linux-dev/fs/fat, branch master

treewide: use get_random_u32() when possible

2022-10-11T23:42:58Z

The prandom_u32() function has been a deprecated inline wrapper around get_random_u32() for several releases now, and compiles down to the exact same code. Replace the deprecated wrapper with a direct call to the real function. The same also applies to get_random_int(), which is just a wrapper around get_random_u32(). This was done as a basic find and replace. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: Jan Kara # for ext4 Acked-by: Toke Høiland-Jørgensen # for sch_cake Acked-by: Chuck Lever # for nfsd Acked-by: Jakub Kicinski Acked-by: Mika Westerberg # for thunderbolt Acked-by: Darrick J. Wong # for xfs Acked-by: Helge Deller # for parisc Acked-by: Heiko Carstens # for s390 Signed-off-by: Jason A. Donenfeld

Merge tag 'pull-file' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2022-10-07T00:13:18Z

Pull vfs file updates from Al Viro: "struct file-related stuff" * tag 'pull-file' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: dma_buf_getfile(): don't bother with ->f_flags reassignments Change calling conventions for filldir_t locks: fix TOCTOU race when granting write lease

fat: port to vfs{g,u}id_t and associated helpers

2022-09-20T09:09:31Z

A while ago we introduced a dedicated vfs{g,u}id_t type in commit 1e5267cd0895 ("mnt_idmapping: add vfs{g,u}id_t"). We already switched over a good part of the VFS. Ultimately we will remove all legacy idmapped mount helpers that operate only on k{g,u}id_t in favor of the new type safe helpers that operate on vfs{g,u}id_t. Cc: Seth Forshee (Digital Ocean) Cc: Christoph Hellwig Cc: OGAWA Hirofumi Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner (Microsoft) Acked-by: OGAWA Hirofumi

Change calling conventions for filldir_t

2022-08-17T21:25:04Z

filldir_t instances (directory iterators callbacks) used to return 0 for "OK, keep going" or -E... for "stop". Note that it's *NOT* how the error values are reported - the rules for those are callback-dependent and ->iterate{,_shared}() instances only care about zero vs. non-zero (look at emit_dir() and friends). So let's just return bool ("should we keep going?") - it's less confusing that way. The choice between "true means keep going" and "true means stop" is bikesheddable; we have two groups of callbacks - do something for everything in directory, until we run into problem and find an entry in directory and do something to it. The former tended to use 0/-E... conventions - -E on failure. The latter tended to use 0/1, 1 being "stop, we are done". The callers treated anything non-zero as "stop", ignoring which non-zero value did they get. "true means stop" would be more natural for the second group; "true means keep going" - for the first one. I tried both variants and the things like if allocation failed something = -ENOMEM; return true; just looked unnatural and asking for trouble. [folded suggestion from Matthew Wilcox ] Acked-by: Christian Brauner (Microsoft) Signed-off-by: Al Viro

Merge tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-08-07T17:03:24Z

Pull misc updates from Andrew Morton: "Updates to various subsystems which I help look after. lib, ocfs2, fatfs, autofs, squashfs, procfs, etc. A relatively small amount of material this time" * tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits) scripts/gdb: ensure the absolute path is generated on initial source MAINTAINERS: kunit: add David Gow as a maintainer of KUnit mailmap: add linux.dev alias for Brendan Higgins mailmap: update Kirill's email profile: setup_profiling_timer() is moslty not implemented ocfs2: fix a typo in a comment ocfs2: use the bitmap API to simplify code ocfs2: remove some useless functions lib/mpi: fix typo 'the the' in comment proc: add some (hopefully) insightful comments bdi: remove enum wb_congested_state kernel/hung_task: fix address space of proc_dohung_task_timeout_secs lib/lzo/lzo1x_compress.c: replace ternary operator with min() and min_t() squashfs: support reading fragments in readahead call squashfs: implement readahead squashfs: always build "file direct" version of page actor Revert "squashfs: provide backing_dev_info in order to disable read-ahead" fs/ocfs2: Fix spelling typo in comment ia64: old_rr4 added under CONFIG_HUGETLB_PAGE proc: fix test for "vsyscall=xonly" boot option ...

attr: port attribute changes to new types

2022-06-26T16:18:56Z

Now that we introduced new infrastructure to increase the type safety for filesystems supporting idmapped mounts port the first part of the vfs over to them. This ports the attribute changes codepaths to rely on the new better helpers using a dedicated type. Before this change we used to take a shortcut and place the actual values that would be written to inode->i_{g,u}id into struct iattr. This had the advantage that we moved idmappings mostly out of the picture early on but it made reasoning about changes more difficult than it should be. The filesystem was never explicitly told that it dealt with an idmapped mount. The transition to the value that needed to be stored in inode->i_{g,u}id appeared way too early and increased the probability of bugs in various codepaths. We know place the same value in struct iattr no matter if this is an idmapped mount or not. The vfs will only deal with type safe vfs{g,u}id_t. This makes it massively safer to perform permission checks as the type will tell us what checks we need to perform and what helpers we need to use. Fileystems raising FS_ALLOW_IDMAP can't simply write ia_vfs{g,u}id to inode->i_{g,u}id since they are different types. Instead they need to use the dedicated vfs{g,u}id_to_k{g,u}id() helpers that map the vfs{g,u}id into the filesystem. The other nice effect is that filesystems like overlayfs don't need to care about idmappings explicitly anymore and can simply set up struct iattr accordingly directly. Link: https://lore.kernel.org/lkml/CAHk-=win6+ahs1EwLkcq8apqLi_1wXFWbrPf340zYEhObpz4jA@mail.gmail.com [1] Link: https://lore.kernel.org/r/20220621141454.2914719-9-brauner@kernel.org Cc: Seth Forshee Cc: Christoph Hellwig Cc: Aleksa Sarai Cc: Linus Torvalds Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee Signed-off-by: Christian Brauner (Microsoft)

security: pass down mount idmapping to setattr hook

2022-06-26T16:18:56Z

Before this change we used to take a shortcut and place the actual values that would be written to inode->i_{g,u}id into struct iattr. This had the advantage that we moved idmappings mostly out of the picture early on but it made reasoning about changes more difficult than it should be. The filesystem was never explicitly told that it dealt with an idmapped mount. The transition to the value that needed to be stored in inode->i_{g,u}id appeared way too early and increased the probability of bugs in various codepaths. We know place the same value in struct iattr no matter if this is an idmapped mount or not. The vfs will only deal with type safe vfs{g,u}id_t. This makes it massively safer to perform permission checks as the type will tell us what checks we need to perform and what helpers we need to use. Adapt the security_inode_setattr() helper to pass down the mount's idmapping to account for that change. Link: https://lore.kernel.org/r/20220621141454.2914719-8-brauner@kernel.org Cc: Seth Forshee Cc: Christoph Hellwig Cc: Aleksa Sarai Cc: Linus Torvalds Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee Signed-off-by: Christian Brauner (Microsoft)

fat: add renameat2 RENAME_EXCHANGE flag support

2022-06-17T02:58:22Z

The renameat2 RENAME_EXCHANGE flag allows to atomically exchange two paths but is currently not supported by the Linux vfat filesystem driver. Add a vfat_rename_exchange() helper function that implements this support. The super block lock is acquired during the operation to ensure atomicity, and in the error path actions made are reversed also with the mutex held. It makes the operation as transactional as possible, within the limitation impossed by vfat due not having a journal with logs to replay. Link: https://lkml.kernel.org/r/20220610075721.1182745-4-javierm@redhat.com Signed-off-by: Javier Martinez Canillas Acked-by: OGAWA Hirofumi Cc: Alexander Larsson Cc: Christian Kellner Cc: Chung-Chiang Cheng Cc: Colin Walters Cc: Lennart Poettering Cc: Muhammad Usama Anjum Cc: Peter Jones Signed-off-by: Andrew Morton

fat: factor out reusable code in vfat_rename() as helper functions

2022-06-17T02:58:22Z

The vfat_rename() function is quite big and there are code blocks that can be moved into helper functions. This not only simplify the implementation of that function but also allows these helpers to be reused. For example, the helpers can be used by the handler of the RENAME_EXCHANGE flag once this is implemented in a subsequent patch. Link: https://lkml.kernel.org/r/20220610075721.1182745-3-javierm@redhat.com Signed-off-by: OGAWA Hirofumi Signed-off-by: Javier Martinez Canillas Acked-by: OGAWA Hirofumi Cc: Alexander Larsson Cc: Christian Kellner Cc: Chung-Chiang Cheng Cc: Colin Walters Cc: Lennart Poettering Cc: Muhammad Usama Anjum Cc: Peter Jones Signed-off-by: Andrew Morton

fat: add a vfat_rename2() and make existing .rename callback a helper

2022-06-17T02:58:22Z

Patch series "fat: add support for the renameat2 RENAME_EXCHANGE flag", v6. The series adds support for the renameat2 system call RENAME_EXCHANGE flag (which allows to atomically replace two paths) to the vfat filesystem code. There are many use cases for this, but we are particularly interested in making possible for vfat filesystems to be part of OSTree [0] deployments. Currently OSTree relies on symbolic links to make the deployment updates an atomic transactional operation. But RENAME_EXCHANGE could be used [1] to achieve a similar level of robustness when using a vfat filesystem. Patch #1 is just a preparatory patch to introduce the RENAME_EXCHANGE support, patch #2 moves some code blocks in vfat_rename() to a set of helper functions, that can be reused by tvfat_rename_exchange() that's added by patch #3 and finally patch #4 adds some kselftests to test it. This patch (of 4): Currently vfat only supports the RENAME_NOREPLACE flag which is handled by the virtual file system layer but doesn't support the RENAME_EXCHANGE flag. Add a vfat_rename2() function to be used as the .rename callback and move the current vfat_rename() handler to a helper. This is in preparation for implementing the RENAME_NOREPLACE flag using a different helper function. Link: https://lkml.kernel.org/r/20220610075721.1182745-1-javierm@redhat.com Link: https://lkml.kernel.org/r/20220610075721.1182745-2-javierm@redhat.com Signed-off-by: Javier Martinez Canillas Acked-by: OGAWA Hirofumi Cc: Christian Kellner Cc: Peter Jones Cc: Chung-Chiang Cheng Cc: Lennart Poettering Cc: Alexander Larsson Cc: Colin Walters Cc: Muhammad Usama Anjum Signed-off-by: Andrew Morton