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101 lines
3.4 KiB
101 lines
3.4 KiB
package mount
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import (
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"github.com/hanwen/go-fuse/v2/fuse"
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)
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/**
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* Open a file
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*
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* Open flags are available in fi->flags. The following rules
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* apply.
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*
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* - Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be
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* filtered out / handled by the kernel.
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*
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* - Access modes (O_RDONLY, O_WRONLY, O_RDWR) should be used
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* by the filesystem to check if the operation is
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* permitted. If the ``-o default_permissions`` mount
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* option is given, this check is already done by the
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* kernel before calling open() and may thus be omitted by
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* the filesystem.
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*
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* - When writeback caching is enabled, the kernel may send
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* read requests even for files opened with O_WRONLY. The
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* filesystem should be prepared to handle this.
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*
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* - When writeback caching is disabled, the filesystem is
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* expected to properly handle the O_APPEND flag and ensure
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* that each write is appending to the end of the file.
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*
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* - When writeback caching is enabled, the kernel will
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* handle O_APPEND. However, unless all changes to the file
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* come through the kernel this will not work reliably. The
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* filesystem should thus either ignore the O_APPEND flag
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* (and let the kernel handle it), or return an error
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* (indicating that reliably O_APPEND is not available).
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*
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* Filesystem may store an arbitrary file handle (pointer,
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* index, etc) in fi->fh, and use this in other all other file
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* operations (read, write, flush, release, fsync).
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*
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* Filesystem may also implement stateless file I/O and not store
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* anything in fi->fh.
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*
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* There are also some flags (direct_io, keep_cache) which the
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* filesystem may set in fi, to change the way the file is opened.
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* See fuse_file_info structure in <fuse_common.h> for more details.
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*
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* If this request is answered with an error code of ENOSYS
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* and FUSE_CAP_NO_OPEN_SUPPORT is set in
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* `fuse_conn_info.capable`, this is treated as success and
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* future calls to open and release will also succeed without being
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* sent to the filesystem process.
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*
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* Valid replies:
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* fuse_reply_open
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* fuse_reply_err
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*
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* @param req request handle
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* @param ino the inode number
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* @param fi file information
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*/
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func (wfs *WFS) Open(cancel <-chan struct{}, in *fuse.OpenIn, out *fuse.OpenOut) (status fuse.Status) {
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var fileHandle *FileHandle
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fileHandle, status = wfs.AcquireHandle(in.NodeId, in.Flags, in.Uid, in.Gid)
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if status == fuse.OK {
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out.Fh = uint64(fileHandle.fh)
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out.OpenFlags = in.Flags
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// TODO https://github.com/libfuse/libfuse/blob/master/include/fuse_common.h#L64
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}
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return status
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}
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/**
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* Release an open file
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*
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* Release is called when there are no more references to an open
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* file: all file descriptors are closed and all memory mappings
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* are unmapped.
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*
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* For every open call there will be exactly one release call (unless
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* the filesystem is force-unmounted).
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*
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* The filesystem may reply with an error, but error values are
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* not returned to close() or munmap() which triggered the
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* release.
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*
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* fi->fh will contain the value set by the open method, or will
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* be undefined if the open method didn't set any value.
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* fi->flags will contain the same flags as for open.
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*
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* Valid replies:
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* fuse_reply_err
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*
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* @param req request handle
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* @param ino the inode number
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* @param fi file information
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*/
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func (wfs *WFS) Release(cancel <-chan struct{}, in *fuse.ReleaseIn) {
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wfs.ReleaseHandle(FileHandleId(in.Fh))
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}
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