kernel/linux.git/include/uapi/linux/fuse.h, branch v6.6.131

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

fuse: add STATX request

2023-08-16T10:39:38+00:00

Use the same structure as statx. Signed-off-by: Miklos Szeredi

fuse: add a new fuse init flag to relax restrictions in no cache mode

2023-08-16T10:39:16+00:00

FOPEN_DIRECT_IO is usually set by fuse daemon to indicate need of strong coherency, e.g. network filesystems. Thus shared mmap is disabled since it leverages page cache and may write to it, which may cause inconsistence. But FOPEN_DIRECT_IO can be used not for coherency but to reduce memory footprint as well, e.g. reduce guest memory usage with virtiofs. Therefore, add a new fuse init flag FUSE_DIRECT_IO_RELAX to relax restrictions in that mode, currently, it allows shared mmap. One thing to note is to make sure it doesn't break coherency in your use case. Signed-off-by: Hao Xu Signed-off-by: Miklos Szeredi

fuse: add feature flag for expire-only

2023-06-07T14:26:33+00:00

Add an init flag idicating whether the FUSE_EXPIRE_ONLY flag of FUSE_NOTIFY_INVAL_ENTRY is effective. This is needed for backports of this feature, otherwise the server could just check the protocol version. Fixes: 4f8d37020e1f ("fuse: add "expire only" mode to FUSE_NOTIFY_INVAL_ENTRY") Cc: # v6.2 Signed-off-by: Miklos Szeredi

fuse: optional supplementary group in create requests

2023-01-26T16:10:38+00:00

Permission to create an object (create, mkdir, symlink, mknod) needs to take supplementary groups into account. Add a supplementary group request extension. This can contain an arbitrary number of group IDs and can be added to any request. This extension is not added to any request by default. Add FUSE_CREATE_SUPP_GROUP init flag to enable supplementary group info in creation requests. This adds just a single supplementary group that matches the parent group in the case described above. In other cases the extension is not added. Signed-off-by: Miklos Szeredi

fuse: add request extension

2023-01-26T16:10:37+00:00

Will need to add supplementary groups to create messages, so add the general concept of a request extension. A request extension is appended to the end of the main request. It has a header indicating the size and type of the extension. The create security context (fuse_secctx_*) is similar to the generic request extension, so include that as well in a backward compatible manner. Add the total extension length to the request header. The offset of the extension block within the request can be calculated by: inh->len - inh->total_extlen * 8 Signed-off-by: Miklos Szeredi

fuse: allow non-extending parallel direct writes on the same file

2022-11-23T08:10:50+00:00

In general, as of now, in FUSE, direct writes on the same file are serialized over inode lock i.e we hold inode lock for the full duration of the write request. I could not find in fuse code and git history a comment which clearly explains why this exclusive lock is taken for direct writes. Following might be the reasons for acquiring an exclusive lock but not be limited to 1) Our guess is some USER space fuse implementations might be relying on this lock for serialization. 2) The lock protects against file read/write size races. 3) Ruling out any issues arising from partial write failures. This patch relaxes the exclusive lock for direct non-extending writes only. File size extending writes might not need the lock either, but we are not entirely sure if there is a risk to introduce any kind of regression. Furthermore, benchmarking with fio does not show a difference between patch versions that take on file size extension a) an exclusive lock and b) a shared lock. A possible example of an issue with i_size extending writes are write error cases. Some writes might succeed and others might fail for file system internal reasons - for example ENOSPACE. With parallel file size extending writes it _might_ be difficult to revert the action of the failing write, especially to restore the right i_size. With these changes, we allow non-extending parallel direct writes on the same file with the help of a flag called FOPEN_PARALLEL_DIRECT_WRITES. If this flag is set on the file (flag is passed from libfuse to fuse kernel as part of file open/create), we do not take exclusive lock anymore, but instead use a shared lock that allows non-extending writes to run in parallel. FUSE implementations which rely on this inode lock for serialization can continue to do so and serialized direct writes are still the default. Implementations that do not do write serialization need to be updated and need to set the FOPEN_PARALLEL_DIRECT_WRITES flag in their file open/create reply. On patch review there were concerns that network file systems (or vfs multiple mounts of the same file system) might have issues with parallel writes. We believe this is not the case, as this is just a local lock, which network file systems could not rely on anyway. I.e. this lock is just for local consistency. Signed-off-by: Dharmendra Singh Signed-off-by: Bernd Schubert Signed-off-by: Miklos Szeredi

fuse: add "expire only" mode to FUSE_NOTIFY_INVAL_ENTRY

2022-11-23T08:10:49+00:00

Add a flag to entry expiration that lets the filesystem expire a dentry without kicking it out from the cache immediately. This makes a difference for overmounted dentries, where plain invalidation would detach all submounts before dropping the dentry from the cache. If only expiry is set on the dentry, then any overmounts are left alone and until ->d_revalidate() is called. Note: ->d_revalidate() is not called for the case of following a submount, so invalidation will only be triggered for the non-overmounted case. The dentry could also be mounted in a different mount instance, in which case any submounts will still be detached. Suggested-by: Jakob Blomer Signed-off-by: Miklos Szeredi

fuse: implement ->tmpfile()

2022-09-24T05:00:00+00:00

This is basically equivalent to the FUSE_CREATE operation which creates and opens a regular file. Add a new FUSE_TMPFILE operation, otherwise just reuse the protocol and the code for FUSE_CREATE. Acked-by: Christian Brauner (Microsoft) Signed-off-by: Miklos Szeredi

fuse: support per inode DAX in fuse protocol

2021-12-14T10:09:36+00:00

Expand the fuse protocol to support per inode DAX. FUSE_HAS_INODE_DAX flag is added indicating if fuse server/client supporting per inode DAX. It can be conveyed in both FUSE_INIT request and reply. FUSE_ATTR_DAX flag is added indicating if DAX shall be enabled for corresponding file. It is conveyed in FUSE_LOOKUP reply. Signed-off-by: Jeffle Xu Reviewed-by: Vivek Goyal Signed-off-by: Miklos Szeredi