This v10 patchset addresses at least some of Trond's latest concerns. Some of the feedback like the unlock_page() wrapper function in nfs_read_completion() I don't know how to address without an ifdef. Other feedback I'm not quite sure about splitting out netfs bits or what you would like to see. Trond I do not want to in any way ignore or miss any of your feedback so please elaborate as needed. This patchset converts NFS with fscache non-direct READ IO paths to use the netfs API with a non-invasive approach. The existing NFS pgio layer does not need extensive changes, and is the best way so far I've found to address Trond's concerns about modifying the IO path [1] as well as only enabling netfs when fscache is configured and enabled [2]. I have not attempted performance comparisions to address Chuck Lever's concern [3] because we are not converting the non-fscache enabled NFS IO paths to netfs. The patchset is based on 6.1-rc3 and has been pushed to github at: https://github.com/DaveWysochanskiRH/kernel/commits/nfs-fscache-netfs https://github.com/DaveWysochanskiRH/kernel/commit/bff09aa979010f38a11a6f92451e85d04d850715 Changes since v9 [7] ==================== PATCH1: Rename nfs_pageio_add_page to nfs_read_add_page (Trond) PATCH3: Remove a few #ifdef's and replace with wrappers (Trond) [8] PATCH6: RFC patch to reduce increase in nfs_inode memory footprint when netfs is configured but not enabled (Trond) [9] Testing ======= I did not do much testing on this as the changes to patches 1 and 3 are cosmetic. Patch #6 is RFC patch and may change, so if that is added it may need more testing. Known issues ============ 1. Unit test setting rsize < readahead does not properly read from fscache but re-reads data from the NFS server * This will be fixed with another linux-cachefs [4] patch to resolve "Stop read optimisation when folio removed from pagecache" * Daire Byrne also verified the patch fixes his issue as well 2. "Cache volume key already in use" after xfstest runs * xfstests (hammerspace with vers=4.2,fsc) shows the following on the console after some tests: "NFS: Cache volume key already in use (nfs,4.1,2,c50,cfe0100a,3,,,8000,100000,100000,bb8,ea60,7530,ea60,1)" * This may be fixed with another patch [5] that is in progress 3. Daire Byrne reported a NULL pointer oops at cachefiles_prepare_write+0x28/0x90 * harder to reproduce/debug but under investigation [6] * only reproduced on RHEL7.9 based NFS re-export server using fscache with upstream kernel plus the previous patches * Debug in progress, first pass at where the problem is indicates a race between fscache cookie LRU and use_cookie; looking at cookie state machine [10] [58710.346376] BUG: kernel NULL pointer dereference, address: 0000000000000008 [58710.371212] CPU: 12 PID: 9134 Comm: kworker/u129:0 Tainted: G E 6.0.0-2.dneg.x86_64 #1 ... [58710.389995] Workqueue: events_unbound netfs_rreq_write_to_cache_work [netfs] [58710.397188] RIP: 0010:cachefiles_prepare_write+0x28/0x90 [cachefiles] ... [58710.500316] Call Trace: [58710.502894] <TASK> [58710.505126] netfs_rreq_write_to_cache_work+0x11c/0x320 [netfs] [58710.511201] process_one_work+0x217/0x3e0 [58710.515358] worker_thread+0x4a/0x3b0 [58710.519152] ? process_one_work+0x3e0/0x3e0 [58710.523467] kthread+0xd6/0x100 [58710.526740] ? kthread_complete_and_exit+0x20/0x20 [58710.531659] ret_from_fork+0x1f/0x30 References ========== [1] https://lore.kernel.org/linux-nfs/9cfd5bc3cfc6abc2d3316b0387222e708d67f595.camel@xxxxxxxxxxxxxxx/ [2] https://lore.kernel.org/linux-nfs/da9200f1bded9b8b078a7aef227fd6b92eb028fb.camel@xxxxxxxxxxxxxxx/ [3] https://marc.info/?l=linux-nfs&m=160597917525083&w=4 [4] https://www.mail-archive.com/linux-cachefs@xxxxxxxxxx/msg03043.html [5] https://marc.info/?l=linux-nfs&m=165962662200679&w=4 [6] https://listman.redhat.com/archives/linux-cachefs/2022-September/007183.html [7] https://marc.info/?l=linux-nfs&m=166600357429305&w=4 [8] https://marc.info/?l=linux-nfs&m=166697599503342&w=4 [9] https://marc.info/?l=linux-nfs&m=166717208305834&w=4 [10] https://listman.redhat.com/archives/linux-cachefs/2022-October/007259.html Dave Wysochanski (5): NFS: Rename readpage_async_filler to nfs_pageio_add_page NFS: Configure support for netfs when NFS fscache is configured NFS: Convert buffered read paths to use netfs when fscache is enabled NFS: Remove all NFSIOS_FSCACHE counters due to conversion to netfs API NFS: Remove fscache specific trace points and NFS_INO_FSCACHE bit fs/nfs/Kconfig | 1 + fs/nfs/delegation.c | 2 +- fs/nfs/dir.c | 2 +- fs/nfs/fscache.c | 242 ++++++++++++++++++++++--------------- fs/nfs/fscache.h | 111 +++++++++++------ fs/nfs/inode.c | 8 +- fs/nfs/internal.h | 11 +- fs/nfs/iostat.h | 17 --- fs/nfs/nfstrace.h | 91 -------------- fs/nfs/pagelist.c | 12 ++ fs/nfs/pnfs.c | 12 +- fs/nfs/read.c | 110 +++++++++-------- fs/nfs/super.c | 11 -- fs/nfs/write.c | 2 +- include/linux/nfs_fs.h | 35 ++++-- include/linux/nfs_iostat.h | 12 -- include/linux/nfs_page.h | 3 + include/linux/nfs_xdr.h | 3 + 18 files changed, 335 insertions(+), 350 deletions(-) -- 2.31.1 *** BLURB HERE *** Dave Wysochanski (6): NFS: Rename readpage_async_filler to nfs_read_add_page NFS: Configure support for netfs when NFS fscache is configured NFS: Convert buffered read paths to use netfs when fscache is enabled NFS: Remove all NFSIOS_FSCACHE counters due to conversion to netfs API NFS: Remove fscache specific trace points and NFS_INO_FSCACHE bit netfs: Change netfs_inode_init to allocate memory to allow opt-in fs/9p/cache.c | 2 +- fs/9p/vfs_inode.c | 17 ++- fs/afs/dynroot.c | 7 +- fs/afs/inode.c | 14 +-- fs/afs/internal.h | 2 +- fs/afs/super.c | 7 ++ fs/afs/write.c | 2 +- fs/ceph/inode.c | 6 +- fs/netfs/buffered_read.c | 16 +-- fs/netfs/internal.h | 2 +- fs/netfs/objects.c | 2 +- fs/nfs/Kconfig | 1 + fs/nfs/delegation.c | 2 +- fs/nfs/dir.c | 2 +- fs/nfs/fscache.c | 242 ++++++++++++++++++++++--------------- fs/nfs/fscache.h | 136 +++++++++++++++------ fs/nfs/inode.c | 15 ++- fs/nfs/internal.h | 11 +- fs/nfs/iostat.h | 17 --- fs/nfs/nfstrace.h | 91 -------------- fs/nfs/pagelist.c | 4 + fs/nfs/pnfs.c | 12 +- fs/nfs/read.c | 110 +++++++++-------- fs/nfs/super.c | 11 -- fs/nfs/write.c | 2 +- include/linux/netfs.h | 41 +++++-- include/linux/nfs_fs.h | 35 ++++-- include/linux/nfs_iostat.h | 12 -- include/linux/nfs_page.h | 3 + include/linux/nfs_xdr.h | 3 + 30 files changed, 428 insertions(+), 399 deletions(-) -- 2.31.1
