diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/fuse_lowlevel.c | 77 | ||||
| -rw-r--r-- | lib/fuse_versionscript | 1 |
2 files changed, 78 insertions, 0 deletions
diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c index fc76b7c..a4a4df0 100644 --- a/lib/fuse_lowlevel.c +++ b/lib/fuse_lowlevel.c @@ -27,6 +27,7 @@ #include <errno.h> #include <assert.h> #include <sys/file.h> +#include <sys/ioctl.h> #ifndef F_LINUX_SPECIFIC_BASE #define F_LINUX_SPECIFIC_BASE 1024 @@ -388,6 +389,7 @@ static void fill_open(struct fuse_open_out *arg, const struct fuse_file_info *f) { arg->fh = f->fh; + arg->passthrough_fh = f->passthrough_fh; if (f->direct_io) arg->open_flags |= FOPEN_DIRECT_IO; if (f->keep_cache) @@ -457,6 +459,77 @@ int fuse_reply_canonical_path(fuse_req_t req, const char *path) return send_reply_ok(req, path, strlen(path) + 1); } +enum { + FUSE_PASSTHROUGH_API_UNAVAILABLE, + FUSE_PASSTHROUGH_API_V0, + FUSE_PASSTHROUGH_API_V1, + FUSE_PASSTHROUGH_API_V2, + FUSE_PASSTHROUGH_API_STABLE, +}; + +/* + * Requests the FUSE passthrough feature to be enabled on a specific file + * through the passed fd. + * This function returns an identifier that must be used as passthrough_fh + * when the open/create_open request reply is sent back to /dev/fuse. + * As for the current FUSE passthrough implementation, passthrough_fh values + * are only valid if > 0, so in case the FUSE passthrough open ioctl returns + * a value <= 0, this must be considered an error and is returned as-is by + * this function. + */ +int fuse_passthrough_enable(fuse_req_t req, unsigned int fd) { + static sig_atomic_t passthrough_version = FUSE_PASSTHROUGH_API_STABLE; + int ret = 0; /* values <= 0 represent errors in FUSE passthrough */ + + /* + * The interface of FUSE passthrough is still unstable in the kernel, + * so the following solution is to search for the most updated API + * version and, if not found, fall back to an older one. + * This happens when ioctl() returns -1 and errno is set to ENOTTY, + * an error code that corresponds to the lack of a specific ioctl. + */ + switch (passthrough_version) { + case FUSE_PASSTHROUGH_API_STABLE: + /* There is not a stable API yet */ + passthrough_version = FUSE_PASSTHROUGH_API_V2; + case FUSE_PASSTHROUGH_API_V2: { + ret = ioctl(req->se->fd, FUSE_DEV_IOC_PASSTHROUGH_OPEN_V2, &fd); + if (ret == -1 && errno == ENOTTY) + passthrough_version = FUSE_PASSTHROUGH_API_V1; + else + break; + } + case FUSE_PASSTHROUGH_API_V1: { + struct fuse_passthrough_out_v0 out = {}; + out.fd = fd; + + ret = ioctl(req->se->fd, FUSE_DEV_IOC_PASSTHROUGH_OPEN_V1, &out); + if (ret == -1 && errno == ENOTTY) + passthrough_version = FUSE_PASSTHROUGH_API_V0; + else + break; + } + case FUSE_PASSTHROUGH_API_V0: { + struct fuse_passthrough_out_v0 out = {}; + out.fd = fd; + + ret = ioctl(req->se->fd, FUSE_DEV_IOC_PASSTHROUGH_OPEN_V0, &out); + if (ret == -1 && errno == ENOTTY) + passthrough_version = FUSE_PASSTHROUGH_API_UNAVAILABLE; + else + break; + } + default: + fuse_log(FUSE_LOG_ERR, "fuse: passthrough_enable no valid API\n"); + return -ENOTTY; + } + + if (ret <= 0) + fuse_log(FUSE_LOG_ERR, "fuse: passthrough_enable: %s\n", strerror(errno)); + + return ret; +} + int fuse_reply_open(fuse_req_t req, const struct fuse_file_info *f) { struct fuse_open_out arg; @@ -1990,6 +2063,8 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg) bufsize = max_bufsize; } } + if (arg->flags & FUSE_PASSTHROUGH) + se->conn.capable |= FUSE_PASSTHROUGH; } else { se->conn.max_readahead = 0; } @@ -2102,6 +2177,8 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg) outarg.flags |= FUSE_WRITEBACK_CACHE; if (se->conn.want & FUSE_CAP_POSIX_ACL) outarg.flags |= FUSE_POSIX_ACL; + if (se->conn.want & FUSE_CAP_PASSTHROUGH) + outarg.flags |= FUSE_PASSTHROUGH; outarg.max_readahead = se->conn.max_readahead; outarg.max_write = se->conn.max_write; if (se->conn.proto_minor >= 13) { diff --git a/lib/fuse_versionscript b/lib/fuse_versionscript index 4c075a3..b01699a 100644 --- a/lib/fuse_versionscript +++ b/lib/fuse_versionscript @@ -163,6 +163,7 @@ FUSE_3.7 { global: fuse_set_log_func; fuse_log; + fuse_passthrough_enable; fuse_reply_canonical_path; } FUSE_3.3; |