kernel/linux.git/fs/afs/write.c, branch v5.15.209

afs: Adjust ACK interpretation to try and cope with NAT

2022-06-09T08:22:40+00:00

[ Upstream commit adc9613ff66c26ebaff9814973181ac178beb90b ] If a client's address changes, say if it is NAT'd, this can disrupt an in progress operation. For most operations, this is not much of a problem, but StoreData can be different as some servers modify the target file as the data comes in, so if a store request is disrupted, the file can get corrupted on the server. The problem is that the server doesn't recognise packets that come after the change of address as belonging to the original client and will bounce them, either by sending an OUT_OF_SEQUENCE ACK to the apparent new call if the packet number falls within the initial sequence number window of a call or by sending an EXCEEDS_WINDOW ACK if it falls outside and then aborting it. In both cases, firstPacket will be 1 and previousPacket will be 0 in the ACK information. Fix this by the following means: (1) If a client call receives an EXCEEDS_WINDOW ACK with firstPacket as 1 and previousPacket as 0, assume this indicates that the server saw the incoming packets from a different peer and thus as a different call. Fail the call with error -ENETRESET. (2) Also fail the call if a similar OUT_OF_SEQUENCE ACK occurs if the first packet has been hard-ACK'd. If it hasn't been hard-ACK'd, the ACK packet will cause it to get retransmitted, so the call will just be repeated. (3) Make afs_select_fileserver() treat -ENETRESET as a straight fail of the operation. (4) Prioritise the error code over things like -ECONNRESET as the server did actually respond. (5) Make writeback treat -ENETRESET as a retryable error and make it redirty all the pages involved in a write so that the VM will retry. Note that there is still a circumstance that I can't easily deal with: if the operation is fully received and processed by the server, but the reply is lost due to address change. There's no way to know if the op happened. We can examine the server, but a conflicting change could have been made by a third party - and we can't tell the difference. In such a case, a message like: kAFS: vnode modified {100058:146266} b7->b8 YFS.StoreData64 (op=2646a) will be logged to dmesg on the next op to touch the file and the client will reset the inode state, including invalidating clean parts of the pagecache. Reported-by: Marc Dionne Signed-off-by: David Howells cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-December/004811.html # v1 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

afs: Fix afs_launder_page() to set correct start file position

2021-10-05T10:22:06+00:00

Fix afs_launder_page() to set the starting position of the StoreData RPC at the offset into the page at which the modified data starts instead of at the beginning of the page (the iov_iter is correctly offset). The offset got lost during the conversion to passing an iov_iter into afs_store_data(). Changes: ver #2: - Use page_offset() rather than manually calculating it[1]. Fixes: bd80d8a80e12 ("afs: Use ITER_XARRAY for writing") Signed-off-by: David Howells Reviewed-by: Jeffrey Altman cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YST/0e92OdSH0zjg@casper.infradead.org/ [1] Link: https://lore.kernel.org/r/162880783179.3421678.7795105718190440134.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162937512409.1449272.18441473411207824084.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162981148752.1901565.3663780601682206026.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163005741670.2472992.2073548908229887941.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163221839087.3143591.14278359695763025231.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163292980654.4004896.7134735179887998551.stgit@warthog.procyon.org.uk/ # v2

afs: Fix updating of i_blocks on file/dir extension

2021-09-13T08:14:21+00:00

When an afs file or directory is modified locally such that the total file size is extended, i_blocks needs to be recalculated too. Fix this by making afs_write_end() and afs_edit_dir_add() call afs_set_i_size() rather than setting inode->i_size directly as that also recalculates inode->i_blocks. This can be tested by creating and writing into directories and files and then examining them with du. Without this change, directories show a 4 blocks (they start out at 2048 bytes) and files show 0 blocks; with this change, they should show a number of blocks proportional to the file size rounded up to 1024. Fixes: 31143d5d515e ("AFS: implement basic file write support") Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...") Reported-by: Markus Suvanto Signed-off-by: David Howells Reviewed-by: Marc Dionne Tested-by: Markus Suvanto cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/163113612442.352844.11162345591911691150.stgit@warthog.procyon.org.uk/

afs: Add missing vnode validation checks

2021-09-13T08:10:39+00:00

afs_d_revalidate() should only be validating the directory entry it is given and the directory to which that belongs; it shouldn't be validating the inode/vnode to which that dentry points. Besides, validation need to be done even if we don't call afs_d_revalidate() - which might be the case if we're starting from a file descriptor. In order for afs_d_revalidate() to be fixed, validation points must be added in some other places. Certain directory operations, such as afs_unlink(), already check this, but not all and not all file operations either. Note that the validation of a vnode not only checks to see if the attributes we have are correct, but also gets a promise from the server to notify us if that file gets changed by a third party. Add the following checks: - Check the vnode we're going to make a hard link to. - Check the vnode we're going to move/rename. - Check the vnode we're going to read from. - Check the vnode we're going to write to. - Check the vnode we're going to sync. - Check the vnode we're going to make a mapped page writable for. Some of these aren't strictly necessary as we're going to perform a server operation that might get the attributes anyway from which we can determine if something changed - though it might not get us a callback promise. Signed-off-by: David Howells Tested-by: Markus Suvanto cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/163111667354.283156.12720698333342917516.stgit@warthog.procyon.org.uk/

afs: Fix page leak

2021-09-10T21:14:51+00:00

There's a loop in afs_extend_writeback() that adds extra pages to a write we want to make to improve the efficiency of the writeback by making it larger. This loop stops, however, if we hit a page we can't write back from immediately, but it doesn't get rid of the page ref we speculatively acquired. This was caused by the removal of the cleanup loop when the code switched from using find_get_pages_contig() to xarray scanning as the latter only gets a single page at a time, not a batch. Fix this by putting the page on a ref on an early break from the loop. Unfortunately, we can't just add that page to the pagevec we're employing as we'll go through that and add those pages to the RPC call. This was found by the generic/074 test. It leaks ~4GiB of RAM each time it is run - which can be observed with "top". Fixes: e87b03f5830e ("afs: Prepare for use of THPs") Reported-by: Marc Dionne Signed-off-by: David Howells Reviewed-and-tested-by: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/163111666635.283156.177701903478910460.stgit@warthog.procyon.org.uk/

afs: Fix setting of writeback_index

2021-07-21T14:10:23+00:00

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 Signed-off-by: David Howells Reviewed-by: Marc Dionne 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)

afs: check function return

2021-07-21T14:10:23+00:00

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 Signed-off-by: David Howells Reviewed-by: Marc Dionne 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

Merge tag 'netfs-fixes-20210621' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2021-06-25T16:41:29+00:00

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

afs: Fix afs_write_end() to handle short writes

2021-06-21T20:23:36+00:00

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 Signed-off-by: David Howells Acked-by: Jeff Layton Reviewed-by: Matthew Wilcox (Oracle) cc: Al Viro 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

afs: Re-enable freezing once a page fault is interrupted

2021-06-18T20:49:07+00:00

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) Signed-off-by: David Howells cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20210616154900.1958373-1-willy@infradead.org/ Signed-off-by: Linus Torvalds