- Jun 07, 2021
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Marc Dionne authored
In commit e87b03f5 ("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: e87b03f5 ("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>
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- May 27, 2021
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David Howells authored
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: e49c7b2f ("afs: Build an abstraction around an "operation" concept") Signed-off-by:
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- May 25, 2021
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Gustavo A. R. Silva authored
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:
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- May 01, 2021
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David Howells authored
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: a9e5c87c ("afs: Fix speculative status fetch going out of order wrt to modifications") Reported-by:
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- Apr 23, 2021
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
Extract writeback extension into its own function to break up the writeback function a bit. Signed-off-by:
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
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 authored
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:
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
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:
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David Howells authored
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:
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- Mar 23, 2021
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Matthew Wilcox (Oracle) authored
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: 1cf7a151 ("afs: Implement shared-writeable mmap") Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-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]
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- Mar 15, 2021
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David Howells authored
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: ae46578b ("afs: Get YFS ACLs and information through xattrs") Reported-by:
Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Signed-off-by:
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David Howells authored
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: e49c7b2f ("afs: Build an abstraction around an "operation" concept") Reported-by:
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- Mar 08, 2021
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David Howells authored
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: 260a9803 ("[AFS]: Add "directory write" support.") Reported-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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- Jan 30, 2021
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David Howells authored
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: 5271953c ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by:
Jakub Kicinski <kuba@kernel.org>
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- Jan 24, 2021
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Christian Brauner authored
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:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
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:
James Morris <jamorris@linux.microsoft.com> Signed-off-by:
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Christian Brauner authored
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:
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- Jan 04, 2021
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David Howells authored
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: 63a4681f ("afs: Locally edit directory data for mkdir/create/unlink/...") Fixes: ^1da177e4 ("Linux-2.6.12-rc2") Signed-off-by: -
David Howells authored
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 6a39e62a. 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: 6a39e62a ("lib: string.h: detect intra-object overflow in fortified string functions") Reported-by:
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- Dec 08, 2020
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David Howells authored
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: 13fcc683 ("afs: Add fs_context support") Reported-by:<syzbot+86dc6632faaca40133ab@syzkaller.appspotmail.com> Signed-off-by:
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- Nov 22, 2020
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David Howells authored
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: 5cf9dd55 ("afs: Prospectively look up extra files when doing a single lookup") Signed-off-by:
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- Nov 14, 2020
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David Howells authored
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: 65dd2d60 ("afs: Alter dirty range encoding in page->private") Signed-off-by:
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- Nov 03, 2020
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David Howells authored
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: e49c7b2f ("afs: Build an abstraction around an "operation" concept") Signed-off-by:
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David Howells authored
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: f5e45463 ("afs: Implement YFS ACL setting") Signed-off-by:
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- Oct 29, 2020
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David Howells authored
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: 4343d008 ("afs: Get rid of the afs_writeback record") Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
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David Howells authored
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: 4343d008 ("afs: Get rid of the afs_writeback record") Signed-off-by:
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David Howells authored
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: 4343d008 ("afs: Get rid of the afs_writeback record") Signed-off-by: -
David Howells authored
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 authored
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: 4343d008 ("afs: Get rid of the afs_writeback record") Signed-off-by:
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David Howells authored
Fix the leak of the target page in afs_write_begin() when it fails. Fixes: 15b4650e ("afs: convert to new aops") Signed-off-by:
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David Howells authored
Fix afs to take a ref on a page when it sets PG_private on it and to drop the ref when removing the flag. Note that in afs_write_begin(), a lot of the time, PG_private is already set on a page to which we're going to add some data. In such a case, we leave the bit set and mustn't increment the page count. As suggested by Matthew Wilcox, use attach/detach_page_private() where possible. Fixes: 31143d5d ("AFS: implement basic file write support") Reported-by:
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