This call copies a file descriptor from a remote process into the
calling process. The call is for the VND driver only, and in the
future, ACLs will prevent any other process from using this call.
Change-Id: Ib16fdd1f1a12cb38a70d7e441dad91bc86898f6d
Because pipes have no file position. VFS maintained (file) offsets into a
buffer internal to PFS and stored them in vnodes for simplicity, mixing
the responsibilities of filp and vnode objects.
With this patch PFS ignores the position field in REQ_READ and REQ_WRITE
requests making VFS' job a lot simpler.
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
- Several path lookup bugs in MFS.
- A link can be too big for the path buffer.
- A mountpoint can become inaccessible when the creation of a new inode
fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
named pipes. However, named pipes still reside on the (M)FS, as they are part
of the file system on disk. To make this work VFS now has a concept of
'mapped' inodes, which causes read, write, truncate and stat requests to be
redirected to the mapped FS, and all other requests to the original FS.
if the process was REVIVING. (susp_count doesn't count those
processes.) this together with dev_io SELECT suspend side effect
for asynch. character devices solves the hanging pipe bug. or
at last vastly improves it.
added sanity checks, turned off by default.
made the {NOT_,}{SUSPENDING,REVIVING} constants weirder to
help sanity checking.
