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Mon, 21 Nov 2022 18:16:25 -0800 (PST) Date: Mon, 21 Nov 2022 18:15:29 -0800 In-Reply-To: <20221122021536.1629178-1-drosen@google.com> Mime-Version: 1.0 References: <20221122021536.1629178-1-drosen@google.com> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog Message-ID: <20221122021536.1629178-15-drosen@google.com> Subject: [RFC PATCH v2 14/21] fuse-bpf: support FUSE_READDIR From: Daniel Rosenberg To: Miklos Szeredi Cc: Amir Goldstein , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, kernel-team@android.com, Daniel Rosenberg , Paul Lawrence Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org Signed-off-by: Daniel Rosenberg Signed-off-by: Paul Lawrence --- fs/fuse/backing.c | 185 ++++++++++++++++++++++++++++++++++++++ fs/fuse/fuse_i.h | 6 ++ fs/fuse/readdir.c | 5 ++ include/uapi/linux/fuse.h | 6 ++ 4 files changed, 202 insertions(+) diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c index 425815d7f5dc..a15b5c107cfe 100644 --- a/fs/fuse/backing.c +++ b/fs/fuse/backing.c @@ -1597,6 +1597,191 @@ int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *entry) dir, entry); } +struct fuse_read_io { + struct fuse_read_in fri; + struct fuse_read_out fro; +}; + +static int fuse_readdir_initialize_in(struct fuse_args *fa, struct fuse_read_io *frio, + struct file *file, struct dir_context *ctx, + bool *force_again, bool *allow_force, bool is_continued) +{ + struct fuse_file *ff = file->private_data; + + *fa = (struct fuse_args) { + .nodeid = ff->nodeid, + .opcode = FUSE_READDIR, + .in_numargs = 1, + .in_args[0] = (struct fuse_in_arg) { + .size = sizeof(frio->fri), + .value = &frio->fri, + }, + }; + + frio->fri = (struct fuse_read_in) { + .fh = ff->fh, + .offset = ctx->pos, + .size = PAGE_SIZE, + }; + + *force_again = false; + *allow_force = true; + return 0; +} + +static int fuse_readdir_initialize_out(struct fuse_args *fa, struct fuse_read_io *frio, + struct file *file, struct dir_context *ctx, + bool *force_again, bool *allow_force, bool is_continued) +{ + u8 *page = (u8 *)__get_free_page(GFP_KERNEL); + + if (!page) + return -ENOMEM; + + fa->out_argvar = true; + fa->out_numargs = 2; + fa->out_args[0] = (struct fuse_arg) { + .size = sizeof(frio->fro), + .value = &frio->fro, + }; + fa->out_args[1] = (struct fuse_arg) { + .size = PAGE_SIZE, + .value = page, + }; + frio->fro = (struct fuse_read_out) { + .again = 0, + .offset = 0, + }; + + return 0; +} + +struct extfuse_ctx { + struct dir_context ctx; + u8 *addr; + size_t offset; +}; + +static bool filldir(struct dir_context *ctx, const char *name, int namelen, + loff_t offset, u64 ino, unsigned int d_type) +{ + struct extfuse_ctx *ec = container_of(ctx, struct extfuse_ctx, ctx); + struct fuse_dirent *fd = (struct fuse_dirent *)(ec->addr + ec->offset); + + if (ec->offset + sizeof(struct fuse_dirent) + namelen > PAGE_SIZE) + return false; + + *fd = (struct fuse_dirent) { + .ino = ino, + .off = offset, + .namelen = namelen, + .type = d_type, + }; + + memcpy(fd->name, name, namelen); + ec->offset += FUSE_DIRENT_SIZE(fd); + + return true; +} + +static int parse_dirfile(char *buf, size_t nbytes, struct dir_context *ctx) +{ + while (nbytes >= FUSE_NAME_OFFSET) { + struct fuse_dirent *dirent = (struct fuse_dirent *) buf; + size_t reclen = FUSE_DIRENT_SIZE(dirent); + + if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) + return -EIO; + if (reclen > nbytes) + break; + if (memchr(dirent->name, '/', dirent->namelen) != NULL) + return -EIO; + + ctx->pos = dirent->off; + if (!dir_emit(ctx, dirent->name, dirent->namelen, dirent->ino, + dirent->type)) + break; + + buf += reclen; + nbytes -= reclen; + } + + return 0; +} + + +static int fuse_readdir_backing(struct fuse_args *fa, int *out, + struct file *file, struct dir_context *ctx, + bool *force_again, bool *allow_force, bool is_continued) +{ + struct fuse_file *ff = file->private_data; + struct file *backing_dir = ff->backing_file; + struct fuse_read_out *fro = fa->out_args[0].value; + struct extfuse_ctx ec; + + ec = (struct extfuse_ctx) { + .ctx.actor = filldir, + .ctx.pos = ctx->pos, + .addr = fa->out_args[1].value, + }; + + if (!ec.addr) + return -ENOMEM; + + if (!is_continued) + backing_dir->f_pos = file->f_pos; + + *out = iterate_dir(backing_dir, &ec.ctx); + if (ec.offset == 0) + *allow_force = false; + fa->out_args[1].size = ec.offset; + + fro->offset = ec.ctx.pos; + fro->again = false; + + return *out; +} + +static int fuse_readdir_finalize(struct fuse_args *fa, int *out, + struct file *file, struct dir_context *ctx, + bool *force_again, bool *allow_force, bool is_continued) +{ + struct fuse_read_out *fro = fa->out_args[0].value; + struct fuse_file *ff = file->private_data; + struct file *backing_dir = ff->backing_file; + + *out = parse_dirfile(fa->out_args[1].value, fa->out_args[1].size, ctx); + *force_again = !!fro->again; + if (*force_again && !*allow_force) + *out = -EINVAL; + + ctx->pos = fro->offset; + backing_dir->f_pos = fro->offset; + + free_page((unsigned long)fa->out_args[1].value); + return *out; +} + +int fuse_bpf_readdir(int *out, struct inode *inode, struct file *file, struct dir_context *ctx) +{ + int ret; + bool allow_force; + bool force_again = false; + bool is_continued = false; + +again: + ret = fuse_bpf_backing(inode, struct fuse_read_io, out, + fuse_readdir_initialize_in, fuse_readdir_initialize_out, + fuse_readdir_backing, fuse_readdir_finalize, + file, ctx, &force_again, &allow_force, is_continued); + if (force_again && *out >= 0) { + is_continued = true; + goto again; + } + + return ret; +} + static int fuse_access_initialize_in(struct fuse_args *fa, struct fuse_access_in *fai, struct inode *inode, int mask) { diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 25cedaa9014c..0ea3fb74caab 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -1414,6 +1414,7 @@ int fuse_bpf_file_read_iter(ssize_t *out, struct inode *inode, struct kiocb *ioc int fuse_bpf_file_write_iter(ssize_t *out, struct inode *inode, struct kiocb *iocb, struct iov_iter *from); int fuse_bpf_file_fallocate(int *out, struct inode *inode, struct file *file, int mode, loff_t offset, loff_t length); int fuse_bpf_lookup(struct dentry **out, struct inode *dir, struct dentry *entry, unsigned int flags); +int fuse_bpf_readdir(int *out, struct inode *inode, struct file *file, struct dir_context *ctx); int fuse_bpf_access(int *out, struct inode *inode, int mask); #else @@ -1484,6 +1485,11 @@ static inline int fuse_bpf_lookup(struct dentry **out, struct inode *dir, struct return 0; } +static inline int fuse_bpf_readdir(int *out, struct inode *inode, struct file *file, struct dir_context *ctx) +{ + return 0; +} + static inline int fuse_bpf_access(int *out, struct inode *inode, int mask) { return 0; diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c index e8deaacf1832..f32105679057 100644 --- a/fs/fuse/readdir.c +++ b/fs/fuse/readdir.c @@ -20,6 +20,8 @@ static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx) if (!fc->do_readdirplus) return false; + if (fi->nodeid == 0) + return false; if (!fc->readdirplus_auto) return true; if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state)) @@ -582,6 +584,9 @@ int fuse_readdir(struct file *file, struct dir_context *ctx) if (fuse_is_bad(inode)) return -EIO; + if (fuse_bpf_readdir(&err, inode, file, ctx)) + return err; + mutex_lock(&ff->readdir.lock); err = UNCACHED; diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index e49e5a8e044c..8c13483f240e 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -709,6 +709,12 @@ struct fuse_read_in { uint32_t padding; }; +struct fuse_read_out { + uint64_t offset; + uint32_t again; + uint32_t padding; +}; + #define FUSE_COMPAT_WRITE_IN_SIZE 24 struct fuse_write_in { -- 2.38.1.584.g0f3c55d4c2-goog