Merge pull request #1321 from trapexit/allowmmap

Add support for 'direct-io-allow-mmap' if supported by kernel

README.md

@@ -91,6 +91,11 @@ start with one of the following option sets.
 
 `cache.files=auto-full,dropcacheonclose=true,category.create=mfs`
 
+or if you are on a Linux kernel >= 6.6.x mergerfs will enable a mode
+that allows shared mmap when `cache.files=off`. To be sure of the best
+performance between `cache.files=off` and `cache.files=auto-full`
+you'll need to do your own benchmarking but often `off` is faster.
+
 #### You don't need `mmap`
 
 `cache.files=off,dropcacheonclose=true,category.create=mfs`
@@ -162,6 +167,11 @@ These options are the same regardless of whether you use them with the
   longer need the data and it can drop its cache. Recommended when
   **cache.files=partial|full|auto-full|per-process** to limit double
   caching. (default: false)
+* **direct-io-allow-mmap=BOOL**: On newer kernels (>= 6.6) it is
+  possible to disable file page caching while still allowing for
+  shared mmap support. mergerfs will enable this feature if available
+  but an option is provided to turn it off for testing and debugging
+  purposes. (default: true)
 * **symlinkify=BOOL**: When enabled and a file is not writable and its
   mtime or ctime is older than **symlinkify_timeout** files will be
   reported as symlinks to the original files. Please read more below

libfuse/include/fuse_common.h

@@ -108,23 +108,26 @@ struct fuse_file_info_t
  * FUSE_CAP_IOCTL_DIR: ioctl support on directories
  * FUSE_CAP_CACHE_SYMLINKS: cache READLINK responses
  */
-#define FUSE_CAP_ASYNC_READ        (1 << 0)
-#define FUSE_CAP_POSIX_LOCKS       (1 << 1)
-#define FUSE_CAP_ATOMIC_O_TRUNC    (1 << 3)
-#define FUSE_CAP_EXPORT_SUPPORT    (1 << 4)
-#define FUSE_CAP_BIG_WRITES        (1 << 5)
-#define FUSE_CAP_DONT_MASK         (1 << 6)
-#define FUSE_CAP_FLOCK_LOCKS       (1 << 10)
-#define FUSE_CAP_IOCTL_DIR         (1 << 11)
-#define FUSE_CAP_READDIR_PLUS      (1 << 13)
-#define FUSE_CAP_READDIR_PLUS_AUTO (1 << 14)
-#define FUSE_CAP_ASYNC_DIO         (1 << 15)
-#define FUSE_CAP_WRITEBACK_CACHE   (1 << 16)
-#define FUSE_CAP_PARALLEL_DIROPS   (1 << 18)
-#define FUSE_CAP_POSIX_ACL         (1 << 19)
-#define FUSE_CAP_CACHE_SYMLINKS    (1 << 20)
-#define FUSE_CAP_MAX_PAGES         (1 << 21)
-#define FUSE_CAP_SETXATTR_EXT      (1 << 22)
+#define FUSE_CAP_ASYNC_READ           (1ULL << 0)
+#define FUSE_CAP_POSIX_LOCKS          (1ULL << 1)
+#define FUSE_CAP_ATOMIC_O_TRUNC       (1ULL << 3)
+#define FUSE_CAP_EXPORT_SUPPORT       (1ULL << 4)
+#define FUSE_CAP_BIG_WRITES           (1ULL << 5)
+#define FUSE_CAP_DONT_MASK            (1ULL << 6)
+#define FUSE_CAP_FLOCK_LOCKS          (1ULL << 10)
+#define FUSE_CAP_IOCTL_DIR            (1ULL << 11)
+#define FUSE_CAP_READDIR_PLUS         (1ULL << 13)
+#define FUSE_CAP_READDIR_PLUS_AUTO    (1ULL << 14)
+#define FUSE_CAP_ASYNC_DIO            (1ULL << 15)
+#define FUSE_CAP_WRITEBACK_CACHE      (1ULL << 16)
+#define FUSE_CAP_PARALLEL_DIROPS      (1ULL << 18)
+#define FUSE_CAP_POSIX_ACL            (1ULL << 19)
+#define FUSE_CAP_CACHE_SYMLINKS       (1ULL << 20)
+#define FUSE_CAP_MAX_PAGES            (1ULL << 21)
+#define FUSE_CAP_SETXATTR_EXT         (1ULL << 22)
+#define FUSE_CAP_DIRECT_IO_ALLOW_MMAP (1ULL << 23)
+#define FUSE_CAP_CREATE_SUPP_GROUP    (1ULL << 24)
+
 
 /**
  * Ioctl flags
@@ -150,56 +153,17 @@ struct fuse_file_info_t
  * indicate the value requested by the filesystem.  The requested
  * value must usually be smaller than the indicated value.
  */
-struct fuse_conn_info {
-  /**
-   * Major version of the protocol (read-only)
-   */
+struct fuse_conn_info
+{
   unsigned proto_major;
-
-  /**
-   * Minor version of the protocol (read-only)
-   */
   unsigned proto_minor;
-
-  /**
-   * Maximum size of the write buffer
-   */
   unsigned max_write;
-
-  /**
-   * Maximum readahead
-   */
   unsigned max_readahead;
-
-  /**
-   * Capability flags, that the kernel supports
-   */
-  unsigned capable;
-
-  /**
-   * Capability flags, that the filesystem wants to enable
-   */
-  unsigned want;
-
-  /**
-   * Maximum number of backgrounded requests
-   */
+  uint64_t capable;
+  uint64_t want;
   unsigned max_background;
-
-  /**
-   * Kernel congestion threshold parameter
-   */
   unsigned congestion_threshold;
-
-  /**
-   * Max pages
-   */
   uint16_t max_pages;
-
-  /**
-   * For future use.
-   */
-  unsigned reserved[22];
 };
 
 struct fuse_session;

libfuse/lib/debug.c

@@ -158,9 +158,9 @@ open_flag_to_str(const uint64_t offset_)
 static
 const
 char*
-fuse_flag_to_str(const uint32_t offset_)
+fuse_flag_to_str(const uint64_t offset_)
 {
-  switch(1 << offset_)
+  switch(1ULL << offset_)
     {
       FUSE_INIT_FLAG_CASE(ASYNC_READ);
       FUSE_INIT_FLAG_CASE(POSIX_LOCKS);
@@ -189,6 +189,16 @@ fuse_flag_to_str(const uint32_t offset_)
       FUSE_INIT_FLAG_CASE(NO_OPENDIR_SUPPORT);
       FUSE_INIT_FLAG_CASE(EXPLICIT_INVAL_DATA);
       FUSE_INIT_FLAG_CASE(MAP_ALIGNMENT);
+      FUSE_INIT_FLAG_CASE(SUBMOUNTS);
+      FUSE_INIT_FLAG_CASE(HANDLE_KILLPRIV_V2);
+      FUSE_INIT_FLAG_CASE(SETXATTR_EXT);
+      FUSE_INIT_FLAG_CASE(INIT_EXT);
+      FUSE_INIT_FLAG_CASE(INIT_RESERVED);
+      FUSE_INIT_FLAG_CASE(SECURITY_CTX);
+      FUSE_INIT_FLAG_CASE(HAS_INODE_DAX);
+      FUSE_INIT_FLAG_CASE(CREATE_SUPP_GROUP);
+      FUSE_INIT_FLAG_CASE(HAS_EXPIRE_ONLY);
+      FUSE_INIT_FLAG_CASE(DIRECT_IO_ALLOW_MMAP);
     }
 
   return NULL;
@@ -717,21 +727,24 @@ debug_fuse_fallocate_in(const void *arg_)
 void
 debug_fuse_init_in(const struct fuse_init_in *arg_)
 {
+  uint64_t flags;
+
+  flags = (((uint64_t)arg_->flags) | ((uint64_t)arg_->flags2) << 32);
   fprintf(g_OUTPUT,
           "FUSE_INIT_IN: "
           " major=%u;"
           " minor=%u;"
           " max_readahead=%u;"
-          " flags=0x%08X (",
+          " flags=0x%016lx (",
           arg_->major,
           arg_->minor,
           arg_->max_readahead,
-          arg_->flags);
-  for(uint64_t i = 0; i < (sizeof(arg_->flags)*8); i++)
+          flags);
+  for(uint64_t i = 0; i < (sizeof(flags)*8); i++)
     {
       const char *str;
 
-      if(!(arg_->flags & (1ULL << i)))
+      if(!(flags & (1ULL << i)))
         continue;
 
       str = fuse_flag_to_str(i);
@@ -748,7 +761,10 @@ debug_fuse_init_out(const uint64_t              unique_,
                     const struct fuse_init_out *arg_,
                     const uint64_t              argsize_)
 {
+  uint64_t flags;
   const struct fuse_init_out *arg = arg_;
+
+  flags = (((uint64_t)arg->flags) | ((uint64_t)arg->flags2) << 32);
   fprintf(g_OUTPUT,
           /* "unique=0x%016"PRIx64";" */
           /* " opcode=RESPONSE;" */
@@ -758,20 +774,20 @@ debug_fuse_init_out(const uint64_t              unique_,
           " major=%u;"
           " minor=%u;"
           " max_readahead=%u;"
-          " flags=0x%08X ("
+          " flags=0x%016lx ("
           ,
           /* unique_, */
           /* sizeof(struct fuse_out_header) + argsize_, */
           arg->major,
           arg->minor,
           arg->max_readahead,
-          arg->flags);
+          flags);
 
-  for(uint64_t i = 0; i < (sizeof(arg->flags)*8); i++)
+  for(uint64_t i = 0; i < (sizeof(flags)*8); i++)
     {
       const char *str;
 
-      if(!(arg->flags & (1ULL << i)))
+      if(!(flags & (1ULL << i)))
         continue;
 
       str = fuse_flag_to_str(i);

libfuse/lib/fuse_lowlevel.c

@@ -1097,6 +1097,11 @@ do_init(fuse_req_t             req,
   struct fuse_init_in *arg = (struct fuse_init_in *) &hdr_[1];
   struct fuse_ll *f = req->f;
   size_t bufsize = fuse_chan_bufsize(req->ch);
+  uint64_t inargflags;
+  uint64_t outargflags;
+
+  inargflags = 0;
+  outargflags = 0;
 
   if(f->debug)
     debug_fuse_init_in(arg);
@@ -1127,40 +1132,49 @@ do_init(fuse_req_t             req,
 
   if(arg->minor >= 6)
     {
+      inargflags = arg->flags;
+      if(inargflags & FUSE_INIT_EXT)
+        inargflags |= (((uint64_t)arg->flags2) << 32);
+
       if(arg->max_readahead < f->conn.max_readahead)
         f->conn.max_readahead = arg->max_readahead;
-      if(arg->flags & FUSE_ASYNC_READ)
+
+      if(inargflags & FUSE_ASYNC_READ)
         f->conn.capable |= FUSE_CAP_ASYNC_READ;
-      if(arg->flags & FUSE_POSIX_LOCKS)
+      if(inargflags & FUSE_POSIX_LOCKS)
         f->conn.capable |= FUSE_CAP_POSIX_LOCKS;
-      if(arg->flags & FUSE_ATOMIC_O_TRUNC)
+      if(inargflags & FUSE_ATOMIC_O_TRUNC)
         f->conn.capable |= FUSE_CAP_ATOMIC_O_TRUNC;
-      if(arg->flags & FUSE_EXPORT_SUPPORT)
+      if(inargflags & FUSE_EXPORT_SUPPORT)
         f->conn.capable |= FUSE_CAP_EXPORT_SUPPORT;
-      if(arg->flags & FUSE_BIG_WRITES)
+      if(inargflags & FUSE_BIG_WRITES)
         f->conn.capable |= FUSE_CAP_BIG_WRITES;
-      if(arg->flags & FUSE_DONT_MASK)
+      if(inargflags & FUSE_DONT_MASK)
         f->conn.capable |= FUSE_CAP_DONT_MASK;
-      if(arg->flags & FUSE_FLOCK_LOCKS)
+      if(inargflags & FUSE_FLOCK_LOCKS)
         f->conn.capable |= FUSE_CAP_FLOCK_LOCKS;
-      if(arg->flags & FUSE_POSIX_ACL)
+      if(inargflags & FUSE_POSIX_ACL)
         f->conn.capable |= FUSE_CAP_POSIX_ACL;
-      if(arg->flags & FUSE_CACHE_SYMLINKS)
+      if(inargflags & FUSE_CACHE_SYMLINKS)
         f->conn.capable |= FUSE_CAP_CACHE_SYMLINKS;
-      if(arg->flags & FUSE_ASYNC_DIO)
+      if(inargflags & FUSE_ASYNC_DIO)
         f->conn.capable |= FUSE_CAP_ASYNC_DIO;
-      if(arg->flags & FUSE_PARALLEL_DIROPS)
+      if(inargflags & FUSE_PARALLEL_DIROPS)
         f->conn.capable |= FUSE_CAP_PARALLEL_DIROPS;
-      if(arg->flags & FUSE_MAX_PAGES)
+      if(inargflags & FUSE_MAX_PAGES)
         f->conn.capable |= FUSE_CAP_MAX_PAGES;
-      if(arg->flags & FUSE_WRITEBACK_CACHE)
+      if(inargflags & FUSE_WRITEBACK_CACHE)
         f->conn.capable |= FUSE_CAP_WRITEBACK_CACHE;
-      if(arg->flags & FUSE_DO_READDIRPLUS)
+      if(inargflags & FUSE_DO_READDIRPLUS)
         f->conn.capable |= FUSE_CAP_READDIR_PLUS;
-      if(arg->flags & FUSE_READDIRPLUS_AUTO)
+      if(inargflags & FUSE_READDIRPLUS_AUTO)
         f->conn.capable |= FUSE_CAP_READDIR_PLUS_AUTO;
-      if(arg->flags & FUSE_SETXATTR_EXT)
+      if(inargflags & FUSE_SETXATTR_EXT)
         f->conn.capable |= FUSE_CAP_SETXATTR_EXT;
+      if(inargflags & FUSE_DIRECT_IO_ALLOW_MMAP)
+        f->conn.capable |= FUSE_CAP_DIRECT_IO_ALLOW_MMAP;
+      if(inargflags & FUSE_CREATE_SUPP_GROUP)
+        f->conn.capable |= FUSE_CAP_CREATE_SUPP_GROUP;
     }
   else
     {
@@ -1191,44 +1205,57 @@ do_init(fuse_req_t             req,
   if(f->op.init)
     f->op.init(f->userdata, &f->conn);
 
-  if((arg->flags & FUSE_MAX_PAGES) && (f->conn.want & FUSE_CAP_MAX_PAGES))
+  outargflags = outarg.flags;
+  if((inargflags & FUSE_MAX_PAGES) && (f->conn.want & FUSE_CAP_MAX_PAGES))
     {
-      outarg.flags     |= FUSE_MAX_PAGES;
+      outargflags     |= FUSE_MAX_PAGES;
       outarg.max_pages  = f->conn.max_pages;
 
       msgbuf_set_bufsize(outarg.max_pages + 1);
     }
 
   if(f->conn.want & FUSE_CAP_ASYNC_READ)
-    outarg.flags |= FUSE_ASYNC_READ;
+    outargflags |= FUSE_ASYNC_READ;
   if(f->conn.want & FUSE_CAP_POSIX_LOCKS)
-    outarg.flags |= FUSE_POSIX_LOCKS;
+    outargflags |= FUSE_POSIX_LOCKS;
   if(f->conn.want & FUSE_CAP_ATOMIC_O_TRUNC)
-    outarg.flags |= FUSE_ATOMIC_O_TRUNC;
+    outargflags |= FUSE_ATOMIC_O_TRUNC;
   if(f->conn.want & FUSE_CAP_EXPORT_SUPPORT)
-    outarg.flags |= FUSE_EXPORT_SUPPORT;
+    outargflags |= FUSE_EXPORT_SUPPORT;
   if(f->conn.want & FUSE_CAP_BIG_WRITES)
-    outarg.flags |= FUSE_BIG_WRITES;
+    outargflags |= FUSE_BIG_WRITES;
   if(f->conn.want & FUSE_CAP_DONT_MASK)
-    outarg.flags |= FUSE_DONT_MASK;
+    outargflags |= FUSE_DONT_MASK;
   if(f->conn.want & FUSE_CAP_FLOCK_LOCKS)
-    outarg.flags |= FUSE_FLOCK_LOCKS;
+    outargflags |= FUSE_FLOCK_LOCKS;
   if(f->conn.want & FUSE_CAP_POSIX_ACL)
-    outarg.flags |= FUSE_POSIX_ACL;
+    outargflags |= FUSE_POSIX_ACL;
   if(f->conn.want & FUSE_CAP_CACHE_SYMLINKS)
-    outarg.flags |= FUSE_CACHE_SYMLINKS;
+    outargflags |= FUSE_CACHE_SYMLINKS;
   if(f->conn.want & FUSE_CAP_ASYNC_DIO)
-    outarg.flags |= FUSE_ASYNC_DIO;
+    outargflags |= FUSE_ASYNC_DIO;
   if(f->conn.want & FUSE_CAP_PARALLEL_DIROPS)
-    outarg.flags |= FUSE_PARALLEL_DIROPS;
+    outargflags |= FUSE_PARALLEL_DIROPS;
   if(f->conn.want & FUSE_CAP_WRITEBACK_CACHE)
-    outarg.flags |= FUSE_WRITEBACK_CACHE;
+    outargflags |= FUSE_WRITEBACK_CACHE;
   if(f->conn.want & FUSE_CAP_READDIR_PLUS)
-    outarg.flags |= FUSE_DO_READDIRPLUS;
+    outargflags |= FUSE_DO_READDIRPLUS;
   if(f->conn.want & FUSE_CAP_READDIR_PLUS_AUTO)
-    outarg.flags |= FUSE_READDIRPLUS_AUTO;
+    outargflags |= FUSE_READDIRPLUS_AUTO;
   if(f->conn.want & FUSE_CAP_SETXATTR_EXT)
-    outarg.flags |= FUSE_SETXATTR_EXT;
+    outargflags |= FUSE_SETXATTR_EXT;
+  if(f->conn.want & FUSE_CAP_CREATE_SUPP_GROUP)
+    outargflags |= FUSE_CREATE_SUPP_GROUP;
+  if(f->conn.want & FUSE_CAP_DIRECT_IO_ALLOW_MMAP)
+    outargflags |= FUSE_DIRECT_IO_ALLOW_MMAP;
+
+  if(inargflags & FUSE_INIT_EXT)
+    {
+      outargflags |= FUSE_INIT_EXT;
+      outarg.flags2 = (outargflags >> 32);
+    }
+
+  outarg.flags = outargflags;
 
   outarg.max_readahead = f->conn.max_readahead;
   outarg.max_write = f->conn.max_write;
@@ -1247,6 +1274,9 @@ do_init(fuse_req_t             req,
       outarg.congestion_threshold = f->conn.congestion_threshold;
     }
 
+  if(f->conn.proto_minor >= 23)
+    outarg.time_gran = 1;
+
   size_t outargsize;
   if(arg->minor < 5)
     outargsize = FUSE_COMPAT_INIT_OUT_SIZE;

man/mergerfs.1

@@ -106,16 +106,22 @@ If you don\[cq]t already know that you have a special use case then just
 start with one of the following option sets.
 .SS You need \f[C]mmap\f[R] (used by rtorrent and many sqlite3 base software)
 .PP
-\f[C]cache.files=partial,dropcacheonclose=true,category.create=mfs\f[R]
+\f[C]cache.files=auto-full,dropcacheonclose=true,category.create=mfs\f[R]
+.PP
+or if you are on a Linux kernel >= 6.6.x mergerfs will enable a mode
+that allows shared mmap when \f[C]cache.files=off\f[R].
+To be sure of the best performance between \f[C]cache.files=off\f[R] and
+\f[C]cache.files=auto-full\f[R] you\[cq]ll need to do your own
+benchmarking but often \f[C]off\f[R] is faster.
 .SS You don\[cq]t need \f[C]mmap\f[R]
 .PP
 \f[C]cache.files=off,dropcacheonclose=true,category.create=mfs\f[R]
 .SS Command Line
 .PP
-\f[C]mergerfs -o cache.files=partial,dropcacheonclose=true,category.create=mfs /mnt/hdd0:/mnt/hdd1 /media\f[R]
+\f[C]mergerfs -o cache.files=auto-full,dropcacheonclose=true,category.create=mfs /mnt/hdd0:/mnt/hdd1 /media\f[R]
 .SS /etc/fstab
 .PP
-\f[C]/mnt/hdd0:/mnt/hdd1 /media mergerfs cache.files=partial,dropcacheonclose=true,category.create=mfs 0 0\f[R]
+\f[C]/mnt/hdd0:/mnt/hdd1 /media mergerfs cache.files=auto-full,dropcacheonclose=true,category.create=mfs 0 0\f[R]
 .SS systemd mount
 .PP
 https://github.com/trapexit/mergerfs/wiki/systemd
@@ -130,7 +136,7 @@ Type=simple
 KillMode=none
 ExecStart=/usr/bin/mergerfs \[rs]
   -f \[rs]
-  -o cache.files=partial \[rs]
+  -o cache.files=auto-full \[rs]
   -o dropcacheonclose=true \[rs]
   -o category.create=mfs \[rs]
   /mnt/hdd0:/mnt/hdd1 \[rs]
@@ -185,6 +191,13 @@ Recommended when
 caching.
 (default: false)
 .IP \[bu] 2
+\f[B]direct-io-allow-mmap=BOOL\f[R]: On newer kernels (>= 6.6) it is
+possible to disable file page caching while still allowing for shared
+mmap support.
+mergerfs will enable this feature if available but an option is provided
+to turn it off for testing and debugging purposes.
+(default: true)
+.IP \[bu] 2
 \f[B]symlinkify=BOOL\f[R]: When enabled and a file is not writable and
 its mtime or ctime is older than \f[B]symlinkify_timeout\f[R] files will
 be reported as symlinks to the original files.
@@ -2396,8 +2409,8 @@ Take a look at the section on NFS in the #remote-filesystems for more
 details.
 .SS rtorrent fails with ENODEV (No such device)
 .PP
-Be sure to set \f[C]cache.files=partial|full|auto-full|per-processe\f[R]
-or turn off \f[C]direct_io\f[R].
+Be sure to set
+\f[C]cache.files=partial|full|auto-full|per-processe\f[R].
 rtorrent and some other applications use
 mmap (http://linux.die.net/man/2/mmap) to read and write to files and
 offer no fallback to traditional methods.

src/config.cpp

@@ -58,6 +58,7 @@ namespace l
     IFERT("branches-mount-timeout");
     IFERT("cache.symlinks");
     IFERT("cache.writeback");
+    IFERT("direct-io-allow-mmap");
     IFERT("export-support");
     IFERT("fsname");
     IFERT("fuse_msg_size");
@@ -94,6 +95,7 @@ Config::Config()
     cache_symlinks(false),
     category(func),
     direct_io(false),
+    direct_io_allow_mmap(true),
     dropcacheonclose(false),
     export_support(true),
     flushonclose(FlushOnClose::ENUM::OPENED_FOR_WRITE),
@@ -150,6 +152,7 @@ Config::Config()
   _map["category.create"]        = &category.create;
   _map["category.search"]        = &category.search;
   _map["direct_io"]              = &direct_io;
+  _map["direct-io-allow-mmap"]   = &direct_io_allow_mmap;
   _map["dropcacheonclose"]       = &dropcacheonclose;
   _map["export-support"]         = &export_support;
   _map["flush-on-close"]         = &flushonclose;

src/config.hpp

@@ -117,6 +117,7 @@ public:
   ConfigBOOL     cache_symlinks;
   Categories     category;
   ConfigBOOL     direct_io;
+  ConfigBOOL     direct_io_allow_mmap;
   ConfigBOOL     dropcacheonclose;
   ConfigBOOL     export_support;
   FlushOnClose   flushonclose;

src/fuse_init.cpp

@@ -144,14 +144,15 @@ namespace FUSE
     l::want_if_capable(conn_,FUSE_CAP_ATOMIC_O_TRUNC);
     l::want_if_capable(conn_,FUSE_CAP_BIG_WRITES);
     l::want_if_capable(conn_,FUSE_CAP_CACHE_SYMLINKS,&cfg->cache_symlinks);
+    l::want_if_capable(conn_,FUSE_CAP_DIRECT_IO_ALLOW_MMAP,&cfg->direct_io_allow_mmap);
     l::want_if_capable(conn_,FUSE_CAP_DONT_MASK);
     l::want_if_capable(conn_,FUSE_CAP_EXPORT_SUPPORT,&cfg->export_support);
     l::want_if_capable(conn_,FUSE_CAP_IOCTL_DIR);
     l::want_if_capable(conn_,FUSE_CAP_PARALLEL_DIROPS);
     l::want_if_capable(conn_,FUSE_CAP_POSIX_ACL,&cfg->posix_acl);
     l::want_if_capable(conn_,FUSE_CAP_READDIR_PLUS,&cfg->readdirplus);
-    //    l::want_if_capable(conn_,FUSE_CAP_READDIR_PLUS_AUTO);
     l::want_if_capable(conn_,FUSE_CAP_WRITEBACK_CACHE,&cfg->writeback_cache);
+    //    l::want_if_capable(conn_,FUSE_CAP_READDIR_PLUS_AUTO);
     l::want_if_capable_max_pages(conn_,cfg);
     conn_->want &= ~FUSE_CAP_POSIX_LOCKS;
     conn_->want &= ~FUSE_CAP_FLOCK_LOCKS;