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2023-08-10tmpfs,xattr: enable limited user extended attributesHugh Dickins
Enable "user." extended attributes on tmpfs, limiting them by tracking the space they occupy, and deducting that space from the limited ispace (unless tmpfs mounted with nr_inodes=0 to leave that ispace unlimited). tmpfs inodes and simple xattrs are both unswappable, and have to be in lowmem on a 32-bit highmem kernel: so the ispace limit is appropriate for xattrs, without any need for a further mount option. Add simple_xattr_space() to give approximate but deterministic estimate of the space taken up by each xattr: with simple_xattrs_free() outputting the space freed if required (but kernfs and even some tmpfs usages do not require that, so don't waste time on strlen'ing if not needed). Security and trusted xattrs were already supported: for consistency and simplicity, account them from the same pool; though there's a small risk that a tmpfs with enough space before would now be considered too small. When extended attributes are used, "df -i" does show more IUsed and less IFree than can be explained by the inodes: document that (manpage later). xfstests tests/generic which were not run on tmpfs before but now pass: 020 037 062 070 077 097 103 117 337 377 454 486 523 533 611 618 728 with no new failures. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Message-Id: <2e63b26e-df46-5baa-c7d6-f9a8dd3282c5@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: Add default quota limit mount optionsLukas Czerner
Allow system administrator to set default global quota limits at tmpfs mount time. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-7-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-09shmem: quota supportCarlos Maiolino
Now the basic infra-structure is in place, enable quota support for tmpfs. This offers user and group quotas to tmpfs (project quotas will be added later). Also, as other filesystems, the tmpfs quota is not supported within user namespaces yet, so idmapping is not translated. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-6-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-27tmpfs: fix Documentation of noswap and huge mount optionsHugh Dickins
The noswap mount option is surely not one of the three options for sizing: move its description down. The huge= mount option does not accept numeric values: those are just in an internal enum. Delete those numbers, and follow the manpage text more closely (but there's not yet any fadvise() or fcntl() which applies here). /sys/kernel/mm/transparent_hugepage/shmem_enabled is hard to describe, and barely relevant to mounting a tmpfs: just refer to transhuge.rst (while still using the words deny and force, to help as informal reminders). [rdunlap@infradead.org: fixup Docs table for huge mount options] Link: https://lkml.kernel.org/r/20230725052333.26857-1-rdunlap@infradead.org Link: https://lkml.kernel.org/r/986cb0bf-9780-354-9bb-4bf57aadbab@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Fixes: d0f5a85442d1 ("shmem: update documentation") Fixes: 2c6efe9cf2d7 ("shmem: add support to ignore swap") Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: add support to ignore swapLuis Chamberlain
In doing experimentations with shmem having the option to avoid swap becomes a useful mechanism. One of the *raves* about brd over shmem is you can avoid swap, but that's not really a good reason to use brd if we can instead use shmem. Using brd has its own good reasons to exist, but just because "tmpfs" doesn't let you do that is not a great reason to avoid it if we can easily add support for it. I don't add support for reconfiguring incompatible options, but if we really wanted to we can add support for that. To avoid swap we use mapping_set_unevictable() upon inode creation, and put a WARN_ON_ONCE() stop-gap on writepages() for reclaim. Link: https://lkml.kernel.org/r/20230309230545.2930737-7-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Christian Brauner <brauner@kernel.org> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28shmem: update documentationLuis Chamberlain
Update the docs to reflect a bit better why some folks prefer tmpfs over ramfs and clarify a bit more about the difference between brd ramdisks. While at it, add THP docs for tmpfs, both the mount options and the sysfs file. Link: https://lkml.kernel.org/r/20230309230545.2930737-6-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: David Hildenbrand <david@redhat.com> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2020-12-15tmpfs: fix Documentation nitsRandy Dunlap
Fix a typo, punctuation, use uppercase for CPUs, and limit tmpfs to keeping only its files in virtual memory (phrasing). Link: https://lkml.kernel.org/r/20201202010934.18566-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Hugh Dickins <hughd@google.com> Cc: Chris Down <chris@chrisdown.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07tmpfs: support 64-bit inums per-sbChris Down
The default is still set to inode32 for backwards compatibility, but system administrators can opt in to the new 64-bit inode numbers by either: 1. Passing inode64 on the command line when mounting, or 2. Configuring the kernel with CONFIG_TMPFS_INODE64=y The inode64 and inode32 names are used based on existing precedent from XFS. [hughd@google.com: Kconfig fixes] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008011928010.13320@eggly.anvils Signed-off-by: Chris Down <chris@chrisdown.name> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/8b23758d0c66b5e2263e08baf9c4b6a7565cbd8f.1594661218.git.chris@chrisdown.name Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-02docs: filesystems: convert tmpfs.txt to ReSTMauro Carvalho Chehab
- Add a SPDX header; - Add a document title; - Some whitespace fixes and new line breaks; - Mark literal blocks as such; - Add table markups; - Use :field: markup; - Add it to filesystems/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/30397a47a78ca59760fbc0fc5f50c5f1002d487a.1581955849.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>