perform mounts based on file descriptors only. Together with the lookup restrictions available in the openat2() RESOLVE_* flag namespace which we added in v5.6 this is the first time we are close to hardened and race-free (e.g. symlinks) mounting and path resolution. While userspace has started porting to the new mount api to mount proper filesystems and create new bind-mounts it is currently not possible to change mount options of an already existing bind mount in the new mount api since the mount_setattr() syscall is missing. With the addition of the mount_setattr() syscall we remove this last restriction and userspace can now fully port to the new mount api, covering every use-case the old mount api could. We also add the crucial ability to recursively change mount options for a whole mount tree, both removing and adding mount options at the same time. This syscall has been requested multiple times by various people and projects. There is a simple tool available at https://github.com/brauner/mount-idmapped that allows to create idmapped mounts so people can play with this patch series. I'll add support for the regular mount binary should you decide to pull this in the following weeks: Here's an example to a simple idmapped mount of another user's home directory: u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt u1001@f2-vm:/$ ls -al /home/ubuntu/ total 28 drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 . drwxr-xr-x 4 root root 4096 Oct 28 04:00 .. -rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile -rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ ls -al /mnt/ total 28 drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 . drwxr-xr-x 29 root root 4096 Oct 28 22:01 .. -rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile -rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ touch /mnt/my-file u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file u1001@f2-vm:/$ ls -al /mnt/my-file -rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file u1001@f2-vm:/$ ls -al /home/ubuntu/my-file -rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file u1001@f2-vm:/$ getfacl /mnt/my-file getfacl: Removing leading '/' from absolute path names # file: mnt/my-file # owner: u1001 # group: u1001 user::rw- user:u1001:rwx group::rw- mask::rwx other::r-- u1001@f2-vm:/$ getfacl /home/ubuntu/my-file getfacl: Removing leading '/' from absolute path names # file: home/ubuntu/my-file # owner: ubuntu # group: ubuntu user::rw- user:ubuntu:rwx group::rw- mask::rwx other::r--" * tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits) xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl xfs: support idmapped mounts ext4: support idmapped mounts fat: handle idmapped mounts tests: add mount_setattr() selftests fs: introduce MOUNT_ATTR_IDMAP fs: add mount_setattr() fs: add attr_flags_to_mnt_flags helper fs: split out functions to hold writers namespace: only take read lock in do_reconfigure_mnt() mount: make {lock,unlock}_mount_hash() static namespace: take lock_mount_hash() directly when changing flags nfs: do not export idmapped mounts overlayfs: do not mount on top of idmapped mounts ecryptfs: do not mount on top of idmapped mounts ima: handle idmapped mounts apparmor: handle idmapped mounts fs: make helpers idmap mount aware exec: handle idmapped mounts would_dump: handle idmapped mounts ...
2021-01-29rxrpc: Fix deadlock around release of dst cached on udp tunnelDavid Howells
AF_RXRPC sockets use UDP ports in encap mode. This causes socket and dst from an incoming packet to get stolen and attached to the UDP socket from whence it is leaked when that socket is closed. When a network namespace is removed, the wait for dst records to be cleaned up happens before the cleanup of the rxrpc and UDP socket, meaning that the wait never finishes. Fix this by moving the rxrpc (and, by dependence, the afs) private per-network namespace registrations to the device group rather than subsys group. This allows cached rxrpc local endpoints to be cleared and their UDP sockets closed before we try waiting for the dst records. The symptom is that lines looking like the following: unregister_netdevice: waiting for lo to become free get emitted at regular intervals after running something like the referenced syzbot test. Thanks to Vadim for tracking this down and work out the fix. Reported-by: syzbot+df400f2f24a1677cd7e0@syzkaller.appspotmail.com Reported-by: Vadim Fedorenko <vfedorenko@novek.ru> Fixes: 5271953cad31 ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vadim Fedorenko <vfedorenko@novek.ru> Link: https://lore.kernel.org/r/161196443016.3868642.5577440140646403533.stgit@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-24fs: make helpers idmap mount awareChristian Brauner
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24stat: handle idmapped mountsChristian Brauner
The generic_fillattr() helper fills in the basic attributes associated with an inode. Enable it to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace before we store the uid and gid. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24acl: handle idmapped mountsChristian Brauner
The posix acl permission checking helpers determine whether a caller is privileged over an inode according to the acls associated with the inode. Add helpers that make it possible to handle acls on idmapped mounts. The vfs and the filesystems targeted by this first iteration make use of posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to translate basic posix access and default permissions such as the ACL_USER and ACL_GROUP type according to the initial user namespace (or the superblock's user namespace) to and from the caller's current user namespace. Adapt these two helpers to handle idmapped mounts whereby we either map from or into the mount's user namespace depending on in which direction we're translating. Similarly, cap_convert_nscap() is used by the vfs to translate user namespace and non-user namespace aware filesystem capabilities from the superblock's user namespace to the caller's user namespace. Enable it to handle idmapped mounts by accounting for the mount's user namespace. In addition the fileystems targeted in the first iteration of this patch series make use of the posix_acl_chmod() and, posix_acl_update_mode() helpers. Both helpers perform permission checks on the target inode. Let them handle idmapped mounts. These two helpers are called when posix acls are set by the respective filesystems to handle this case we extend the ->set() method to take an additional user namespace argument to pass the mount's user namespace down. Link: https://lore.kernel.org/r/20210121131959.646623-9-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-04afs: Fix directory entry size calculationDavid Howells
The number of dirent records used by an AFS directory entry should be calculated using the assumption that there is a 16-byte name field in the first block, rather than a 20-byte name field (which is actually the case). This miscalculation is historic and effectively standard, so we have to use it. The calculation we need to use is: 1 + (((strlen(name) + 1) + 15) >> 5) where we are adding one to the strlen() result to account for the NUL termination. Fix this by the following means: (1) Create an inline function to do the calculation for a given name length. (2) Use the function to calculate the number of records used for a dirent in afs_dir_iterate_block(). Use this to move the over-end check out of the loop since it only needs to be done once. Further use this to only go through the loop for the 2nd+ records composing an entry. The only test there now is for if the record is allocated - and we already checked the first block at the top of the outer loop. (3) Add a max name length check in afs_dir_iterate_block(). (4) Make afs_edit_dir_add() and afs_edit_dir_remove() use the function from (1) to calculate the number of blocks rather than doing it incorrectly themselves. Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...") Fixes: ^1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marc Dionne <marc.dionne@auristor.com>
2021-01-04afs: Work around strnlen() oops with CONFIG_FORTIFIED_SOURCE=yDavid Howells
AFS has a structured layout in its directory contents (AFS dirs are downloaded as files and parsed locally by the client for lookup/readdir). The slots in the directory are defined by union afs_xdr_dirent. This, however, only directly allows a name of a length that will fit into that union. To support a longer name, the next 1-8 contiguous entries are annexed to the first one and the name flows across these. afs_dir_iterate_block() uses strnlen(), limited to the space to the end of the page, to find out how long the name is. This worked fine until 6a39e62abbaf. With that commit, the compiler determines the size of the array and asserts that the string fits inside that array. This is a problem for AFS because we *expect* it to overflow one or more arrays. A similar problem also occurs in afs_dir_scan_block() when a directory file is being locally edited to avoid the need to redownload it. There strlen() was being used safely because each page has the last byte set to 0 when the file is downloaded and validated (in afs_dir_check_page()). Fix this by changing the afs_xdr_dirent union name field to an indeterminate-length array and dropping the overflow field. (Note that whilst looking at this, I realised that the calculation of the number of slots a dirent used is non-standard and not quite right, but I'll address that in a separate patch.) The issue can be triggered by something like: touch /afs/example.com/thisisaveryveryverylongname and it generates a report that looks like: detected buffer overflow in strnlen ------------[ cut here ]------------ kernel BUG at lib/string.c:1149! ... RIP: 0010:fortify_panic+0xf/0x11 ... Call Trace: afs_dir_iterate_block+0x12b/0x35b afs_dir_iterate+0x14e/0x1ce afs_do_lookup+0x131/0x417 afs_lookup+0x24f/0x344 lookup_open.isra.0+0x1bb/0x27d open_last_lookups+0x166/0x237 path_openat+0xe0/0x159 do_filp_open+0x48/0xa4 ? kmem_cache_alloc+0xf5/0x16e ? __clear_close_on_exec+0x13/0x22 ? _raw_spin_unlock+0xa/0xb do_sys_openat2+0x72/0xde do_sys_open+0x3b/0x58 do_syscall_64+0x2d/0x3a entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 6a39e62abbaf ("lib: string.h: detect intra-object overflow in fortified string functions") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marc Dionne <marc.dionne@auristor.com> cc: Daniel Axtens <dja@axtens.net>
2020-12-08afs: Fix memory leak when mounting with multiple source parametersDavid Howells
There's a memory leak in afs_parse_source() whereby multiple source= parameters overwrite fc->source in the fs_context struct without freeing the previously recorded source. Fix this by only permitting a single source parameter and rejecting with an error all subsequent ones. This was caught by syzbot with the kernel memory leak detector, showing something like the following trace: unreferenced object 0xffff888114375440 (size 32): comm "repro", pid 5168, jiffies 4294923723 (age 569.948s) backtrace: slab_post_alloc_hook+0x42/0x79 __kmalloc_track_caller+0x125/0x16a kmemdup_nul+0x24/0x3c vfs_parse_fs_string+0x5a/0xa1 generic_parse_monolithic+0x9d/0xc5 do_new_mount+0x10d/0x15a do_mount+0x5f/0x8e __do_sys_mount+0xff/0x127 do_syscall_64+0x2d/0x3a entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 13fcc6837049 ("afs: Add fs_context support") Reported-by: syzbot+86dc6632faaca40133ab@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-22afs: Fix speculative status fetch going out of order wrt to modificationsDavid Howells
When doing a lookup in a directory, the afs filesystem uses a bulk status fetch to speculatively retrieve the statuses of up to 48 other vnodes found in the same directory and it will then either update extant inodes or create new ones - effectively doing 'lookup ahead'. To avoid the possibility of deadlocking itself, however, the filesystem doesn't lock all of those inodes; rather just the directory inode is locked (by the VFS). When the operation completes, afs_inode_init_from_status() or afs_apply_status() is called, depending on whether the inode already exists, to commit the new status. A case exists, however, where the speculative status fetch operation may straddle a modification operation on one of those vnodes. What can then happen is that the speculative bulk status RPC retrieves the old status, and whilst that is happening, the modification happens - which returns an updated status, then the modification status is committed, then we attempt to commit the speculative status. This results in something like the following being seen in dmesg: kAFS: vnode modified {100058:861} 8->9 YFS.InlineBulkStatus showing that for vnode 861 on volume 100058, we saw YFS.InlineBulkStatus say that the vnode had data version 8 when we'd already recorded version 9 due to a local modification. This was causing the cache to be invalidated for that vnode when it shouldn't have been. If it happens on a data file, this might lead to local changes being lost. Fix this by ignoring speculative status updates if the data version doesn't match the expected value. Note that it is possible to get a DV regression if a volume gets restored from a backup - but we should get a callback break in such a case that should trigger a recheck anyway. It might be worth checking the volume creation time in the volsync info and, if a change is observed in that (as would happen on a restore), invalidate all caches associated with the volume. Fixes: 5cf9dd55a0ec ("afs: Prospectively look up extra files when doing a single lookup") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14afs: Fix afs_write_end() when called with copied == 0 [ver #3]David Howells
When afs_write_end() is called with copied == 0, it tries to set the dirty region, but there's no way to actually encode a 0-length region in the encoding in page->private. "0,0", for example, indicates a 1-byte region at offset 0. The maths miscalculates this and sets it incorrectly. Fix it to just do nothing but unlock and put the page in this case. We don't actually need to mark the page dirty as nothing presumably changed. Fixes: 65dd2d6072d3 ("afs: Alter dirty range encoding in page->private") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-03afs: Fix incorrect freeing of the ACL passed to the YFS ACL store opDavid Howells
The cleanup for the yfs_store_opaque_acl2_operation calls the wrong function to destroy the ACL content buffer. It's an afs_acl struct, not a yfs_acl struct - and the free function for latter may pass invalid pointers to kfree(). Fix this by using the afs_acl_put() function. The yfs_acl_put() function is then no longer used and can be removed. general protection fault, probably for non-canonical address 0x7ebde00000000: 0000 [#1] SMP PTI ... RIP: 0010:compound_head+0x0/0x11 ... Call Trace: virt_to_cache+0x8/0x51 kfree+0x5d/0x79 yfs_free_opaque_acl+0x16/0x29 afs_put_operation+0x60/0x114 __vfs_setxattr+0x67/0x72 __vfs_setxattr_noperm+0x66/0xe9 vfs_setxattr+0x67/0xce setxattr+0x14e/0x184 __do_sys_fsetxattr+0x66/0x8f do_syscall_64+0x2d/0x3a entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-03afs: Fix warning due to unadvanced marshalling pointerDavid Howells
When using the afs.yfs.acl xattr to change an AuriStor ACL, a warning can be generated when the request is marshalled because the buffer pointer isn't increased after adding the last element, thereby triggering the check at the end if the ACL wasn't empty. This just causes something like the following warning, but doesn't stop the call from happening successfully: kAFS: YFS.StoreOpaqueACL2: Request buffer underflow (36<108) Fix this simply by increasing the count prior to the check. Fixes: f5e4546347bc ("afs: Implement YFS ACL setting") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-29afs: Fix dirty-region encoding on ppc32 with 64K pagesDavid Howells
The dirty region bounds stored in page->private on an afs page are 15 bits on a 32-bit box and can, at most, represent a range of up to 32K within a 32K page with a resolution of 1 byte. This is a problem for powerpc32 with 64K pages enabled. Further, transparent huge pages may get up to 2M, which will be a problem for the afs filesystem on all 32-bit arches in the future. Fix this by decreasing the resolution. For the moment, a 64K page will have a resolution determined from PAGE_SIZE. In the future, the page will need to be passed in to the helper functions so that the page size can be assessed and the resolution determined dynamically. Note that this might not be the ideal way to handle this, since it may allow some leakage of undirtied zero bytes to the server's copy in the case of a 3rd-party conflict. Fixing that would require a separately allocated record and is a more complicated fix. Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-10-29afs: Fix afs_invalidatepage to adjust the dirty regionDavid Howells
Fix afs_invalidatepage() to adjust the dirty region recorded in page->private when truncating a page. If the dirty region is entirely removed, then the private data is cleared and the page dirty state is cleared. Without this, if the page is truncated and then expanded again by truncate, zeros from the expanded, but no-longer dirty region may get written back to the server if the page gets laundered due to a conflicting 3rd-party write. It mustn't, however, shorten the dirty region of the page if that page is still mmapped and has been marked dirty by afs_page_mkwrite(), so a flag is stored in page->private to record this. Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Alter dirty range encoding in page->privateDavid Howells
Currently, page->private on an afs page is used to store the range of dirtied data within the page, where the range includes the lower bound, but excludes the upper bound (e.g. 0-1 is a range covering a single byte). This, however, requires a superfluous bit for the last-byte bound so that on a 4KiB page, it can say 0-4096 to indicate the whole page, the idea being that having both numbers the same would indicate an empty range. This is unnecessary as the PG_private bit is clear if it's an empty range (as is PG_dirty). Alter the way the dirty range is encoded in page->private such that the upper bound is reduced by 1 (e.g. 0-0 is then specified the same single byte range mentioned above). Applying this to both bounds frees up two bits, one of which can be used in a future commit. This allows the afs filesystem to be compiled on ppc32 with 64K pages; without this, the following warnings are seen: ../fs/afs/internal.h: In function 'afs_page_dirty_to': ../fs/afs/internal.h:881:15: warning: right shift count >= width of type [-Wshift-count-overflow] 881 | return (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK; | ^~ ../fs/afs/internal.h: In function 'afs_page_dirty': ../fs/afs/internal.h:886:28: warning: left shift count >= width of type [-Wshift-count-overflow] 886 | return ((unsigned long)to << __AFS_PAGE_PRIV_SHIFT) | from; | ^~ Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Wrap page->private manipulations in inline functionsDavid Howells
The afs filesystem uses page->private to store the dirty range within a page such that in the event of a conflicting 3rd-party write to the server, we write back just the bits that got changed locally. However, there are a couple of problems with this: (1) I need a bit to note if the page might be mapped so that partial invalidation doesn't shrink the range. (2) There aren't necessarily sufficient bits to store the entire range of data altered (say it's a 32-bit system with 64KiB pages or transparent huge pages are in use). So wrap the accesses in inline functions so that future commits can change how this works. Also move them out of the tracing header into the in-directory header. There's not really any need for them to be in the tracing header. Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Fix where page->private is set during writeDavid Howells
In afs, page->private is set to indicate the dirty region of a page. This is done in afs_write_begin(), but that can't take account of whether the copy into the page actually worked. Fix this by moving the change of page->private into afs_write_end(). Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Fix page leak on afs_write_begin() failureDavid Howells
Fix the leak of the target page in afs_write_begin() when it fails. Fixes: 15b4650e55e0 ("afs: convert to new aops") Signed-off-by: David Howells <dhowells@redhat.com> cc: Nick Piggin <npiggin@gmail.com>
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