Adds backing support for FUSE_READ and FUSE_WRITE This includes adjustments from Amir Goldstein's patch to FUSE Passthrough Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> Signed-off-by: Paul Lawrence <paullawrence@xxxxxxxxxx> --- fs/fuse/backing.c | 384 ++++++++++++++++++++++++++++++++++++++ fs/fuse/control.c | 2 +- fs/fuse/file.c | 8 + fs/fuse/fuse_i.h | 19 +- fs/fuse/inode.c | 13 ++ include/uapi/linux/fuse.h | 10 + 6 files changed, 434 insertions(+), 2 deletions(-) diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c index 567f859d300c..c813237b6599 100644 --- a/fs/fuse/backing.c +++ b/fs/fuse/backing.c @@ -11,6 +11,7 @@ #include <linux/file.h> #include <linux/fs_stack.h> #include <linux/namei.h> +#include <linux/uio.h> /* * expression statement to wrap the backing filter logic @@ -76,6 +77,95 @@ handled; \ }) +#define FUSE_BPF_IOCB_MASK (IOCB_APPEND | IOCB_DSYNC | IOCB_HIPRI | IOCB_NOWAIT | IOCB_SYNC) + +struct fuse_bpf_aio_req { + struct kiocb iocb; + refcount_t ref; + struct kiocb *iocb_orig; + struct timespec64 pre_atime; +}; + +static struct kmem_cache *fuse_bpf_aio_request_cachep; + +static void fuse_file_accessed(struct file *dst_file, struct file *src_file) +{ + struct inode *dst_inode; + struct inode *src_inode; + struct timespec64 dest_mtime, src_mtime, dst_ctime, src_ctime; + + if (dst_file->f_flags & O_NOATIME) + return; + + dst_inode = file_inode(dst_file); + src_inode = file_inode(src_file); + + dest_mtime = inode_get_mtime(dst_inode); + src_mtime = inode_get_mtime(src_inode); + dst_ctime = inode_get_ctime(dst_inode); + src_ctime = inode_get_ctime(src_inode); + if ((!timespec64_equal(&dest_mtime, &src_mtime) || + !timespec64_equal(&dst_ctime, &src_ctime))) { + inode_set_mtime_to_ts(dst_inode, src_mtime); + inode_set_ctime_to_ts(dst_inode, src_ctime); + } + + touch_atime(&dst_file->f_path); +} + +static void fuse_copyattr(struct file *dst_file, struct file *src_file) +{ + struct inode *dst = file_inode(dst_file); + struct inode *src = file_inode(src_file); + + inode_set_atime_to_ts(dst, inode_get_atime(src)); + inode_set_mtime_to_ts(dst, inode_get_mtime(src)); + inode_set_ctime_to_ts(dst, inode_get_ctime(src)); + i_size_write(dst, i_size_read(src)); + fuse_invalidate_attr(dst); +} + +static void fuse_file_start_write(struct file *fuse_file, struct file *backing_file, + loff_t pos, size_t count) +{ + struct inode *inode = file_inode(fuse_file); + struct fuse_inode *fi = get_fuse_inode(inode); + + if (inode->i_size < pos + count) + set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); + + file_start_write(backing_file); +} + +static void fuse_file_end_write(struct file *fuse_file, struct file *backing_file, + loff_t pos, size_t res) +{ + struct inode *inode = file_inode(fuse_file); + struct fuse_inode *fi = get_fuse_inode(inode); + + file_end_write(backing_file); + + if (res > 0) + fuse_write_update_attr(inode, pos, res); + + clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); + fuse_invalidate_attr(inode); +} + +static void fuse_file_start_read(struct file *backing_file, struct timespec64 *pre_atime) +{ + *pre_atime = inode_get_atime(file_inode(backing_file)); +} + +static void fuse_file_end_read(struct file *fuse_file, struct file *backing_file, + struct timespec64 *pre_atime) +{ + struct timespec64 atime = inode_get_atime(file_inode(backing_file)); + /* Mimic atime update policy of passthrough inode, not the value */ + if (!timespec64_equal(&atime, pre_atime)) + fuse_invalidate_atime(file_inode(fuse_file)); +} + static void fuse_get_backing_path(struct file *file, struct path *path) { path_get(&file->f_path); @@ -635,6 +725,284 @@ int fuse_bpf_lseek(loff_t *out, struct inode *inode, struct file *file, loff_t o file, offset, whence); } +static inline void fuse_bpf_aio_put(struct fuse_bpf_aio_req *aio_req) +{ + if (refcount_dec_and_test(&aio_req->ref)) + kmem_cache_free(fuse_bpf_aio_request_cachep, aio_req); +} + +static void fuse_bpf_aio_cleanup_handler(struct fuse_bpf_aio_req *aio_req, long res) +{ + struct kiocb *iocb = &aio_req->iocb; + struct kiocb *iocb_orig = aio_req->iocb_orig; + struct file *filp = iocb->ki_filp; + struct file *fuse_filp = iocb_orig->ki_filp; + + if (iocb->ki_flags & IOCB_WRITE) { + __sb_writers_acquired(file_inode(iocb->ki_filp)->i_sb, + SB_FREEZE_WRITE); + fuse_file_end_write(iocb_orig->ki_filp, iocb->ki_filp, iocb->ki_pos, res); + } else { + fuse_file_end_read(fuse_filp, filp, &aio_req->pre_atime); + } + iocb_orig->ki_pos = iocb->ki_pos; + fuse_bpf_aio_put(aio_req); +} + +static void fuse_bpf_aio_rw_complete(struct kiocb *iocb, long res) +{ + struct fuse_bpf_aio_req *aio_req = + container_of(iocb, struct fuse_bpf_aio_req, iocb); + struct kiocb *iocb_orig = aio_req->iocb_orig; + + fuse_bpf_aio_cleanup_handler(aio_req, res); + iocb_orig->ki_complete(iocb_orig, res); +} + +struct fuse_file_read_iter_args { + struct fuse_read_in in; + struct fuse_read_iter_out out; +}; + +static int fuse_file_read_iter_initialize_in(struct bpf_fuse_args *fa, struct fuse_file_read_iter_args *args, + struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct fuse_file *ff = file->private_data; + + args->in = (struct fuse_read_in) { + .fh = ff->fh, + .offset = iocb->ki_pos, + .size = to->count, + }; + + /* TODO we can't assume 'to' is a kvec */ + /* TODO we also can't assume the vector has only one component */ + *fa = (struct bpf_fuse_args) { + .info = (struct bpf_fuse_meta_info) { + .opcode = FUSE_READ, + .nodeid = ff->nodeid, + }, .in_numargs = 1, + .in_args[0].size = sizeof(args->in), + .in_args[0].value = &args->in, + /* + * TODO Design this properly. + * Possible approach: do not pass buf to bpf + * If going to userland, do a deep copy + * For extra credit, do that to/from the vector, rather than + * making an extra copy in the kernel + */ + }; + + return 0; +} + +static int fuse_file_read_iter_initialize_out(struct bpf_fuse_args *fa, struct fuse_file_read_iter_args *args, + struct kiocb *iocb, struct iov_iter *to) +{ + args->out = (struct fuse_read_iter_out) { + .ret = args->in.size, + }; + + fa->out_numargs = 1; + fa->out_args[0].size = sizeof(args->out); + fa->out_args[0].value = &args->out; + + return 0; +} + + +// TODO: use backing-file.c +static inline rwf_t fuse_iocb_to_rw_flags(int ifl, int iocb_mask) +{ + return ifl & iocb_mask; +} + +static int fuse_file_read_iter_backing(struct bpf_fuse_args *fa, ssize_t *out, + struct kiocb *iocb, struct iov_iter *to) +{ + struct fuse_read_iter_out *frio = fa->out_args[0].value; + struct file *file = iocb->ki_filp; + struct fuse_file *ff = file->private_data; + + if (!iov_iter_count(to)) + return 0; + + if ((iocb->ki_flags & IOCB_DIRECT) && + (!ff->backing_file->f_mapping->a_ops || + !ff->backing_file->f_mapping->a_ops->direct_IO)) + return -EINVAL; + + /* TODO This just plain ignores any change to fuse_read_in */ + if (is_sync_kiocb(iocb)) { + struct timespec64 pre_atime; + + fuse_file_start_read(ff->backing_file, &pre_atime); + *out = vfs_iter_read(ff->backing_file, to, &iocb->ki_pos, + fuse_iocb_to_rw_flags(iocb->ki_flags, FUSE_BPF_IOCB_MASK)); + fuse_file_end_read(file, ff->backing_file, &pre_atime); + } else { + struct fuse_bpf_aio_req *aio_req; + + *out = -ENOMEM; + aio_req = kmem_cache_zalloc(fuse_bpf_aio_request_cachep, GFP_KERNEL); + if (!aio_req) + goto out; + + aio_req->iocb_orig = iocb; + fuse_file_start_read(ff->backing_file, &aio_req->pre_atime); + kiocb_clone(&aio_req->iocb, iocb, ff->backing_file); + aio_req->iocb.ki_complete = fuse_bpf_aio_rw_complete; + refcount_set(&aio_req->ref, 2); + *out = vfs_iocb_iter_read(ff->backing_file, &aio_req->iocb, to); + fuse_bpf_aio_put(aio_req); + if (*out != -EIOCBQUEUED) + fuse_bpf_aio_cleanup_handler(aio_req, *out); + } + + frio->ret = *out; + + /* TODO Need to point value at the buffer for post-modification */ + +out: + fuse_file_accessed(file, ff->backing_file); + + return *out; +} + +static int fuse_file_read_iter_finalize(struct bpf_fuse_args *fa, ssize_t *out, + struct kiocb *iocb, struct iov_iter *to) +{ + struct fuse_read_iter_out *frio = fa->out_args[0].value; + + *out = frio->ret; + + return 0; +} + +int fuse_bpf_file_read_iter(ssize_t *out, struct inode *inode, struct kiocb *iocb, struct iov_iter *to) +{ + return bpf_fuse_backing(inode, struct fuse_file_read_iter_args, out, + fuse_file_read_iter_initialize_in, + fuse_file_read_iter_initialize_out, + fuse_file_read_iter_backing, + fuse_file_read_iter_finalize, + iocb, to); +} + +struct fuse_file_write_iter_args { + struct fuse_write_in in; + struct fuse_write_iter_out out; +}; + +static int fuse_file_write_iter_initialize_in(struct bpf_fuse_args *fa, + struct fuse_file_write_iter_args *args, + struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct fuse_file *ff = file->private_data; + + *args = (struct fuse_file_write_iter_args) { + .in.fh = ff->fh, + .in.offset = iocb->ki_pos, + .in.size = from->count, + }; + + /* TODO we can't assume 'from' is a kvec */ + *fa = (struct bpf_fuse_args) { + .info = (struct bpf_fuse_meta_info) { + .opcode = FUSE_WRITE, + .nodeid = ff->nodeid, + }, + .in_numargs = 1, + .in_args[0].size = sizeof(args->in), + .in_args[0].value = &args->in, + }; + + return 0; +} + +static int fuse_file_write_iter_initialize_out(struct bpf_fuse_args *fa, + struct fuse_file_write_iter_args *args, + struct kiocb *iocb, struct iov_iter *from) +{ + /* TODO we can't assume 'from' is a kvec */ + fa->out_numargs = 1; + fa->out_args[0].size = sizeof(args->out); + fa->out_args[0].value = &args->out; + + return 0; +} + +static int fuse_file_write_iter_backing(struct bpf_fuse_args *fa, ssize_t *out, + struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct fuse_file *ff = file->private_data; + struct fuse_write_iter_out *fwio = fa->out_args[0].value; + ssize_t count = iov_iter_count(from); + + if (!count) + return 0; + + /* TODO This just plain ignores any change to fuse_write_in */ + /* TODO uint32_t seems smaller than ssize_t.... right? */ + inode_lock(file_inode(file)); + + fuse_copyattr(file, ff->backing_file); + + if (is_sync_kiocb(iocb)) { + fuse_file_start_write(file, ff->backing_file, iocb->ki_pos, count); + *out = vfs_iter_write(ff->backing_file, from, &iocb->ki_pos, + fuse_iocb_to_rw_flags(iocb->ki_flags, FUSE_BPF_IOCB_MASK)); + fuse_file_end_write(file, ff->backing_file, iocb->ki_pos, *out); + } else { + struct fuse_bpf_aio_req *aio_req; + + *out = -ENOMEM; + aio_req = kmem_cache_zalloc(fuse_bpf_aio_request_cachep, GFP_KERNEL); + if (!aio_req) + goto out; + + fuse_file_start_write(file, ff->backing_file, iocb->ki_pos, count); + __sb_writers_release(file_inode(ff->backing_file)->i_sb, SB_FREEZE_WRITE); + aio_req->iocb_orig = iocb; + kiocb_clone(&aio_req->iocb, iocb, ff->backing_file); + aio_req->iocb.ki_complete = fuse_bpf_aio_rw_complete; + refcount_set(&aio_req->ref, 2); + *out = vfs_iocb_iter_write(ff->backing_file, &aio_req->iocb, from); + fuse_bpf_aio_put(aio_req); + if (*out != -EIOCBQUEUED) + fuse_bpf_aio_cleanup_handler(aio_req, *out); + } + +out: + inode_unlock(file_inode(file)); + fwio->ret = *out; + if (*out < 0) + return *out; + return 0; +} + +static int fuse_file_write_iter_finalize(struct bpf_fuse_args *fa, ssize_t *out, + struct kiocb *iocb, struct iov_iter *from) +{ + struct fuse_write_iter_out *fwio = fa->out_args[0].value; + + *out = fwio->ret; + return 0; +} + +int fuse_bpf_file_write_iter(ssize_t *out, struct inode *inode, struct kiocb *iocb, struct iov_iter *from) +{ + return bpf_fuse_backing(inode, struct fuse_file_write_iter_args, out, + fuse_file_write_iter_initialize_in, + fuse_file_write_iter_initialize_out, + fuse_file_write_iter_backing, + fuse_file_write_iter_finalize, + iocb, from); +} + ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma) { int ret; @@ -1335,3 +1703,19 @@ int fuse_bpf_access(int *out, struct inode *inode, int mask) fuse_access_initialize_in, fuse_access_initialize_out, fuse_access_backing, fuse_access_finalize, inode, mask); } + +int __init fuse_bpf_init(void) +{ + fuse_bpf_aio_request_cachep = kmem_cache_create("fuse_bpf_aio_req", + sizeof(struct fuse_bpf_aio_req), + 0, SLAB_HWCACHE_ALIGN, NULL); + if (!fuse_bpf_aio_request_cachep) + return -ENOMEM; + + return 0; +} + +void __exit fuse_bpf_cleanup(void) +{ + kmem_cache_destroy(fuse_bpf_aio_request_cachep); +} diff --git a/fs/fuse/control.c b/fs/fuse/control.c index 284a35006462..3e1d183b6c60 100644 --- a/fs/fuse/control.c +++ b/fs/fuse/control.c @@ -378,7 +378,7 @@ int __init fuse_ctl_init(void) return register_filesystem(&fuse_ctl_fs_type); } -void __exit fuse_ctl_cleanup(void) +void fuse_ctl_cleanup(void) { unregister_filesystem(&fuse_ctl_fs_type); } diff --git a/fs/fuse/file.c b/fs/fuse/file.c index c43f2d61c41a..3443510027a5 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1646,6 +1646,7 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to) struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct inode *inode = file_inode(file); + ssize_t ret; if (fuse_is_bad(inode)) return -EIO; @@ -1653,6 +1654,9 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to) if (FUSE_IS_DAX(inode)) return fuse_dax_read_iter(iocb, to); + if (fuse_bpf_file_read_iter(&ret, inode, iocb, to)) + return ret; + if (!(ff->open_flags & FOPEN_DIRECT_IO)) return fuse_cache_read_iter(iocb, to); else @@ -1664,6 +1668,7 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from) struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct inode *inode = file_inode(file); + ssize_t ret = 0; if (fuse_is_bad(inode)) return -EIO; @@ -1671,6 +1676,9 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from) if (FUSE_IS_DAX(inode)) return fuse_dax_write_iter(iocb, from); + if (fuse_bpf_file_write_iter(&ret, inode, iocb, from)) + return ret; + if (!(ff->open_flags & FOPEN_DIRECT_IO)) return fuse_cache_write_iter(iocb, from); else diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 9b176f78999f..bd187dbf20b2 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -1164,7 +1164,7 @@ int fuse_dev_init(void); void fuse_dev_cleanup(void); int fuse_ctl_init(void); -void __exit fuse_ctl_cleanup(void); +void fuse_ctl_cleanup(void); /** * Simple request sending that does request allocation and freeing @@ -1448,6 +1448,8 @@ int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *entry); int fuse_bpf_release(int *out, struct inode *inode, struct fuse_file *ff); int fuse_bpf_releasedir(int *out, struct inode *inode, struct fuse_file *ff); int fuse_bpf_lseek(loff_t *out, struct inode *inode, struct file *file, loff_t offset, int whence); +int fuse_bpf_file_read_iter(ssize_t *out, struct inode *inode, struct kiocb *iocb, struct iov_iter *to); +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_access(int *out, struct inode *inode, int mask); @@ -1500,6 +1502,16 @@ static inline int fuse_bpf_lseek(loff_t *out, struct inode *inode, struct file * return 0; } +static inline int fuse_bpf_file_read_iter(ssize_t *out, struct inode *inode, struct kiocb *iocb, struct iov_iter *to) +{ + return 0; +} + +static inline int fuse_bpf_file_write_iter(ssize_t *out, struct inode *inode, struct kiocb *iocb, struct iov_iter *from) +{ + return 0; +} + static inline int fuse_bpf_file_fallocate(int *out, struct inode *inode, struct file *file, int mode, loff_t offset, loff_t length) { return 0; @@ -1523,4 +1535,9 @@ int fuse_handle_backing(struct fuse_bpf_entry *fbe, struct path *backing_path); int fuse_revalidate_backing(struct dentry *entry, unsigned int flags); +#ifdef CONFIG_FUSE_BPF +int __init fuse_bpf_init(void); +void __exit fuse_bpf_cleanup(void); +#endif /* CONFIG_FUSE_BPF */ + #endif /* _FS_FUSE_I_H */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index b47b2e41e5e4..825b65117126 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -2199,11 +2199,21 @@ static int __init fuse_init(void) if (res) goto err_sysfs_cleanup; +#ifdef CONFIG_FUSE_BPF + res = fuse_bpf_init(); + if (res) + goto err_ctl_cleanup; +#endif + sanitize_global_limit(&max_user_bgreq); sanitize_global_limit(&max_user_congthresh); return 0; +#ifdef CONFIG_FUSE_BPF + err_ctl_cleanup: + fuse_ctl_cleanup(); +#endif err_sysfs_cleanup: fuse_sysfs_cleanup(); err_dev_cleanup: @@ -2221,6 +2231,9 @@ static void __exit fuse_exit(void) fuse_ctl_cleanup(); fuse_sysfs_cleanup(); fuse_fs_cleanup(); +#ifdef CONFIG_FUSE_BPF + fuse_bpf_cleanup(); +#endif fuse_dev_cleanup(); } diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index 74bc15e1d0b7..8efaa9eecc5f 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -811,6 +811,11 @@ struct fuse_read_in { uint32_t padding; }; +// This is likely not what we want +struct fuse_read_iter_out { + uint64_t ret; +}; + #define FUSE_COMPAT_WRITE_IN_SIZE 24 struct fuse_write_in { @@ -828,6 +833,11 @@ struct fuse_write_out { uint32_t padding; }; +// This is likely not what we want +struct fuse_write_iter_out { + uint64_t ret; +}; + #define FUSE_COMPAT_STATFS_SIZE 48 struct fuse_statfs_out { -- 2.44.0.478.gd926399ef9-goog