From patchwork Tue Nov 12 17:55:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Josef Bacik X-Patchwork-Id: 13872707 Received: from mail-yw1-f173.google.com (mail-yw1-f173.google.com [209.85.128.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9AC78215007 for ; Tue, 12 Nov 2024 17:56:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731434191; cv=none; b=HSkj+z6Y3S/aNeOD1oRFAF7ki0O3ucTzXB3HcF2kyjGxaHezMbbde/KxKoFz2i82ccEm36WDR5Af2AI6pWCjcuKMwRBZ8caSjUStshRjaX5//S+RMUVIUuqmBoXxB4UhYxmM6TS/+3LO+/HxbQ6PwVaBqnnhSU6kWPjkt7bLu5U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731434191; c=relaxed/simple; bh=esdaILa7AKbxpOU9tYwViCla+kycTwZVmfRFoeCuTbc=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=KD6lxSFTglJLkNFew79alftbqB+AbCWIV40PwMzzDqGoeegwC9abbwcELKuiFA8AULAXwK+5NspnOp89PWRLhY2ZnW0dnxFEgafucn1+/xHqDGMipJRSOOWTaBaSVqjejomcFAFhVFTxxJgyXLPLPd0U3KbawW3kohUyhoUK+tY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=toxicpanda.com; spf=none smtp.mailfrom=toxicpanda.com; dkim=pass (2048-bit key) header.d=toxicpanda-com.20230601.gappssmtp.com header.i=@toxicpanda-com.20230601.gappssmtp.com header.b=jXJjs3/J; arc=none smtp.client-ip=209.85.128.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=toxicpanda.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=toxicpanda.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=toxicpanda-com.20230601.gappssmtp.com header.i=@toxicpanda-com.20230601.gappssmtp.com header.b="jXJjs3/J" Received: by mail-yw1-f173.google.com with SMTP id 00721157ae682-6e9f8dec3daso46169917b3.0 for ; Tue, 12 Nov 2024 09:56:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda-com.20230601.gappssmtp.com; s=20230601; t=1731434187; x=1732038987; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date:message-id:reply-to; bh=g48wmOGZabKsmMEfPaYhGe4dtOd9ozHYTrWY8XD5r2k=; b=jXJjs3/JH2+IHUofpAGDd/ER77BXeXxFTIaFQ2KZI/fccpVkpLuwAv/Rfrf7rze+Ls qkUQoIkYC1B6mUCDwp0AFMjgvyAwVZl/Sd4exzZaP5GwRqVLQawWIdj/FFp12OTB24bi QW2R+zCla6MKFz3j8yh6PxubErEDbAIsCDffxF9EpNeKpcIwfK/kOcJq8wgCtrTM8Ifx SndTZGOPpZUWM3WmhAcBeUGPMjidpq4LFotZ2RkX2LioHr0Qrn7dJXhCzBtJaqb5RUqh RPYmf5F8UVIqhpbZmRiSPZLrxXKK2nSsXQb1YTe80NJ0ZZqLs9Er8sCIhugET0rUIgJa K9yQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731434187; x=1732038987; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=g48wmOGZabKsmMEfPaYhGe4dtOd9ozHYTrWY8XD5r2k=; b=SrDzhiiT/i/pjdXBa82OQK40dOlQ4+Kq/DsiyVymohnt2WvivN72OKcq9TALbPHaC1 D0Rq9uAR84v4aGRqaIzgExr0nS1/qa1EGpUOPSiaLNoLWC/VPpMtkwi9nH1OudUwWObN AlSQz6KC7pKXyq6YhDyKkf2l2dh8aDXi/caawfigc1u4nq14ey0vLZQ2xEYdp5nn6ylJ LUEbTnPHDmewHkuJn3pvTDy2t2dlbsRVlnfsj877I5bAmbzkeTFIj5+UWvnLc5icxnYS M+QAMiDfO868OC3yRPmX00Nqas02RqF7ITFwfcsEswg3OaIDISBq6WmdkrG93hmiVhC6 PNow== X-Forwarded-Encrypted: i=1; AJvYcCXxx9bllGq6WsAkedIUvnNVRXe2lUjq4Txm/Zs1gLh80zHgEH7B+aela0XB+JeHxzPWWPlor6t0dnREVB1u@vger.kernel.org X-Gm-Message-State: AOJu0YwfVsF0VULzEerr7GNEO2hsOMlr1Ue7gYYowkJDiPDDhZUDJVCB qlXsXH3LX+0xT2pt5e3lmg5zii3Ug9vIChRBGw1zC78FOKvuU27A/n9GsI4WZ9k= X-Google-Smtp-Source: AGHT+IGENyk2mAziIYhZQg41cfzA0HPYUllNcDo1wflc5oTm5yw6vvf+phT1j0QUEo4365Asvd+k2g== X-Received: by 2002:a05:690c:6f92:b0:6ea:8556:1cd6 with SMTP id 00721157ae682-6eaddf84222mr180166387b3.30.1731434187543; Tue, 12 Nov 2024 09:56:27 -0800 (PST) Received: from localhost (syn-076-182-020-124.res.spectrum.com. [76.182.20.124]) by smtp.gmail.com with ESMTPSA id 00721157ae682-6eaceb7b34fsm26786047b3.115.2024.11.12.09.56.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Nov 2024 09:56:26 -0800 (PST) From: Josef Bacik To: kernel-team@fb.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, amir73il@gmail.com, brauner@kernel.org, torvalds@linux-foundation.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-ext4@vger.kernel.org Subject: [PATCH v7 00/18] fanotify: add pre-content hooks Date: Tue, 12 Nov 2024 12:55:15 -0500 Message-ID: X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 v6: https://lore.kernel.org/linux-fsdevel/cover.1731355931.git.josef@toxicpanda.com/ v5: https://lore.kernel.org/linux-fsdevel/cover.1725481503.git.josef@toxicpanda.com/ v4: https://lore.kernel.org/linux-fsdevel/cover.1723670362.git.josef@toxicpanda.com/ v3: https://lore.kernel.org/linux-fsdevel/cover.1723228772.git.josef@toxicpanda.com/ v2: https://lore.kernel.org/linux-fsdevel/cover.1723144881.git.josef@toxicpanda.com/ v1: https://lore.kernel.org/linux-fsdevel/cover.1721931241.git.josef@toxicpanda.com/ v6->v7: - As per Linus's suggestion, Amir added the file flag FMODE_NOTIFY_PERM that will be set at open time if the file has permission related watches (this is the original malware style permission watches and the new precontent watches). All of the VFS hooks and the page fault hooks use this flag to determine if they should generate a notification to allow for a much cheaper check in the common case. v5->v6: - Linus had problems with this and rejected Jan's PR (https://lore.kernel.org/linux-fsdevel/20240923110348.tbwihs42dxxltabc@quack3/), so I'm respinning this series to address his concerns. Hopefully this is more acceptable. - Change the page fault hooks to happen only in the case where we have to add a page, not where there exists pages already. - Amir added a hook to truncate. - We made the flag per SB instead of per fstype, Amir wanted this because of some potential issues with other file system specific work he's doing. - Dropped the bcachefs patch, there were some concerns that we were doing something wrong, and it's not a huge deal to not have this feature for now. - Unfortunately the xfs write fault path still has to do the page fault hook before we know if we have a page or not, this is because of the locking that's done before we get to the part where we know if we have a page already or not, so that's the path that is still the same from last iteration. - I've re-validated this series with btrfs, xfs, and ext4 to make sure I didn't break anything. v4->v5: - Cleaned up the various "I'll fix it on commit" notes that Jan made since I had to respin the series anyway. - Renamed the filemap pagefault helper for fsnotify per Christians suggestion. - Added a FS_ALLOW_HSM flag per Jan's comments, based on Amir's rough sketch. - Added a patch to disable btrfs defrag on pre-content watched files. - Added a patch to turn on FS_ALLOW_HSM for all the file systems that I tested. - Added two fstests (which will be posted separately) to validate everything, re-validated the series with btrfs, xfs, ext4, and bcachefs to make sure I didn't break anything. v3->v4: - Trying to send a final verson Friday at 5pm before you go on vacation is a recipe for silly mistakes, fixed the xfs handling yet again, per Christoph's review. - Reworked the file system helper so it's handling of fpin was a little less silly, per Chinner's suggestion. - Updated the return values to not or in VM_FAULT_RETRY, as we have a comment in filemap_fault that says if VM_FAULT_ERROR is set we won't have VM_FAULT_RETRY set. v2->v3: - Fix the pagefault path to do MAY_ACCESS instead, updated the perm handler to emit PRE_ACCESS in this case, so we can avoid the extraneous perm event as per Amir's suggestion. - Reworked the exported helper so the per-filesystem changes are much smaller, per Amir's suggestion. - Fixed the screwup for DAX writes per Chinner's suggestion. - Added Christian's reviewed-by's where appropriate. v1->v2: - reworked the page fault logic based on Jan's suggestion and turned it into a helper. - Added 3 patches per-fs where we need to call the fsnotify helper from their ->fault handlers. - Disabled readahead in the case that there's a pre-content watch in place. - Disabled huge faults when there's a pre-content watch in place (entirely because it's untested, theoretically it should be straightforward to do). - Updated the command numbers. - Addressed the random spelling/grammer mistakes that Jan pointed out. - Addressed the other random nits from Jan. --- Original email --- Hello, These are the patches for the bare bones pre-content fanotify support. The majority of this work is Amir's, my contribution to this has solely been around adding the page fault hooks, testing and validating everything. I'm sending it because Amir is traveling a bunch, and I touched it last so I'm going to take all the hate and he can take all the credit. There is a PoC that I've been using to validate this work, you can find the git repo here https://github.com/josefbacik/remote-fetch This consists of 3 different tools. 1. populate. This just creates all the stub files in the directory from the source directory. Just run ./populate ~/linux ~/hsm-linux and it'll recursively create all of the stub files and directories. 2. remote-fetch. This is the actual PoC, you just point it at the source and destination directory and then you can do whatever. ./remote-fetch ~/linux ~/hsm-linux. 3. mmap-validate. This was to validate the pagefault thing, this is likely what will be turned into the selftest with remote-fetch. It creates a file and then you can validate the file matches the right pattern with both normal reads and mmap. Normally I do something like ./mmap-validate create ~/src/foo ./populate ~/src ~/dst ./rmeote-fetch ~/src ~/dst ./mmap-validate validate ~/dst/foo I did a bunch of testing, I also got some performance numbers. I copied a kernel tree, and then did remote-fetch, and then make -j4 Normal real 9m49.709s user 28m11.372s sys 4m57.304s HSM real 10m6.454s user 29m10.517s sys 5m2.617s So ~17 seconds more to build with HSM. I then did a make mrproper on both trees to see the size [root@fedora ~]# du -hs /src/linux 1.6G /src/linux [root@fedora ~]# du -hs dst 125M dst This mirrors the sort of savings we've seen in production. Meta has had these patches (minus the page fault patch) deployed in production for almost a year with our own utility for doing on-demand package fetching. The savings from this has been pretty significant. The page-fault hooks are necessary for the last thing we need, which is on-demand range fetching of executables. Some of our binaries are several gigs large, having the ability to remote fetch them on demand is a huge win for us not only with space savings, but with startup time of containers. There will be tests for this going into LTP once we're satisfied with the patches and they're on their way upstream. Thanks, Josef Amir Goldstein (11): fsnotify: opt-in for permission events at file_open_perm() time fanotify: don't skip extra event info if no info_mode is set fanotify: rename a misnamed constant fanotify: reserve event bit of deprecated FAN_DIR_MODIFY fsnotify: introduce pre-content permission events fsnotify: pass optional file access range in pre-content event fsnotify: generate pre-content permission event on open fsnotify: generate pre-content permission event on truncate fanotify: introduce FAN_PRE_ACCESS permission event fanotify: report file range info with pre-content events fanotify: allow to set errno in FAN_DENY permission response Josef Bacik (7): fanotify: add a helper to check for pre content events fanotify: disable readahead if we have pre-content watches mm: don't allow huge faults for files with pre content watches fsnotify: generate pre-content permission event on page fault xfs: add pre-content fsnotify hook for write faults btrfs: disable defrag on pre-content watched files fs: enable pre-content events on supported file systems fs/btrfs/ioctl.c | 9 +++ fs/btrfs/super.c | 2 +- fs/ext4/super.c | 3 + fs/namei.c | 10 ++- fs/notify/fanotify/fanotify.c | 33 ++++++-- fs/notify/fanotify/fanotify.h | 15 ++++ fs/notify/fanotify/fanotify_user.c | 120 +++++++++++++++++++++++------ fs/notify/fsnotify.c | 14 +++- fs/open.c | 31 +++++--- fs/xfs/xfs_file.c | 4 + fs/xfs/xfs_super.c | 2 +- include/linux/fanotify.h | 19 +++-- include/linux/fs.h | 4 +- include/linux/fsnotify.h | 120 ++++++++++++++++++++++++----- include/linux/fsnotify_backend.h | 71 ++++++++++++++++- include/linux/mm.h | 1 + include/uapi/linux/fanotify.h | 18 +++++ mm/filemap.c | 90 ++++++++++++++++++++++ mm/memory.c | 22 ++++++ mm/readahead.c | 13 ++++ security/selinux/hooks.c | 3 +- 21 files changed, 532 insertions(+), 72 deletions(-)