diff options
| -rw-r--r-- | ChangeLog.rst | 10 | ||||
| -rw-r--r-- | sshfs.c | 6 | ||||
| -rw-r--r-- | sshfs.rst | 11 |
3 files changed, 27 insertions, 0 deletions
diff --git a/ChangeLog.rst b/ChangeLog.rst index 3f3d796..16d75f7 100644 --- a/ChangeLog.rst +++ b/ChangeLog.rst @@ -1,3 +1,13 @@ +Unreleased Changes +------------------ + +* Added "-o direct_io" option. + This option disables the use of page cache in kernel. + This is useful for example if the file size is not known before reading it. + For example if you mount /proc dir from a remote host without the direct_io + option, the read always will return zero bytes instead of actual data. + + Release 3.5.2 (2019-04-13) -------------------------- @@ -244,6 +244,7 @@ struct sshfs { int sync_write; int sync_read; int sync_readdir; + int direct_io; int debug; int verbose; int foreground; @@ -410,6 +411,7 @@ static struct fuse_opt sshfs_opts[] = { SSHFS_OPT("disable_hardlink", disable_hardlink, 1), SSHFS_OPT("dir_cache=yes", dir_cache, 1), SSHFS_OPT("dir_cache=no", dir_cache, 0), + SSHFS_OPT("direct_io", direct_io, 1), SSHFS_OPT("-h", show_help, 1), SSHFS_OPT("--help", show_help, 1), @@ -2516,6 +2518,9 @@ static int sshfs_open_common(const char *path, mode_t mode, if (sshfs.dir_cache) wrctr = cache_get_write_ctr(); + if (sshfs.direct_io) + fi->direct_io = 1; + if ((fi->flags & O_ACCMODE) == O_RDONLY) pflags = SSH_FXF_READ; else if((fi->flags & O_ACCMODE) == O_WRONLY) @@ -3377,6 +3382,7 @@ static void usage(const char *progname) " -o dcache_min_clean_interval=N\n" " sets the interval for forced cleaning of the\n" " cache if full (default: 5)\n" +" -o direct_io enable direct i/o\n" " -o workaround=LIST colon separated list of workarounds\n" " none no workarounds enabled\n" " [no]rename fix renaming to existing file (default: off)\n" @@ -202,6 +202,17 @@ Options sets the interval for forced cleaning of the directory cache when full. +-o direct_io + This option disables the use of page cache (file content cache) in + the kernel for this filesystem. + This has several affects: + 1. Each read() or write() system call will initiate one or more read or + write operations, data will not be cached in the kernel. + 2. The return value of the read() and write() system calls will correspond + to the return values of the read and write operations. This is useful + for example if the file size is not known in advance (before reading it). + e.g. /proc filesystem + In addition, SSHFS accepts several options common to all FUSE file systems. These are described in the `mount.fuse` manpage (look for "general", "libfuse specific", and "high-level API" options). |