[RFC,18/24] erofs: introduce iget alternative to C

Message ID	20240916135634.98554-19-toolmanp@tlmp.cc (mailing list archive)
State	New
Headers	show Received: from mail.tlmp.cc (unknown [148.135.17.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27528188017; Mon, 16 Sep 2024 13:57:14 +0000 (UTC) From: Yiyang Wu <toolmanp@tlmp.cc> To: linux-erofs@lists.ozlabs.org Cc: rust-for-linux@vger.kernel.org, linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org> Subject: [RFC PATCH 18/24] erofs: introduce iget alternative to C Date: Mon, 16 Sep 2024 21:56:28 +0800 Message-ID: <20240916135634.98554-19-toolmanp@tlmp.cc> In-Reply-To: <20240916135634.98554-1-toolmanp@tlmp.cc> References: <20240916135634.98554-1-toolmanp@tlmp.cc> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	erofs: introduce Rust implementation \| expand [RFC,00/24] erofs: introduce Rust implementation [RFC,01/24] erofs: lift up erofs_fill_inode to global [RFC,02/24] erofs: add superblock data structure in Rust [RFC,03/24] erofs: add Errno in Rust [RFC,04/24] erofs: add xattrs data structure in Rust [RFC,05/24] erofs: add inode data structure in Rust [RFC,06/24] erofs: add alloc_helper in Rust [RFC,07/24] erofs: add data abstraction in Rust [RFC,08/24] erofs: add device data structure in Rust [RFC,09/24] erofs: add continuous iterators in Rust [RFC,10/24] erofs: add device_infos implementation in Rust [RFC,11/24] erofs: add map data structure in Rust [RFC,12/24] erofs: add directory entry data structure in Rust [RFC,13/24] erofs: add runtime filesystem and inode in Rust [RFC,14/24] erofs: add block mapping capability in Rust [RFC,15/24] erofs: add iter methods in filesystem in Rust [RFC,16/24] erofs: implement dir and inode operations in Rust [RFC,17/24] erofs: introduce Rust SBI to C [RFC,18/24] erofs: introduce iget alternative to C [RFC,19/24] erofs: introduce namei alternative to C [RFC,20/24] erofs: introduce readdir alternative to C [RFC,21/24] erofs: introduce erofs_map_blocks alternative to C [RFC,22/24] erofs: add skippable iters in Rust [RFC,23/24] erofs: implement xattrs operations in Rust [RFC,24/24] erofs: introduce xattrs replacement to C

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile index dfa03edbe29a..46de6f490ca2 100644 --- a/fs/erofs/Makefile +++ b/fs/erofs/Makefile @@ -9,4 +9,4 @@ erofs-$(CONFIG_EROFS_FS_ZIP_DEFLATE) += decompressor_deflate.o erofs-$(CONFIG_EROFS_FS_ZIP_ZSTD) += decompressor_zstd.o erofs-$(CONFIG_EROFS_FS_BACKED_BY_FILE) += fileio.o erofs-$(CONFIG_EROFS_FS_ONDEMAND) += fscache.o -erofs-$(CONFIG_EROFS_FS_RUST) += super_rs.o rust_helpers.o +erofs-$(CONFIG_EROFS_FS_RUST) += super_rs.o inode_rs.o rust_helpers.o diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c index d2fd51fcebd2..b8467272a670 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -269,7 +269,7 @@ int erofs_fill_inode(struct inode *inode) * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down * so that it will fit. */ -static ino_t erofs_squash_ino(erofs_nid_t nid) +ino_t erofs_squash_ino(erofs_nid_t nid) { ino_t ino = (ino_t)nid; @@ -278,12 +278,12 @@ static ino_t erofs_squash_ino(erofs_nid_t nid) return ino; } -static int erofs_iget5_eq(struct inode *inode, void *opaque) +int erofs_iget5_eq(struct inode *inode, void *opaque) { return EROFS_I(inode)->nid == *(erofs_nid_t *)opaque; } -static int erofs_iget5_set(struct inode *inode, void *opaque) +int erofs_iget5_set(struct inode *inode, void *opaque) { const erofs_nid_t nid = *(erofs_nid_t *)opaque; @@ -292,6 +292,7 @@ static int erofs_iget5_set(struct inode *inode, void *opaque) return 0; } +#ifndef CONFIG_EROFS_FS_RUST struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid) { struct inode *inode; @@ -312,6 +313,7 @@ struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid) } return inode; } +#endif int erofs_getattr(struct mnt_idmap *idmap, const struct path *path, struct kstat *stat, u32 request_mask, diff --git a/fs/erofs/inode_rs.rs b/fs/erofs/inode_rs.rs new file mode 100644 index 000000000000..5cca2ae581ac --- /dev/null +++ b/fs/erofs/inode_rs.rs @@ -0,0 +1,59 @@ +// Copyright 2024 Yiyang Wu +// SPDX-License-Identifier: MIT or GPL-2.0-or-later + +//! EROFS Rust Kernel Module Helpers Implementation +//! This is only for experimental purpose. Feedback is always welcome. + +#[allow(dead_code)] +#[allow(missing_docs)] +pub(crate) mod rust; + +use core::ffi::*; +use core::mem::{offset_of, size_of}; +use core::ptr::NonNull; +use kernel::bindings::{inode, super_block}; +use kernel::container_of; +use rust::{ + erofs_sys::{operations::*, *}, + kinode::*, + ksuperblock::erofs_sbi, +}; + +/// Used as a size hint to be exported to kmem_caceh_create +#[no_mangle] +pub static EROFS_INODE_SIZE_RUST: c_uint = size_of::<KernelInode>() as c_uint; + +/// Used as a hint offset to be exported so EROFS_VFS_I to find the embedded the vfs inode. +#[no_mangle] +pub static EROFS_VFS_INODE_OFFSET_RUST: c_ulong = offset_of!(KernelInode, k_inode) as c_ulong; + +/// Used as a hint offset to be exported to EROFS_I to find the embedded c side erofs_inode. +#[no_mangle] +pub static EROFS_I_OFFSET_RUST: c_long = + offset_of!(KernelInode, k_opaque) as c_long - offset_of!(KernelInode, k_inode) as c_long; + +/// Exported as iget replacement +#[no_mangle] +pub unsafe extern "C" fn erofs_iget_rust(sb: NonNull<super_block>, nid: Nid) -> *mut c_void { + // SAFETY: The super_block is initialized when the erofs_alloc_sbi_rust is called. + let sbi = erofs_sbi(sb); + read_inode(sbi.filesystem.as_ref(), &mut sbi.inodes, nid) + .map_or_else(|e| e.into(), |inode| inode.k_inode.as_mut_ptr().cast()) +} + +fn try_fill_inode(k_inode: NonNull<inode>, nid: Nid) -> PosixResult<()> { + // SAFETY: The super_block is initialized when the erofs_fill_inode_rust is called. + let sbi = erofs_sbi(unsafe { NonNull::new(k_inode.as_ref().i_sb).unwrap() }); + // SAFETY: k_inode is a part of KernelInode. + let erofs_inode: &mut KernelInode = unsafe { + &mut *(container_of!(k_inode.as_ptr(), KernelInode, k_inode) as *mut KernelInode) + }; + erofs_inode.info.write(sbi.filesystem.read_inode_info(nid)?); + erofs_inode.nid.write(nid); + Ok(()) +} +/// Exported as fill_inode additional fill inode +#[no_mangle] +pub unsafe extern "C" fn erofs_fill_inode_rust(k_inode: NonNull<inode>, nid: Nid) -> c_int { + try_fill_inode(k_inode, nid).map_or_else(|e| i32::from(e) as c_int, |_| 0) +} diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 18e67219fbc8..42ce84783be7 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -306,10 +306,20 @@ struct erofs_inode { #endif /* CONFIG_EROFS_FS_ZIP */ }; /* the corresponding vfs inode */ +#ifndef CONFIG_EROFS_FS_RUST struct inode vfs_inode; +#endif }; +#ifdef CONFIG_EROFS_FS_RUST +#define EROFS_I(ptr) (*(struct erofs_inode **)(((void *)(ptr)) + \ + EROFS_I_OFFSET_RUST)) +#define EROFS_I_VFS(ptr) ((struct inode *)(((void *)(ptr)) + EROFS_VFS_INODE_OFFSET_RUST)) +#define EROFS_I_RUST(ptr) ((void *)(ptr) - EROFS_VFS_INODE_OFFSET_RUST) +#else #define EROFS_I(ptr) container_of(ptr, struct erofs_inode, vfs_inode) +#define EROFS_I_VFS(ptr) (&((struct erofs_inode *)(ptr))->vfs_inode) +#endif static inline erofs_off_t erofs_iloc(struct inode *inode) { @@ -427,10 +437,18 @@ void erofs_onlinefolio_init(struct folio *folio); void erofs_onlinefolio_split(struct folio *folio); void erofs_onlinefolio_end(struct folio *folio, int err); int erofs_fill_inode(struct inode *inode); +ino_t erofs_squash_ino(erofs_nid_t nid); +int erofs_iget5_eq(struct inode *inode, void *opaque); +int erofs_iget5_set(struct inode *inode, void *opaque); +#ifdef CONFIG_EROFS_FS_RUST +#define erofs_iget erofs_iget_rust +#else struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid); +#endif int erofs_getattr(struct mnt_idmap *idmap, const struct path *path, struct kstat *stat, u32 request_mask, unsigned int query_flags); + int erofs_namei(struct inode *dir, const struct qstr *name, erofs_nid_t *nid, unsigned int *d_type); @@ -538,6 +556,21 @@ static inline struct bio *erofs_fscache_bio_alloc(struct erofs_map_dev *mdev) { static inline void erofs_fscache_submit_bio(struct bio *bio) {} #endif +#ifdef CONFIG_EROFS_FS_RUST +extern int erofs_init_rust(void); +extern void erofs_destroy_rust(void); +extern void erofs_init_inode_rust(struct inode *inode); +extern void erofs_free_inode_rust(struct inode *inode); +#else +static inline int erofs_init_rust(void) +{ + return 0; +} +static inline void erofs_destroy_rust(void) {} +static inline void erofs_init_inode_rust(struct inode *inode) {} +static inline void erofs_free_inode_rust(struct inode *inode) {} +#endif + #define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */ #endif /* __EROFS_INTERNAL_H */ diff --git a/fs/erofs/rust/kinode.rs b/fs/erofs/rust/kinode.rs index df6de40d0594..fac72bd8b6b3 100644 --- a/fs/erofs/rust/kinode.rs +++ b/fs/erofs/rust/kinode.rs @@ -1,16 +1,23 @@ // Copyright 2024 Yiyang Wu // SPDX-License-Identifier: MIT or GPL-2.0-or-later -use core::ffi::c_void; +use core::ffi::*; use core::mem::MaybeUninit; use core::ptr::NonNull; use kernel::bindings::{inode, super_block}; +use kernel::container_of; +use super::erofs_sys::errnos::*; use super::erofs_sys::inode::*; use super::erofs_sys::superblock::*; use super::erofs_sys::*; +extern "C" { + #[link_name = "erofs_iget_locked_rust_helper"] + fn iget_locked(sb: NonNull<c_void>, nid: Nid) -> *mut c_void; +} + #[repr(C)] pub(crate) struct KernelInode { pub(crate) info: MaybeUninit<InodeInfo>, @@ -21,7 +28,12 @@ pub(crate) struct KernelInode { impl Inode for KernelInode { fn new(_sb: &SuperBlock, _info: InodeInfo, _nid: Nid) -> Self { - unimplemented!(); + Self { + info: MaybeUninit::uninit(), + nid: MaybeUninit::uninit(), + k_inode: MaybeUninit::uninit(), + k_opaque: MaybeUninit::uninit(), + } } fn nid(&self) -> Nid { unsafe { self.nid.assume_init() } @@ -37,8 +49,17 @@ pub(crate) struct KernelInodeCollection { impl InodeCollection for KernelInodeCollection { type I = KernelInode; - fn iget(&mut self, _nid: Nid, _f: &dyn FileSystem<Self::I>) -> PosixResult<&mut Self::I> { - unimplemented!(); + fn iget(&mut self, nid: Nid, _f: &dyn FileSystem<Self::I>) -> PosixResult<&mut Self::I> { + // SAFETY: iget_locked is safe to call here. + let k_inode = unsafe { iget_locked(self.sb.cast(), nid) }; + if is_value_err(k_inode.cast()) { + return Err(Errno::from(k_inode as i32)); + } else { + let erofs_inode: &mut KernelInode = + // SAFETY: iget_locked returns a valid pointer to a vfs inode and it's embedded in a KernelInode. + unsafe { &mut *(container_of!(k_inode, KernelInode, k_inode) as *mut KernelInode) }; + return Ok(erofs_inode); + } } } diff --git a/fs/erofs/rust_bindings.h b/fs/erofs/rust_bindings.h index 9695c5ed5a7c..657f109dd6e7 100644 --- a/fs/erofs/rust_bindings.h +++ b/fs/erofs/rust_bindings.h @@ -6,7 +6,19 @@ #include <linux/fs.h> + +typedef u64 erofs_nid_t; +typedef u64 erofs_off_t; +/* data type for filesystem-wide blocks number */ +typedef u32 erofs_blk_t; + extern const unsigned long EROFS_SB_INFO_OFFSET_RUST; +extern const unsigned int EROFS_INODE_SIZE_RUST; +extern const unsigned long EROFS_VFS_INODE_OFFSET_RUST; +extern const long EROFS_I_OFFSET_RUST; + extern void *erofs_alloc_sbi_rust(struct super_block *sb); extern void *erofs_free_sbi_rust(struct super_block *sb); +extern int erofs_iget5_eq_rust(struct inode *inode, void *opaque); +extern struct inode *erofs_iget_rust(struct super_block *sb, erofs_nid_t nid); #endif diff --git a/fs/erofs/rust_helpers.c b/fs/erofs/rust_helpers.c index 5fdc158ed9ef..94e9153fc3ff 100644 --- a/fs/erofs/rust_helpers.c +++ b/fs/erofs/rust_helpers.c @@ -1,5 +1,7 @@ #include "rust_helpers.h" +static struct kmem_cache *erofs_inode_cachep __read_mostly; + static void erofs_init_metabuf_rust_helper(struct erofs_buf *buf, struct super_block *sb, struct erofs_sb_info *sbi) @@ -29,3 +31,56 @@ void erofs_put_metabuf_rust_helper(void *addr) .kmap_type = EROFS_KMAP, }); } + +int erofs_init_rust(void) +{ + erofs_inode_cachep = kmem_cache_create("erofs_inode", + sizeof(struct erofs_inode), 0, + SLAB_RECLAIM_ACCOUNT, NULL); + if (!erofs_inode_cachep) + return -ENOMEM; + return 0; +} + +void erofs_destroy_rust(void) +{ + if (erofs_inode_cachep) + kmem_cache_destroy(erofs_inode_cachep); +} + +void erofs_init_inode_rust(struct inode *inode) +{ + EROFS_I(inode) = kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL); +} + +void erofs_free_inode_rust(struct inode *inode) +{ + struct erofs_inode *vi = EROFS_I(inode); + if (vi) + kmem_cache_free(erofs_inode_cachep, vi); +} + +struct inode *erofs_iget_locked_rust_helper(struct super_block *sb, erofs_nid_t nid) +{ + struct inode *inode; + int err; + + inode = iget5_locked(sb, erofs_squash_ino(nid), erofs_iget5_eq, + erofs_iget5_set, &nid); + if (!inode) + return ERR_PTR(-ENOMEM); + + err = erofs_fill_inode(inode); + if(err) + goto err_out; + + err = erofs_fill_inode_rust(inode, nid); + if(err) + goto err_out; + + return inode; +err_out: + if (err) + iget_failed(inode); + return ERR_PTR(err); +} diff --git a/fs/erofs/rust_helpers.h b/fs/erofs/rust_helpers.h index 158b21438314..5bcd452f6d82 100644 --- a/fs/erofs/rust_helpers.h +++ b/fs/erofs/rust_helpers.h @@ -17,5 +17,7 @@ void *erofs_read_metabuf_rust_helper(struct super_block *sb, struct erofs_sb_info *sbi, erofs_off_t offset); void erofs_put_metabuf_rust_helper(void *addr); - +extern int erofs_fill_inode_rust(struct inode *inode, erofs_nid_t nid); +struct inode *erofs_iget_locked_rust_helper(struct super_block *sb, + erofs_nid_t nid); #endif diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 61f138a7d8e2..659502bdf5fe 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -81,22 +81,23 @@ static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata) static void erofs_inode_init_once(void *ptr) { - struct erofs_inode *vi = ptr; - - inode_init_once(&vi->vfs_inode); + inode_init_once(EROFS_I_VFS(ptr)); + erofs_init_inode_rust(EROFS_I_VFS(ptr)); } static struct inode *erofs_alloc_inode(struct super_block *sb) { - struct erofs_inode *vi = + void *ptr = alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL); - if (!vi) + if (!ptr) return NULL; +#ifndef CONFIG_EROFS_FS_RUST /* zero out everything except vfs_inode */ - memset(vi, 0, offsetof(struct erofs_inode, vfs_inode)); - return &vi->vfs_inode; + memset(ptr, 0, offsetof(struct erofs_inode, vfs_inode)); +#endif + return EROFS_I_VFS(ptr); } static void erofs_free_inode(struct inode *inode) @@ -106,7 +107,12 @@ static void erofs_free_inode(struct inode *inode) if (inode->i_op == &erofs_fast_symlink_iops) kfree(inode->i_link); kfree(vi->xattr_shared_xattrs); + erofs_free_inode_rust(inode); +#ifdef CONFIG_EROFS_FS_RUST + kmem_cache_free(erofs_inode_cachep, EROFS_I_RUST(inode)); +#else kmem_cache_free(erofs_inode_cachep, vi); +#endif } /* read variable-sized metadata, offset will be aligned by 4-byte */ @@ -871,13 +877,25 @@ static int __init erofs_module_init(void) erofs_check_ondisk_layout_definitions(); +#ifndef CONFIG_EROFS_FS_RUST erofs_inode_cachep = kmem_cache_create("erofs_inode", sizeof(struct erofs_inode), 0, SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT, erofs_inode_init_once); +#else + erofs_inode_cachep = kmem_cache_create("erofs_inode_rust", + EROFS_INODE_SIZE_RUST, 0, + SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT, + erofs_inode_init_once); +#endif + if (!erofs_inode_cachep) return -ENOMEM; + err = erofs_init_rust(); + if(err) + goto rust_err; + err = erofs_init_shrinker(); if (err) goto shrinker_err; @@ -904,6 +922,8 @@ static int __init erofs_module_init(void) erofs_exit_shrinker(); shrinker_err: kmem_cache_destroy(erofs_inode_cachep); +rust_err: + erofs_destroy_rust(); return err; }

[RFC,18/24] erofs: introduce iget alternative to C

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