Released 3.2.0

Not supported on OS X, and not strictly necessary.

Fixes: #64.

.travis.yml

@@ -1,6 +1,5 @@
 sudo: required
 dist: trusty
-group: deprecated-2017Q2
 
 language:
     - c
@@ -13,6 +12,8 @@ addons:
     - clang
     - gcc
     - gcc-6
+before_install:
+   - pip install pip==8.1.1 && pip3 install pip==8.1.1
 install: test/travis-install.sh
 script: test/travis-build.sh
 

AUTHORS

@@ -21,6 +21,7 @@ Bill Zissimopoulos <billziss@navimatics.com>
 Chris Wolfe <cwolfe@chromium.org>
 gala <gala132@users.noreply.github.com>
 George Vlahavas <vlahavas@gmail.com>
+harrim4n <git@harrim4n.com>
 Jakub Jelen <jjelen@redhat.com>
 Julio Merino <jmmv@google.com>
 Julio Merino <jmmv@meroh.net>

ChangeLog.rst

@@ -1,3 +1,22 @@
+Release 3.2.0 (2017-08-06)
+--------------------------
+
+* Re-enabled writeback cache.
+* SSHFS now supports O_APPEND.
+
+Release 3.1.0 (2017-08-04)
+--------------------------
+
+* Temporarily disabled the writeback cache feature, since there
+  have been reports of dataloss when appending to files when
+  writeback caching is enabled.
+
+* Fixed a crash due to a race condition when listing
+  directory contents.
+
+* For improved backwards compatibility, SSHFS now also silently
+  accepts the old ``-o cache_*`` options.
+  
 Release 3.0.0 (2017-07-08)
 --------------------------
 

FAQ

@@ -6,30 +6,26 @@ SSHFS FAQ
 2.     Advantage of sshfs over NFS and Samba
 3.     Create the device node
 4.     mv fails with "Operation not permitted"
-5.     cvs fails with "cvs [status aborted]: cannot get working
-       directory: No such file or directory" in a sshfs mounted directory
-6.     Changes on the server are not immediately visible in the
-       mounted directory.
-7.     Configuring the ssh connection
-8.     What are the no_readahead and sshfs_sync options for?
-9.    Why does df return strange values on partitions mounted via
+5.     Configuring the ssh connection
+6.     What are the no_readahead and sshfs_sync options for?
+7.     Why does df return strange values on partitions mounted via
        sshfs?
-10.    How do I specify the remote mount point (since the example
+8.     How do I specify the remote mount point (since the example
        defaults to the home directory)
-11.    sshfs hangs after a while
-12.    Following symlinks on the server side
-13.    Making absolute symlinks work
-14.    Mounting as root
-15.    Exporting via NFS
-16.    Automatical mounting using /etc/fstab
-17.    Why does SVN (etc...) fail with permission denied?
-18.    Why does SVN (etc...) fail to rename files?
-19.    Is there some neat way to do it in reverse?
-20.    Might it be reasonable to disallow loops?
-21.    How to mount through an intermediary ssh server, eg:
+9.     sshfs hangs after a while
+10.    Following symlinks on the server side
+11.    Making absolute symlinks work
+12.    Mounting as root
+13.    Exporting via NFS
+14.    Automatical mounting using /etc/fstab
+15.    Why does SVN (etc...) fail with permission denied?
+16.    Why does SVN (etc...) fail to rename files?
+17.    Is there some neat way to do it in reverse?
+18.    Might it be reasonable to disallow loops?
+19.    How to mount through an intermediary ssh server, eg:
        localhost -> A -> B; mount B from localhost
-22.    Alternative Solution
-23.    I seem to have successfully mounted a remote directory, but
+20.    Alternative Solution
+21.    I seem to have successfully mounted a remote directory, but
        performing an `ls -l` on the directory above the mount point shows
        the mount point's attributes as `? ? ? ? ? ?`. Nothing shows up in
        the directory either. What am I doing wrong?
@@ -82,80 +78,63 @@ SSHFS FAQ
 
    Use -o workaround=rename (requires sshfs version >= 1.3).
 
-5. cvs fails with "cvs status aborted?: cannot get working directory: No such
-   file or directory" in a sshfs mounted directory
-
-   Use the -oreaddir_ino option. Example:
-     sshfs -oreaddir_ino hostname:remote_dir mount_point
-
-6. Changes on the server are not immediately visible in the mounted directory.
-
-   By default, sshfs caches things for 20 seconds, use -o cache_timeout=N
-   to change the default cache timeout (in seconds) or -o cache=no for
-   disabling the cache.
-
-   You can also control cache timeouts for directory listing etc with
-   -o cache_stat_timeout=N,
-   -o cache_dir_timout=N, and
-   -o cache_link_timout=N.
-
-7. Configuring the ssh connection
+5. Configuring the ssh connection
 
    In addition to flags like -C, -p, and -o SSHOPT...=, you may find it
    easier to edit your /.ssh/config file. You can add an entry with any
    customization you want, test it with ssh, and finally use it with
    sshfs. As a bonus, you get a short mnemonic for your configuration.
 
-8. What are the no_readahead and sshfs_sync options for?
+6. What are the no_readahead and sshfs_sync options for?
 
    These disable read and write optimizations respectively. They don't
    really make sense unless you're doing something special.
 
-9. Why does df return strange values on partitions mounted via sshfs?
+7. Why does df return strange values on partitions mounted via sshfs?
 
    Because the SFTP protocol doesn't have a statfs operation this is
    currently not possible to display proper usage on remote partition.
 
-10. How do I specfy the remote mount point (since the example defaults to the
-    home directory)
+8. How do I specfy the remote mount point (since the example defaults to the
+   home directory)
 
-    The example shows:
-      sshfs hostname: mountpoint
+   The example shows:
+     sshfs hostname: mountpoint
 
-    To specify a remote mount point use:
-      sshfs hostname:remotemountpoint mountpoint
+   To specify a remote mount point use:
+     sshfs hostname:remotemountpoint mountpoint
 
-    This might be obvious to others, but I ended up looking up the
-    interface to sftp to see if I could learn how to specify the remote
-    mount point, then thought about the way that scp specifies the remote
-    directory, and it worked.
+   This might be obvious to others, but I ended up looking up the
+   interface to sftp to see if I could learn how to specify the remote
+   mount point, then thought about the way that scp specifies the remote
+   directory, and it worked.
 
-11. sshfs hangs after a while
+9. sshfs hangs after a while
 
-    Mounting works fine, I can use the files in Mountpoint as good as any
-    other files on my system, but after bit of time, changing nothing on
-    the remote files sshfs crashes. This means, I can not cd into the
-    Mountpoint (xterm hangs, nautilus hangs... every program trying to
-    access the Mountpoint gets stuck, and won't return).
+   Mounting works fine, I can use the files in Mountpoint as good as any
+   other files on my system, but after bit of time, changing nothing on
+   the remote files sshfs crashes. This means, I can not cd into the
+   Mountpoint (xterm hangs, nautilus hangs... every program trying to
+   access the Mountpoint gets stuck, and won't return).
 
-    Solution: add
-      ServerAliveInterval 15
+   Solution: add
+     ServerAliveInterval 15
 
-    in your .ssh/config (or use -o ServerAliveInterval=15 on the sshfs
-    command line but I did not test that solution). This will force the
-    ssh connection to stay alive even if you have no activity.
+   in your .ssh/config (or use -o ServerAliveInterval=15 on the sshfs
+   command line but I did not test that solution). This will force the
+   ssh connection to stay alive even if you have no activity.
 
-12. Following symlinks on the server side
+10. Following symlinks on the server side
 
     The -o follow_symlinks option will enable this.
 
-13. Making absolute symlinks work
+11. Making absolute symlinks work
 
     Use the -o transform_symlinks option, which will transform absolute
     symlinks (ones which point somewhere inside the mount) into relative
     ones.
 
-14. Mounting as root
+12. Mounting as root
 
     Generally it's not possible to use an sshfs mount as a "real"
     filesystem shared between multiple users. Some of this functionality
@@ -163,11 +142,11 @@ SSHFS FAQ
     options, but files will not be created with the correct ownership,
     etc...
 
-15. Exporting via NFS
+13. Exporting via NFS
 
     Use the userspace NFS daemon http://sourceforge.net/projects/unfs
 
-16. Automatical mounting using /etc/fstab
+14. Automatical mounting using /etc/fstab
 
     A line in /etc/fstab has the following format:
       sshfs#USERNAME@REMOTE_HOST:REMOTE_PATH MOUNT_POINT fuse SSHFS_OPTIONS 0 0
@@ -176,7 +155,7 @@ SSHFS FAQ
       sshfs#guest@guest.login.com:data /mnt/guest fuse \
         uid=1003,gid=100,umask=0,allow_other 0 0
 
-17. Why does SVN (etc...) fail with permission denied?
+15. Why does SVN (etc...) fail with permission denied?
 
     This is a bug that happens when an application creates a read-only
     file opened for writing (e.g. open("foo", O_WRONLY|O_CREAT, 0444))
@@ -184,7 +163,7 @@ SSHFS FAQ
     It has been fixed in sshfs version 1.3, but also requires FUSE version
     >=2.5.X and Linux kernel version >=2.6.15.
 
-18. Why does SVN (etc...) fail to rename files?
+16. Why does SVN (etc...) fail to rename files?
 
     $ svn co svn://anonsvn.kde.org/home/kde/trunk/KDE/kdelibs
     svn: Can't move 'kdelibs/.svn/tmp/entries' to 'kdelibs/.svn/entries':
@@ -200,7 +179,7 @@ SSHFS FAQ
     semantics, but it cannot guarantee atomicity. In most of the cases
     this doesn't matter, and things will work fine with this option.
 
-19. Is there some neat way to do it in reverse?
+17. Is there some neat way to do it in reverse?
 
     You want to mount a USB thumb drive onto a file server that is rather
     remote.
@@ -214,13 +193,13 @@ SSHFS FAQ
     (Now, is there is there a smarter way that does not involve port
     opening login permissions in an undesireable direction?)
 
-20. Might it be reasonable to disallow loops?
+18. Might it be reasonable to disallow loops?
 
     sshfs localhost:/mnt /mnt
 
     This seems to produce undesirable results. --JoshuaRodman
 
-21. How to mount through an intermediary ssh server, eg: localhost -> A -> B;
+19. How to mount through an intermediary ssh server, eg: localhost -> A -> B;
     mount B from localhost
 
     Start by mounting the folder you need that is on "a" to a folder on
@@ -230,7 +209,7 @@ SSHFS FAQ
     A mounts B:/home/x on /mnt/Bx
     localhost mounts A:/mnt/Bx on ~/mydir
 
-22. Alternative Solution:
+20. Alternative Solution:
 
     1) Create a shell script to wrap the tunneling of one ssh command over
     another,
@@ -244,7 +223,7 @@ SSHFS FAQ
     normal but using this script as the ssh command.
       $ sshfs -o ssh_command='Atunnel' B: ~/mydir
 
-23. I seem to have successfully mounted a remote directory, but performing an
+21. I seem to have successfully mounted a remote directory, but performing an
     `ls -l` on the directory above the mount point shows the mount point's
     attributes as `? ? ? ? ? ?`. Nothing shows up in the directory either. What
     am I doing wrong?

Makefile.am

@@ -17,7 +17,7 @@ sshfs_CFLAGS = $(SSHFS_CFLAGS)
 sshfs_CPPFLAGS = -D_REENTRANT -DFUSE_USE_VERSION=31 -DLIBDIR=\"$(libdir)\" \
                  -DIDMAP_DEFAULT="\"$(IDMAP_DEFAULT)\""
 
-EXTRA_DIST = sshfs.1.in meson.build
+EXTRA_DIST = sshfs.1.in meson.build ChangeLog.rst
 CLEANFILES = sshfs.1 sshfs.1.tmp
 
 dist_man_MANS = sshfs.1

README.rst

@@ -116,6 +116,16 @@ individual files when seen through an SSHFS mount, i.e. they will
 appear to have different inodes and an *st_nlink* value of 1.
 
 
+O_APPEND
+~~~~~~~~
+
+When writeback caching is enabled, SSHFS cannot reliably support the
+``O_APPEND`` open flag and thus signals an error on open.  To enable
+support for unreliable ``O_APPEND`` (which may overwrite data if the
+file changes on the server at a bad time), mount the file system with
+``-o unreliable_append``.
+
+
 Getting Help
 ------------
 

cache.c

@@ -586,6 +586,19 @@ static const struct fuse_opt cache_opts[] = {
 					       clean_interval_secs), 0 },
 	{ "dcache_min_clean_interval=%u", offsetof(struct cache,
 						   min_clean_interval_secs), 0 },
+
+	/* For backwards compatibility */
+	{ "cache_timeout=%u", offsetof(struct cache, stat_timeout_secs), 0 },
+	{ "cache_timeout=%u", offsetof(struct cache, dir_timeout_secs), 0 },
+	{ "cache_timeout=%u", offsetof(struct cache, link_timeout_secs), 0 },
+	{ "cache_stat_timeout=%u", offsetof(struct cache, stat_timeout_secs), 0 },
+	{ "cache_dir_timeout=%u", offsetof(struct cache, dir_timeout_secs), 0 },
+	{ "cache_link_timeout=%u", offsetof(struct cache, link_timeout_secs), 0 },
+	{ "cache_max_size=%u", offsetof(struct cache, max_size), 0 },
+	{ "cache_clean_interval=%u", offsetof(struct cache,
+					       clean_interval_secs), 0 },
+	{ "cache_min_clean_interval=%u", offsetof(struct cache,
+						   min_clean_interval_secs), 0 },
 	FUSE_OPT_END
 };
 

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT(sshfs, 3.0.0)
+AC_INIT(sshfs, 3.2.0)
 AC_CANONICAL_TARGET
 AM_INIT_AUTOMAKE([foreign subdir-objects])
 AM_CONFIG_HEADER(config.h)

meson.build

@@ -1,4 +1,4 @@
-project('sshfs', 'c', version: '3.0.0',
+project('sshfs', 'c', version: '3.1.0',
         meson_version: '>= 0.38',
         default_options: [ 'buildtype=plain' ])
 

sshfs.1.in

@@ -64,15 +64,6 @@ synchronous readdir
 \fB\-o\fR sshfs_debug
 print some debugging information
 .TP
-\fB\-o\fR cache=BOOL
-enable caching {yes,no} (default: yes)
-.TP
-\fB\-o\fR cache_timeout=N
-sets timeout for caches in seconds (default: 20)
-.TP
-\fB\-o\fR cache_X_timeout=N
-sets timeout for {stat,dir,link} cache
-.TP
 \fB\-o\fR workaround=LIST
 colon separated list of workarounds
 .RS 8
@@ -80,9 +71,6 @@ colon separated list of workarounds
 none
 no workarounds enabled
 .TP
-all
-all workarounds enabled
-.TP
 [no]rename
 fix renaming to existing file (default: off)
 .TP
@@ -180,9 +168,6 @@ allow access to other users
 .TP
 \fB\-o\fR allow_root
 allow access to root
-.TP
-\fB\-o\fR nonempty
-allow mounts over non\-empty file/dir
 .HP
 \fB\-o\fR default_permissions
 enable permission checking by kernel
@@ -193,24 +178,9 @@ set filesystem name
 \fB\-o\fR subtype=NAME
 set filesystem type
 .TP
-\fB\-o\fR large_read
-issue large read requests (2.4 only)
-.TP
 \fB\-o\fR max_read=N
 set maximum size of read requests
 .TP
-\fB\-o\fR hard_remove
-immediate removal (don't hide files)
-.TP
-\fB\-o\fR use_ino
-let filesystem set inode numbers
-.TP
-\fB\-o\fR readdir_ino
-try to fill in d_ino in readdir
-.TP
-\fB\-o\fR direct_io
-use direct I/O
-.TP
 \fB\-o\fR kernel_cache
 cache files in kernel
 .TP
@@ -238,26 +208,11 @@ cache timeout for attributes (1.0s)
 \fB\-o\fR ac_attr_timeout=T
 auto cache timeout for attributes (attr_timeout)
 .TP
-\fB\-o\fR intr
-allow requests to be interrupted
-.TP
-\fB\-o\fR intr_signal=NUM
-signal to send on interrupt (10)
-.TP
 \fB\-o\fR modules=M1[:M2...]
 names of modules to push onto filesystem stack
 .TP
 \fB\-o\fR max_write=N
 set maximum size of write requests
-.TP
-\fB\-o\fR max_readahead=N
-set maximum readahead
-.TP
-\fB\-o\fR async_read
-perform reads asynchronously (default)
-.TP
-\fB\-o\fR sync_read
-perform reads synchronously
 .SS "Module options:"
 .TP
 [subdir]

sshfs.c

@@ -216,6 +216,7 @@ struct sshfs {
 	int rename_workaround;
 	int truncate_workaround;
 	int buflimit_workaround;
+	int unrel_append;
 	int fstat_workaround;
 	int transform_symlinks;
 	int follow_symlinks;
@@ -279,7 +280,6 @@ struct sshfs {
 	int ext_statvfs;
 	int ext_hardlink;
 	int ext_fsync;
-	mode_t mnt_mode;
 	struct fuse_operations *op;
 
 	/* statistics */
@@ -410,6 +410,7 @@ static struct fuse_opt sshfs_opts[] = {
 	SSHFS_OPT("dir_cache=no",  dir_cache, 0),
 	SSHFS_OPT("writeback_cache=yes", writeback_cache, 1),
 	SSHFS_OPT("writeback_cache=no", writeback_cache, 0),
+	SSHFS_OPT("unreliable_append", unrel_append, 1),
 
 	SSHFS_OPT("-h",		show_help, 1),
 	SSHFS_OPT("--help",	show_help, 1),
@@ -423,7 +424,13 @@ static struct fuse_opt sshfs_opts[] = {
 	FUSE_OPT_KEY("-p ",            KEY_PORT),
 	FUSE_OPT_KEY("-C",             KEY_COMPRESS),
 	FUSE_OPT_KEY("-F ",            KEY_CONFIGFILE),
+
+	/* For backwards compatibility */
+	SSHFS_OPT("cache=yes", dir_cache, 1),
+	SSHFS_OPT("cache=no",  dir_cache, 0),
+	
 	FUSE_OPT_END
+
 };
 
 static struct fuse_opt workaround_opts[] = {
@@ -1644,16 +1651,11 @@ static int sftp_check_root(const char *base_path)
 	if (!(flags & SSH_FILEXFER_ATTR_PERMISSIONS))
 		goto out;
 
-	if (S_ISDIR(sshfs.mnt_mode) && !S_ISDIR(stbuf.st_mode)) {
+	if (!S_ISDIR(stbuf.st_mode)) {
 		fprintf(stderr, "%s:%s: Not a directory\n", sshfs.host,
 			remote_dir);
 		goto out;
 	}
-	if ((sshfs.mnt_mode ^ stbuf.st_mode) & S_IFMT) {
-		fprintf(stderr, "%s:%s: type of file differs from mountpoint\n",
-			sshfs.host, remote_dir);
-		goto out;
-	}
 
 	err = 0;
 
@@ -2073,11 +2075,16 @@ static int sftp_readdir_async(struct buffer *handle, void *buf, off_t offset,
 			outstanding--;
 
 			if (done) {
+				/* We need to cache want_reply, since processing
+				   thread may free req right after unlock() if
+				   want_reply == 0 */
+				int want_reply;
 				pthread_mutex_lock(&sshfs.lock);
 				if (sshfs_req_pending(req))
 					req->want_reply = 0;
+				want_reply = req->want_reply;
 				pthread_mutex_unlock(&sshfs.lock);
-				if (!req->want_reply)
+				if (!want_reply)
 					continue;
 			}
 
@@ -2490,11 +2497,29 @@ static int sshfs_open_common(const char *path, mode_t mode,
 	uint32_t pflags = 0;
 	struct iovec iov;
 	uint8_t type;
-	uint64_t wrctr;
+	uint64_t wrctr = 0;
 
 	if (sshfs.dir_cache)
 		wrctr = cache_get_write_ctr();
 
+	/* With writeback cache, kernel may send read requests even
+	   when userspace opened write-only */
+	if (sshfs.writeback_cache &&
+	    (fi->flags & O_ACCMODE) == O_WRONLY) {
+		fi->flags &= ~O_ACCMODE;
+		fi->flags |= O_RDWR;
+	}
+
+	/* Having the kernel handle O_APPEND doesn't work reliably, if
+	   the file changes on the server at the wrong time, we will
+	   overwrite data instead of appending. */
+	if ((fi->flags & O_APPEND) && sshfs.writeback_cache) {
+		if(sshfs.unrel_append)
+			fi->flags &= ~O_APPEND;
+		else
+			return -EINVAL;
+	}
+
 	if ((fi->flags & O_ACCMODE) == O_RDONLY)
 		pflags = SSH_FXF_READ;
 	else if((fi->flags & O_ACCMODE) == O_WRONLY)
@@ -2513,6 +2538,9 @@ static int sshfs_open_common(const char *path, mode_t mode,
 	if (fi->flags & O_TRUNC)
 		pflags |= SSH_FXF_TRUNC;
 
+	if (fi->flags & O_APPEND)
+		pflags |= SSH_FXF_APPEND;
+	
 	sf = g_new0(struct sshfs_file, 1);
 	list_init(&sf->write_reqs);
 	pthread_cond_init(&sf->write_finished, NULL);
@@ -3145,6 +3173,9 @@ static int sshfs_getattr(const char *path, struct stat *stbuf,
 	}		
 	if (!err) {
 		err = buf_get_attrs(&outbuf, stbuf, NULL);
+#ifdef __APPLE__
+		stbuf->st_blksize = 0;
+#endif
 		buf_free(&outbuf);
 	}
 	buf_free(&buf);
@@ -3333,6 +3364,7 @@ static void usage(const char *progname)
 "    -o sshfs_sync          synchronous writes\n"
 "    -o no_readahead        synchronous reads (no speculative readahead)\n"
 "    -o sync_readdir        synchronous readdir\n"
+"    -o unreliable_append   Enable (unreliable) O_APPEND support\n"
 "    -d, --debug            print some debugging information (implies -f)\n"
 "    -o writeback_cache=BOOL enable writeback cache {yes,no} (default: yes)\n"
 "    -o dir_cache=BOOL      enable caching of directory contents (names,\n"
@@ -3820,9 +3852,6 @@ int main(int argc, char *argv[])
 	const char *sftp_server;
 	struct fuse *fuse;
 	struct fuse_session *se;
-#if !defined(__CYGWIN__)
-	struct stat st;
-#endif
 
 #ifdef __APPLE__
 	if (!realpath(*exec_path, sshfs_program_path)) {
@@ -3848,6 +3877,7 @@ int main(int argc, char *argv[])
 	sshfs.ptyfd = -1;
 	sshfs.dir_cache = 1;
 	sshfs.writeback_cache = 1;
+	sshfs.unrel_append = 0;
 	sshfs.show_help = 0;
 	sshfs.show_version = 0;
 	sshfs.singlethread = 0;
@@ -3895,7 +3925,7 @@ int main(int argc, char *argv[])
 		fprintf(stderr, "see `%s -h' for usage\n", argv[0]);
 		exit(1);
 	}
-	
+
 	if (sshfs.idmap == IDMAP_USER)
 		sshfs.detect_uid = 1;
 	else if (sshfs.idmap == IDMAP_FILE) {
@@ -3984,18 +4014,6 @@ int main(int argc, char *argv[])
 	g_free(tmp);
 	g_free(fsname);
 
-
-#if !defined(__CYGWIN__)
-	res = stat(sshfs.mountpoint, &st);
-	if (res == -1) {
-		perror(sshfs.mountpoint);
-		exit(1);
-	}
-	sshfs.mnt_mode = st.st_mode;
-#elif defined(__CYGWIN__)
-	sshfs.mnt_mode = S_IFDIR | 0755;
-#endif
-
 	if(sshfs.dir_cache)
 		sshfs.op = cache_wrap(&sshfs_oper);
 	else

test/meson.build

@@ -2,7 +2,7 @@ test_scripts = [ 'conftest.py', 'pytest.ini', 'test_sshfs.py',
                  'util.py' ]
 custom_target('test_scripts', input: test_scripts,
               output: test_scripts, build_by_default: true,
-              command: ['cp', '-fPu', '--preserve=mode',
+              command: ['cp', '-fP', '--preserve=mode',
                         '@INPUT@', meson.current_build_dir() ])
 
 # Provide something helpful when running 'ninja test'

test/test_sshfs.py

@@ -13,6 +13,7 @@ import stat
 import shutil
 import filecmp
 import errno
+from contextlib import contextmanager
 from tempfile import NamedTemporaryFile
 from util import (wait_for_mount, umount, cleanup, base_cmdline,
                   basename, fuse_test_marker, safe_sleep)
@@ -32,7 +33,9 @@ def name_generator(__ctr=[0]):
 @pytest.mark.parametrize("debug", (False, True))
 @pytest.mark.parametrize("cache_timeout", (0,1))
 @pytest.mark.parametrize("sync_rd", (True, False))
-def test_sshfs(tmpdir, debug, cache_timeout, sync_rd, capfd):
+@pytest.mark.parametrize("writeback", (False, True))
+def test_sshfs(tmpdir, debug, cache_timeout, sync_rd,
+               writeback, capfd):
     
     # Avoid false positives from debug messages
     #if debug:
@@ -61,7 +64,13 @@ def test_sshfs(tmpdir, debug, cache_timeout, sync_rd, capfd):
 
     if sync_rd:
         cmdline += [ '-o', 'sync_readdir' ]
-        
+
+    if writeback:
+        cmdline += [ '-o', 'writeback_cache=yes',
+                     '-o', 'unreliable_append' ]
+    else:
+        cmdline += [ '-o', 'writeback_cache=no' ]
+    
     # SSHFS Cache
     if cache_timeout == 0:
         cmdline += [ '-o', 'dir_cache=no' ]
@@ -87,6 +96,8 @@ def test_sshfs(tmpdir, debug, cache_timeout, sync_rd, capfd):
         tst_readdir(src_dir, mnt_dir)
         tst_open_read(src_dir, mnt_dir)
         tst_open_write(src_dir, mnt_dir)
+        tst_append(src_dir, mnt_dir)
+        tst_seek(src_dir, mnt_dir)
         tst_create(mnt_dir)
         tst_passthrough(src_dir, mnt_dir, cache_timeout)
         tst_mkdir(mnt_dir)
@@ -110,6 +121,17 @@ def test_sshfs(tmpdir, debug, cache_timeout, sync_rd, capfd):
     else:
         umount(mount_process, mnt_dir)
 
+@contextmanager
+def os_open(name, flags):
+    fd = os.open(name, flags)
+    try:
+        yield fd
+    finally:
+        os.close(fd)
+
+def os_create(name):
+    os.close(os.open(name, os.O_CREAT | os.O_RDWR))
+
 def tst_unlink(src_dir, mnt_dir, cache_timeout):
     name = name_generator()
     fullname = mnt_dir + "/" + name
@@ -215,6 +237,32 @@ def tst_open_write(src_dir, mnt_dir):
 
     assert filecmp.cmp(fullname, TEST_FILE, False)
 
+def tst_append(src_dir, mnt_dir):
+    name = name_generator()
+    os_create(pjoin(src_dir, name))
+    fullname = pjoin(mnt_dir, name)
+    with os_open(fullname, os.O_WRONLY) as fd:
+        os.write(fd, b'foo\n')
+    with os_open(fullname, os.O_WRONLY|os.O_APPEND) as fd:
+        os.write(fd, b'bar\n')
+
+    with open(fullname, 'rb') as fh:
+        assert fh.read() == b'foo\nbar\n'
+
+def tst_seek(src_dir, mnt_dir):
+    name = name_generator()
+    os_create(pjoin(src_dir, name))
+    fullname = pjoin(mnt_dir, name)
+    with os_open(fullname, os.O_WRONLY) as fd:
+        os.lseek(fd, 1, os.SEEK_SET)
+        os.write(fd, b'foobar\n')
+    with os_open(fullname, os.O_WRONLY) as fd:
+        os.lseek(fd, 4, os.SEEK_SET)
+        os.write(fd, b'com')
+
+    with open(fullname, 'rb') as fh:
+        assert fh.read() == b'\0foocom\n'
+
 def tst_open_unlink(mnt_dir):
     name = pjoin(mnt_dir, name_generator())
     data1 = b'foo'

test/travis-install.sh

@@ -14,16 +14,19 @@ ninja --version
 meson --version
 
 # Install fuse
-wget https://github.com/libfuse/libfuse/releases/download/fuse-3.0.2/fuse-3.0.2.tar.gz
-tar xzf fuse-3.0.2.tar.gz
-cd fuse-3.0.2
+wget https://github.com/libfuse/libfuse/archive/master.zip
+unzip master.zip
+cd libfuse-master
 mkdir build
 cd build
+export CC=gcc-6
 meson ..
 ninja
 sudo ninja install
 test -e /usr/local/lib/pkgconfig || sudo mkdir /usr/local/lib/pkgconfig
 sudo mv /usr/local/lib/*/pkgconfig/* /usr/local/lib/pkgconfig/
+ls -d1 /usr/local/lib/*-linux-gnu | sudo tee /etc/ld.so.conf.d/usrlocal.conf
+sudo ldconfig
 
 # Setup ssh
 ssh-keygen -b 768 -t rsa -f ~/.ssh/id_rsa -P ''