kernel/linux.git/fs/afs/file.c, branch v6.12.80

afs: Fix missing wire-up of afs_retry_request()

2024-09-27T16:29:19+00:00

afs_retry_request() is supposed to be pointed to by the afs_req_ops netfs operations table, but the pointer got lost somewhere. The function is used during writeback to rotate through the authentication keys that were in force when the file was modified locally. Fix this by adding the pointer to the function. Fixes: 1ecb146f7cd8 ("netfs, afs: Use writeback retry to deal with alternate keys") Reported-by: Dr. David Alan Gilbert Signed-off-by: David Howells Link: https://lore.kernel.org/r/1690847.1726346402@warthog.procyon.org.uk cc: Marc Dionne cc: Jeff Layton cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner

netfs: Speed up buffered reading

2024-09-12T10:20:41+00:00

Improve the efficiency of buffered reads in a number of ways: (1) Overhaul the algorithm in general so that it's a lot more compact and split the read submission code between buffered and unbuffered versions. The unbuffered version can be vastly simplified. (2) Read-result collection is handed off to a work queue rather than being done in the I/O thread. Multiple subrequests can be processes simultaneously. (3) When a subrequest is collected, any folios it fully spans are collected and "spare" data on either side is donated to either the previous or the next subrequest in the sequence. Notes: (*) Readahead expansion is massively slows down fio, presumably because it causes a load of extra allocations, both folio and xarray, up front before RPC requests can be transmitted. (*) RDMA with cifs does appear to work, both with SIW and RXE. (*) PG_private_2-based reading and copy-to-cache is split out into its own file and altered to use folio_queue. Note that the copy to the cache now creates a new write transaction against the cache and adds the folios to be copied into it. This allows it to use part of the writeback I/O code. Signed-off-by: David Howells cc: Jeff Layton cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20240814203850.2240469-20-dhowells@redhat.com/ # v2 Signed-off-by: Christian Brauner

afs: Make read subreqs async

2024-09-12T10:20:40+00:00

Perform AFS read subrequests in a work item rather than in the calling thread. For normal buffered reads, this will allow the calling thread to copy data from the pagecache to the application at the same time as the demarshalling thread is shovelling data from skbuffs into the pagecache. This will also allow the RA mark to trigger a new read before we've finished shovelling the data from the current one. Note: This would be a bit safer if the FS.FetchData RPC ops returned the metadata (including the data version number) before returning the data. This would allow me to flush the pagecache before installing the new data. In future, it may be possible to asynchronously flush the pagecache either side of the region being read. Signed-off-by: David Howells cc: Marc Dionne cc: Jeff Layton cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20240814203850.2240469-19-dhowells@redhat.com/ # v2 Signed-off-by: Christian Brauner

9p: Fix DIO read through netfs

2024-08-13T11:53:09+00:00

If a program is watching a file on a 9p mount, it won't see any change in size if the file being exported by the server is changed directly in the source filesystem, presumably because 9p doesn't have change notifications, and because netfs skips the reads if the file is empty. Fix this by attempting to read the full size specified when a DIO read is requested (such as when 9p is operating in unbuffered mode) and dealing with a short read if the EOF was less than the expected read. To make this work, filesystems using netfslib must not set NETFS_SREQ_CLEAR_TAIL if performing a DIO read where that read hit the EOF. I don't want to mandatorily clear this flag in netfslib for DIO because, say, ceph might make a read from an object that is not completely filled, but does not reside at the end of file - and so we need to clear the excess. This can be tested by watching an empty file over 9p within a VM (such as in the ktest framework): while true; do read content; if [ -n "$content" ]; then echo $content; break; fi; done < /host/tmp/foo then writing something into the empty file. The watcher should immediately display the file content and break out of the loop. Without this fix, it remains in the loop indefinitely. Fixes: 80105ed2fd27 ("9p: Use netfslib read/write_iter") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218916 Signed-off-by: David Howells Link: https://lore.kernel.org/r/1229195.1723211769@warthog.procyon.org.uk cc: Eric Van Hensbergen cc: Latchesar Ionkov cc: Christian Schoenebeck cc: Marc Dionne cc: Ilya Dryomov cc: Steve French cc: Paulo Alcantara cc: Trond Myklebust cc: v9fs@lists.linux.dev cc: linux-afs@lists.infradead.org cc: ceph-devel@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Dominique Martinet Signed-off-by: Christian Brauner

netfs, afs: Use writeback retry to deal with alternate keys

2024-05-01T17:07:38+00:00

Use a hook in the new writeback code's retry algorithm to rotate the keys once all the outstanding subreqs have failed rather than doing it separately on each subreq. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org

netfs: Cut over to using new writeback code

2024-05-01T17:07:37+00:00

Cut over to using the new writeback code. The old code is #ifdef'd out or otherwise removed from compilation to avoid conflicts and will be removed in a future patch. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Eric Van Hensbergen cc: Latchesar Ionkov cc: Dominique Martinet cc: Christian Schoenebeck cc: Marc Dionne cc: v9fs@lists.linux.dev cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org

netfs, afs: Implement helpers for new write code

2024-05-01T17:07:36+00:00

Implement the helpers for the new write code in afs. There's now an optional ->prepare_write() that allows the filesystem to set the parameters for the next write, such as maximum size and maximum segment count, and an ->issue_write() that is called to initiate an (asynchronous) write operation. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org

afs: Use alternative invalidation to using launder_folio

2024-05-01T17:07:34+00:00

Use writepages-based flushing invalidation instead of invalidate_inode_pages2() and ->launder_folio(). This will allow ->launder_folio() to be removed eventually. Signed-off-by: David Howells cc: Marc Dionne cc: Jeff Layton cc: linux-afs@lists.infradead.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org

afs: fix __afs_break_callback() / afs_drop_open_mmap() race

2024-02-25T07:10:31+00:00

In __afs_break_callback() we might check ->cb_nr_mmap and if it's non-zero do queue_work(&vnode->cb_work). In afs_drop_open_mmap() we decrement ->cb_nr_mmap and do flush_work(&vnode->cb_work) if it reaches zero. The trouble is, there's nothing to prevent __afs_break_callback() from seeing ->cb_nr_mmap before the decrement and do queue_work() after both the decrement and flush_work(). If that happens, we might be in trouble - vnode might get freed before the queued work runs. __afs_break_callback() is always done under ->cb_lock, so let's make sure that ->cb_nr_mmap can change from non-zero to zero while holding ->cb_lock (the spinlock component of it - it's a seqlock and we don't need to mess with the counter). Acked-by: Christian Brauner Signed-off-by: Al Viro

Merge tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

2024-01-19T17:10:23+00:00

Pull netfs updates from Christian Brauner: "This extends the netfs helper library that network filesystems can use to replace their own implementations. Both afs and 9p are ported. cifs is ready as well but the patches are way bigger and will be routed separately once this is merged. That will remove lots of code as well. The overal goal is to get high-level I/O and knowledge of the page cache and ouf of the filesystem drivers. This includes knowledge about the existence of pages and folios The pull request converts afs and 9p. This removes about 800 lines of code from afs and 300 from 9p. For 9p it is now possible to do writes in larger than a page chunks. Additionally, multipage folio support can be turned on for 9p. Separate patches exist for cifs removing another 2000+ lines. I've included detailed information in the individual pulls I took. Summary: - Add NFS-style (and Ceph-style) locking around DIO vs buffered I/O calls to prevent these from happening at the same time. - Support for direct and unbuffered I/O. - Support for write-through caching in the page cache. - O_*SYNC and RWF_*SYNC writes use write-through rather than writing to the page cache and then flushing afterwards. - Support for write-streaming. - Support for write grouping. - Skip reads for which the server could only return zeros or EOF. - The fscache module is now part of the netfs library and the corresponding maintainer entry is updated. - Some helpers from the fscache subsystem are renamed to mark them as belonging to the netfs library. - Follow-up fixes for the netfs library. - Follow-up fixes for the 9p conversion" * tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (50 commits) netfs: Fix wrong #ifdef hiding wait cachefiles: Fix signed/unsigned mixup netfs: Fix the loop that unmarks folios after writing to the cache netfs: Fix interaction between write-streaming and cachefiles culling netfs: Count DIO writes netfs: Mark netfs_unbuffered_write_iter_locked() static netfs: Fix proc/fs/fscache symlink to point to "netfs" not "../netfs" netfs: Rearrange netfs_io_subrequest to put request pointer first 9p: Use length of data written to the server in preference to error 9p: Do a couple of cleanups 9p: Fix initialisation of netfs_inode for 9p cachefiles: Fix __cachefiles_prepare_write() 9p: Use netfslib read/write_iter afs: Use the netfs write helpers netfs: Export the netfs_sreq tracepoint netfs: Optimise away reads above the point at which there can be no data netfs: Implement a write-through caching option netfs: Provide a launder_folio implementation netfs: Provide a writepages implementation netfs, cachefiles: Pass upper bound length to allow expansion ...