kernel/linux.git/fs/fuse/inode.c, branch v6.6.131

fuse: zero initialize inode private data

2025-11-24T09:29:30+00:00

[ Upstream commit 3ca1b311181072415b6432a169de765ac2034e5a ] This is slightly tricky, since the VFS uses non-zeroing allocation to preserve some fields that are left in a consistent state. Reported-by: Chunsheng Luo Closes: https://lore.kernel.org/all/20250818083224.229-1-luochunsheng@ustc.edu/ Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: fix UAF in rcu pathwalks

2024-08-29T15:33:33+00:00

[ Upstream commit 053fc4f755ad43cf35210677bcba798ccdc48d0c ] ->permission(), ->get_link() and ->inode_get_acl() might dereference ->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns as well) when called from rcu pathwalk. Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info and dropping ->user_ns rcu-delayed too. Signed-off-by: Al Viro Signed-off-by: Sasha Levin

fuse: verify {g,u}id mount options correctly

2024-08-03T06:54:14+00:00

commit 525bd65aa759ec320af1dc06e114ed69733e9e23 upstream. As was done in 0200679fc795 ("tmpfs: verify {g,u}id mount options correctly") we need to validate that the requested uid and/or gid is representable in the filesystem's idmapping. Cribbing from the above commit log, The contract for {g,u}id mount options and {g,u}id values in general set from userspace has always been that they are translated according to the caller's idmapping. In so far, fuse has been doing the correct thing. But since fuse is mountable in unprivileged contexts it is also necessary to verify that the resulting {k,g}uid is representable in the namespace of the superblock. Fixes: c30da2e981a7 ("fuse: convert to use the new mount API") Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Eric Sandeen Link: https://lore.kernel.org/r/8f07d45d-c806-484d-a2e3-7a2199df1cd2@redhat.com Reviewed-by: Christian Brauner Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman

fuse: don't unhash root

2024-04-03T13:28:25+00:00

[ Upstream commit b1fe686a765e6c0d71811d825b5a1585a202b777 ] The root inode is assumed to be always hashed. Do not unhash the root inode even if it is marked BAD. Fixes: 5d069dbe8aaf ("fuse: fix bad inode") Cc: # v5.11 Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: share lookup state between submount and its parent

2023-12-20T16:01:51+00:00

commit c4d361f66ac91db8fc65061a9671682f61f4ca9d upstream. Fuse submounts do not perform a lookup for the nodeid that they inherit from their parent. Instead, the code decrements the nlookup on the submount's fuse_inode when it is instantiated, and no forget is performed when a submount root is evicted. Trouble arises when the submount's parent is evicted despite the submount itself being in use. In this author's case, the submount was in a container and deatched from the initial mount namespace via a MNT_DEATCH operation. When memory pressure triggered the shrinker, the inode from the parent was evicted, which triggered enough forgets to render the submount's nodeid invalid. Since submounts should still function, even if their parent goes away, solve this problem by sharing refcounted state between the parent and its submount. When all of the references on this shared state reach zero, it's safe to forget the final lookup of the fuse nodeid. Signed-off-by: Krister Johansen Cc: stable@vger.kernel.org Fixes: 1866d779d5d2 ("fuse: Allow fuse_fill_super_common() for submounts") Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: Rename DIRECT_IO_RELAX to DIRECT_IO_ALLOW_MMAP

2023-12-20T16:01:51+00:00

commit c55e0a55b165202f18cbc4a20650d2e1becd5507 upstream. Although DIRECT_IO_RELAX's initial usage is to allow shared mmap, its description indicates a purpose of reducing memory footprint. This may imply that it could be further used to relax other DIRECT_IO operations in the future. Replace it with a flag DIRECT_IO_ALLOW_MMAP which does only one thing, allow shared mmap of DIRECT_IO files while still bypassing the cache on regular reads and writes. [Miklos] Also Keep DIRECT_IO_RELAX definition for backward compatibility. Signed-off-by: Tyler Fanelli Fixes: e78662e818f9 ("fuse: add a new fuse init flag to relax restrictions in no cache mode") Cc: # v6.6 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

Merge tag 'fuse-update-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2023-09-05T19:45:55+00:00

Pull fuse updates from Miklos Szeredi: - Revert non-waiting FLUSH due to a regression - Fix a lookup counter leak in readdirplus - Add an option to allow shared mmaps in no-cache mode - Add btime support and statx intrastructure to the protocol - Invalidate positive/negative dentry on failed create/delete * tag 'fuse-update-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: fuse: conditionally fill kstat in fuse_do_statx() fuse: invalidate dentry on EEXIST creates or ENOENT deletes fuse: cache btime fuse: implement statx fuse: add ATTR_TIMEOUT macro fuse: add STATX request fuse: handle empty request_mask in statx fuse: write back dirty pages before direct write in direct_io_relax mode fuse: add a new fuse init flag to relax restrictions in no cache mode fuse: invalidate page cache pages before direct write fuse: nlookup missing decrement in fuse_direntplus_link Revert "fuse: in fuse_flush only wait if someone wants the return code"

Merge tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2023-08-28T16:31:32+00:00

Pull vfs timestamp updates from Christian Brauner: "This adds VFS support for multi-grain timestamps and converts tmpfs, xfs, ext4, and btrfs to use them. This carries acks from all relevant filesystems. The VFS always uses coarse-grained timestamps when updating the ctime and mtime after a change. This has the benefit of allowing filesystems to optimize away a lot of metadata updates, down to around 1 per jiffy, even when a file is under heavy writes. Unfortunately, this has always been an issue when we're exporting via NFSv3, which relies on timestamps to validate caches. A lot of changes can happen in a jiffy, so timestamps aren't sufficient to help the client decide to invalidate the cache. Even with NFSv4, a lot of exported filesystems don't properly support a change attribute and are subject to the same problems with timestamp granularity. Other applications have similar issues with timestamps (e.g., backup applications). If we were to always use fine-grained timestamps, that would improve the situation, but that becomes rather expensive, as the underlying filesystem would have to log a lot more metadata updates. This introduces fine-grained timestamps that are used when they are actively queried. This uses the 31st bit of the ctime tv_nsec field to indicate that something has queried the inode for the mtime or ctime. When this flag is set, on the next mtime or ctime update, the kernel will fetch a fine-grained timestamp instead of the usual coarse-grained one. As POSIX generally mandates that when the mtime changes, the ctime must also change the kernel always stores normalized ctime values, so only the first 30 bits of the tv_nsec field are ever used. Filesytems can opt into this behavior by setting the FS_MGTIME flag in the fstype. Filesystems that don't set this flag will continue to use coarse-grained timestamps. Various preparatory changes, fixes and cleanups are included: - Fixup all relevant places where POSIX requires updating ctime together with mtime. This is a wide-range of places and all maintainers provided necessary Acks. - Add new accessors for inode->i_ctime directly and change all callers to rely on them. Plain accesses to inode->i_ctime are now gone and it is accordingly rename to inode->__i_ctime and commented as requiring accessors. - Extend generic_fillattr() to pass in a request mask mirroring in a sense the statx() uapi. This allows callers to pass in a request mask to only get a subset of attributes filled in. - Rework timestamp updates so it's possible to drop the @now parameter the update_time() inode operation and associated helpers. - Add inode_update_timestamps() and convert all filesystems to it removing a bunch of open-coding" * tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (107 commits) btrfs: convert to multigrain timestamps ext4: switch to multigrain timestamps xfs: switch to multigrain timestamps tmpfs: add support for multigrain timestamps fs: add infrastructure for multigrain timestamps fs: drop the timespec64 argument from update_time xfs: have xfs_vn_update_time gets its own timestamp fat: make fat_update_time get its own timestamp fat: remove i_version handling from fat_update_time ubifs: have ubifs_update_time use inode_update_timestamps btrfs: have it use inode_update_timestamps fs: drop the timespec64 arg from generic_update_time fs: pass the request_mask to generic_fillattr fs: remove silly warning from current_time gfs2: fix timestamp handling on quota inodes fs: rename i_ctime field to __i_ctime selinux: convert to ctime accessor functions security: convert to ctime accessor functions apparmor: convert to ctime accessor functions sunrpc: convert to ctime accessor functions ...

fuse: cache btime

2023-08-21T10:14:59+00:00

Not all inode attributes are supported by all filesystems, but for the basic stats (which are returned by stat(2) and friends) all of them will have some value, even if that doesn't reflect a real attribute of the file. Btime is different, in that filesystems are free to report or not report a value in statx. If the value is available, then STATX_BTIME bit is set in stx_mask. When caching the value of btime, remember the availability of the attribute as well as the value (if available). This is done by using the FUSE_I_BTIME bit in fuse_inode->state to indicate availability, while using fuse_inode->inval_mask & STATX_BTIME to indicate the state of the cache itself (i.e. set if cache is invalid, and cleared if cache is valid). Signed-off-by: Miklos Szeredi

fuse: implement statx

2023-08-21T10:14:49+00:00

Allow querying btime. When btime is requested in mask, then FUSE_STATX request is sent. Otherwise keep using FUSE_GETATTR. The userspace interface for statx matches that of the statx(2) API. However there are limitations on how this interface is used: - returned basic stats and btime are used, stx_attributes, etc. are ignored - always query basic stats and btime, regardless of what was requested - requested sync type is ignored, the default is passed to the server - if server returns with some attributes missing from the result_mask, then no attributes will be cached - btime is not cached yet (next patch will fix that) For new inodes initialize fi->inval_mask to "all invalid", instead of "all valid" as previously. Also only clear basic stats from inval_mask when caching attributes. This will result in the caching logic not thinking that btime is cached. Signed-off-by: Miklos Szeredi