libfuse: add "clone_fd" option

This creates a separate device file descriptor for each processing thread,
which might improve performance.

diff --git a/ChangeLog b/ChangeLog
index 8a6576371c4d2124ba5057877ee5072e36dacd4a..4450ca5524109e3bf6ef02b99b839734320fe8b0 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,10 @@
        fuse_chan_get(), fuse_chan_put().  Removed function:
        fuse_chan_destroy().
 
+       * libfuse: add "clone_fd" option.  This creates a separate device
+       file descriptor for each processing thread, which might improve
+       performance.
+
 2015-04-23  Miklos Szeredi <miklos@szeredi.hu>
 
        * libfuse: add FUSE_CAP_NO_OPEN_SUPPORT flag to ->init()

diff --git a/include/fuse_kernel.h b/include/fuse_kernel.h
index 25084a052a1eff964d19a9683d5d6470590e4c7e..c9aca042e61d197927409531af4f8cdd88218adc 100644 (file)
--- a/include/fuse_kernel.h
+++ b/include/fuse_kernel.h
@@ -755,4 +755,7 @@ struct fuse_notify_retrieve_in {
        uint64_t        dummy4;
 };
 
+/* Device ioctls: */
+#define FUSE_DEV_IOC_CLONE     _IOR(229, 0, uint32_t)
+
 #endif /* _LINUX_FUSE_H */

diff --git a/lib/fuse_i.h b/lib/fuse_i.h
index 16adc69aa7cd6ac238f370bdf3684c673a2506f3..62af9f27ffd58f03078895b6314e2f373db82874 100644 (file)
--- a/lib/fuse_i.h
+++ b/lib/fuse_i.h
@@ -80,6 +80,7 @@ struct fuse_ll {
        int no_async_dio;
        int writeback_cache;
        int no_writeback_cache;
+       int clone_fd;
        struct fuse_lowlevel_ops op;
        int got_init;
        struct cuse_data *cuse_data;

diff --git a/lib/fuse_loop_mt.c b/lib/fuse_loop_mt.c
index 8f4dceb5f49a51dd1d85dd0f2c823cf47c2cc50e..6d7f051aa174ac0e010f992386a2ff8d5ea1d937 100755 (executable)
--- a/lib/fuse_loop_mt.c
+++ b/lib/fuse_loop_mt.c
@@ -20,6 +20,7 @@
 #include <semaphore.h>
 #include <errno.h>
 #include <sys/time.h>
+#include <sys/ioctl.h>
 
 /* Environment var controlling the thread stack size */
 #define ENVNAME_THREAD_STACK "FUSE_THREAD_STACK"
@@ -30,6 +31,7 @@ struct fuse_worker {
        pthread_t thread_id;
        size_t bufsize;
        struct fuse_buf fbuf;
+       struct fuse_chan *ch;
        struct fuse_mt *mt;
 };
 
@@ -74,7 +76,7 @@ static void *fuse_do_work(void *data)
                int res;
 
                pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
-               res = fuse_session_receive_buf(mt->se, &w->fbuf, mt->prevch);
+               res = fuse_session_receive_buf(mt->se, &w->fbuf, w->ch);
                pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
                if (res == -EINTR)
                        continue;
@@ -110,7 +112,7 @@ static void *fuse_do_work(void *data)
                        fuse_loop_start_thread(mt);
                pthread_mutex_unlock(&mt->lock);
 
-               fuse_session_process_buf(mt->se, &w->fbuf, mt->prevch);
+               fuse_session_process_buf(mt->se, &w->fbuf, w->ch);
 
                pthread_mutex_lock(&mt->lock);
                if (!isforget)
@@ -127,6 +129,7 @@ static void *fuse_do_work(void *data)
 
                        pthread_detach(w->thread_id);
                        free(w->fbuf.mem);
+                       fuse_chan_put(w->ch);
                        free(w);
                        return NULL;
                }
@@ -171,9 +174,46 @@ int fuse_start_thread(pthread_t *thread_id, void *(*func)(void *), void *arg)
        return 0;
 }
 
+static struct fuse_chan *fuse_clone_chan(struct fuse_mt *mt)
+{
+       int res;
+       int clonefd;
+       uint32_t masterfd;
+       struct fuse_chan *newch;
+       const char *devname = "/dev/fuse";
+
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+       clonefd = open(devname, O_RDWR | O_CLOEXEC);
+       if (clonefd == -1) {
+               fprintf(stderr, "fuse: failed to open %s: %s\n", devname,
+                       strerror(errno));
+               return NULL;
+       }
+       fcntl(clonefd, F_SETFD, FD_CLOEXEC);
+
+       masterfd = fuse_chan_fd(mt->prevch);
+       res = ioctl(clonefd, FUSE_DEV_IOC_CLONE, &masterfd);
+       if (res == -1) {
+               fprintf(stderr, "fuse: failed to clone device fd: %s\n",
+                       strerror(errno));
+               close(clonefd);
+               mt->se->f->clone_fd = 0;
+
+               return fuse_chan_get(mt->prevch);
+       }
+       newch = fuse_chan_new(clonefd);
+       if (newch == NULL)
+               close(clonefd);
+
+       return newch;
+}
+
 static int fuse_loop_start_thread(struct fuse_mt *mt)
 {
        int res;
+
        struct fuse_worker *w = malloc(sizeof(struct fuse_worker));
        if (!w) {
                fprintf(stderr, "fuse: failed to allocate worker structure\n");
@@ -183,8 +223,18 @@ static int fuse_loop_start_thread(struct fuse_mt *mt)
        w->fbuf.mem = NULL;
        w->mt = mt;
 
+
+       if (mt->se->f->clone_fd) {
+               w->ch = fuse_clone_chan(mt);
+               if (!w->ch)
+                       return -1;
+       } else {
+               w->ch = fuse_chan_get(mt->prevch);
+       }
+
        res = fuse_start_thread(&w->thread_id, fuse_do_work, w);
        if (res == -1) {
+               fuse_chan_put(w->ch);
                free(w);
                return -1;
        }
@@ -202,6 +252,7 @@ static void fuse_join_worker(struct fuse_mt *mt, struct fuse_worker *w)
        list_del_worker(w);
        pthread_mutex_unlock(&mt->lock);
        free(w->fbuf.mem);
+       fuse_chan_put(w->ch);
        free(w);
 }
 

diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index 8433e0a161e298753afe9add71acd106e3fe43b2..05103c08ffd1f95c447efcae2c86cd658583754d 100755 (executable)
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -2657,6 +2657,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
        { "writeback_cache", offsetof(struct fuse_ll, writeback_cache), 1},
        { "no_writeback_cache", offsetof(struct fuse_ll, no_writeback_cache), 1},
        { "time_gran=%u", offsetof(struct fuse_ll, conn.time_gran), 0 },
+       { "clone_fd", offsetof(struct fuse_ll, clone_fd), 1 },
        FUSE_OPT_KEY("max_read=", FUSE_OPT_KEY_DISCARD),
        FUSE_OPT_KEY("-h", KEY_HELP),
        FUSE_OPT_KEY("--help", KEY_HELP),
@@ -2693,6 +2694,7 @@ static void fuse_ll_help(void)
 "    -o [no_]async_dio        asynchronous direct I/O\n"
 "    -o [no_]writeback_cache  asynchronous, buffered writes\n"
 "    -o time_gran=N           time granularity in nsec\n"
+"    -o clone_fd              clone fuse device file descriptors\n"
 );
 }