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| author | Hao Xu <howeyxu@tencent.com> | 2023-08-01 16:06:46 +0800 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2023-08-16 12:39:16 +0200 |
| commit | e78662e818f9478e70912cc2970ca632ec9f3635 (patch) | |
| tree | 314381c812fb07d72c61135a69fe27caf50a191e /include/uapi | |
| parent | 80e4f25262f9f1a5f08154fafaa6ac4371043d35 (diff) | |
| download | linux-stable-e78662e818f9478e70912cc2970ca632ec9f3635.tar.gz linux-stable-e78662e818f9478e70912cc2970ca632ec9f3635.tar.bz2 linux-stable-e78662e818f9478e70912cc2970ca632ec9f3635.zip | |
fuse: add a new fuse init flag to relax restrictions in no cache mode
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 <howeyxu@tencent.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/fuse.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index b3fcab13fcd3..c2da9503b04e 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -207,6 +207,9 @@ * - add FUSE_EXT_GROUPS * - add FUSE_CREATE_SUPP_GROUP * - add FUSE_HAS_EXPIRE_ONLY + * + * 7.39 + * - add FUSE_DIRECT_IO_RELAX */ #ifndef _LINUX_FUSE_H @@ -242,7 +245,7 @@ #define FUSE_KERNEL_VERSION 7 /** Minor version number of this interface */ -#define FUSE_KERNEL_MINOR_VERSION 38 +#define FUSE_KERNEL_MINOR_VERSION 39 /** The node ID of the root inode */ #define FUSE_ROOT_ID 1 @@ -371,6 +374,8 @@ struct fuse_file_lock { * FUSE_CREATE_SUPP_GROUP: add supplementary group info to create, mkdir, * symlink and mknod (single group that matches parent) * FUSE_HAS_EXPIRE_ONLY: kernel supports expiry-only entry invalidation + * FUSE_DIRECT_IO_RELAX: relax restrictions in FOPEN_DIRECT_IO mode, for now + * allow shared mmap */ #define FUSE_ASYNC_READ (1 << 0) #define FUSE_POSIX_LOCKS (1 << 1) @@ -409,6 +414,7 @@ struct fuse_file_lock { #define FUSE_HAS_INODE_DAX (1ULL << 33) #define FUSE_CREATE_SUPP_GROUP (1ULL << 34) #define FUSE_HAS_EXPIRE_ONLY (1ULL << 35) +#define FUSE_DIRECT_IO_RELAX (1ULL << 36) /** * CUSE INIT request/reply flags |