head=254 is legal, and the check also assumes that heads=255, which is not
a given.  Remove the check and trust the LBA.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Partitions table entries with cyl=0 or head=0 are legal, avoid false
positives.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

open()'s prototype is traditionally open(const char*, int, ...) since
the third mode_t parameter is optional, and only needed if O_CREAT is
specified.

Change the definition to conform.

This allows the LFS64() macro to be used to define open64() with a
similar prototype.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

Make vget() accept a const char*, and adjust various other functions that
it calls in the same way.  This makes it easier to convert vfs_mount.c to
C++.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

We store the flags in a different format than fcntl() expects; perform the
needed conversions.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

The vfs converts the read/write flags from 0/1/2 (read-only/write-only/rw) to
bit fields which are more easily testable.  But in doing so it corrupts the
other flags.

Fix FFLAGS and OFLAGS to preserve those other flags.  The test for a file
that is not readable or writable is dropped, since it is impossible to fail.

Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

task_conv was wrongly converting "/.." and produced a path with unexpected
characters after /
Consequently, repeated calls (Java) to 'new File("/..").exists()' returned
ambigous results, not to mention other properties like isDirectory.

This confused the shell's completion mechanism (and me).

In more detail, in this (/..) situation 'len' was more than 2 (in line 105) which
caused 'tgt' to be pointing before the begining of 'full', from that point
whatever stopped the backward search for '/' (lines 109-112) was unexpected.
I guess this might occur with other combinations.

This sets 'len' to be 1 when starting an absolute path conversion, to match
the behavior where relative path conversion sets 'len = strlen(cwd)'.

Signed-off-by: Or Cohen <orc@fewbytes.com>

We can safely use the same function exit points for both successful and
error cases.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Call the dentry that refers to the newpath parent directory "newdirdp"
to make the code more explicit.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Filesystems are expected to wire up ->vop_link so it can never be NULL.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Make vn_stat() return inode number and link count in st_ino and
st_nlink, respectively.

Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

This patch adds the link() system call.

The system call uses the filesystem specific VOP_LINK vnode operation to
do the actual work.  ZFS is currently the only available file system
that supports hard links and the other filesystems return EPERM.

Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Wire up the VOP_LINK vnode operation for ramfs in preparation for
sys_link().

Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com>
[ penberg: split to separate commit ]
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Wire up the VOP_LINK vnode operation for devfs in preparation for
sys_link().

Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com>
[ penberg: split to separate commit ]
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Use ->rn_namelen as the destination buffer size for strlcpy().

Spotted by Coverity.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

The ramfs_remove_node() will free vp->v_data so we cannot look it up in
ramfs_remove().

Spotted by Coverity.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

Added Cloudius copyright statement to source files in fs/ which are our
own code (and not from Prex or FreeBSD). Also added our copyright statement
in addition to the original one when I thought we made non-trivial changes
to the original.

This code, living in device.c for maximum generality, will read the partition
table from any disk that calls it. Ideally, each new device would have its own
private data. But that would mean having to callback to the driver to set each
of the partitions up. Therefore, I found it easier to convention that all
partitions in the same drive have the same private data. This makes some sense
if we consider that the hypervisors are usually agnostic about partitions, and
all of the addressing and communications go through a single entry point, which
is the disk.

To support multiple partitions to a disk, I found it easier to add a
post-processing offset calculation to the bio just before calling the strategy.

The reason is, we have many (really many) entry points for bio preparation
(pre-strategy) and only two entry points for the strategy itself (the drivers).
Since multiplex_strategy is a good thing to be used even for virtio (although I
am not converting it now), since it allows for arbitrary sized requests, we
could very well reduce it to just one.

At this moment, the offset is always 0 and everything works as before.

I ended up forgetting to remove some kprintfs from device.c that were inserted
during Xen's blkfront development

Do to __xstat* what commit 018c672e
did to __fxstat* - they had the same problem.

In Linux, _STAT_VER is 1 on 64-bit (and 3 on 32-bit), but glibc never
verifies the argument to __fxstat64. JNR - a library used by JRuby -
wrongly (I believe) passes ver==0 to __fxstat64
(see jnr-posix/..../LinuxPosix.java). On Linux this wrong argument is
ignored but in our implementation, fails the check.

So this patch removes this check from our code as well, to let JNR and
therefore JRuby which uses it, use stat without failing.

Currently the umask is ignore (it's pointless since we have no users).

Needed by JRuby.

If dup3() is called with oldfd pointing to an existing file, it will close
the file for us.  37988879 converted fd operations to RCU, which caused
this close to be deferred until after the RCU grace period (43df74e7 fixed
this, but only for close(), not for dup3).

The asynchronous operation of dup3() should be fine, except that it triggers
a bug in sys_rename(): if the reference count of the vnode for either the
source or destination is elevated, rename fails with EBUSY.  This is due to
the coupling between vnodes and pathnames and can be fixed with the move
to separate dentries.

The whole sequence looks like

0xffffc000de90c010  3   1376912988.418660 vfs_lseek            95 0x0 0
0xffffc000de90c010  3   1376912988.418661 vfs_lseek_ret        0x0
0xffffc000de90c010  3   1376912988.418689 vfs_dup3             93 95 0x0
0xffffc000de90c010  3   1376912988.418696 vfs_dup3_ret         95
0xffffc000de90c010  3   1376912988.418711 vfs_close            95
0xffffc000de90c010  3   1376912988.418711 vfs_close_ret
...
0xffffc000de90c010  3   1376912988.420573 vfs_close            95
0xffffc000de90c010  3   1376912988.420580 vfs_close_ret
0xffffc000de90c010  3   1376912988.420738 vfs_rename           "/usr/var/lib/cassandra/data/system/local/system-local-tmp-ic-1-Index.db" "/usr/var/lib/cassandra/data/system/l
ocal/system-local-ic-1-Index.db"
0xffffc000de90c010  3   1376912988.422302 vfs_pwritev_ret      0x56
0xffffc000de90c010  3   1376912988.422302 vfs_rename_err       16

fd 95 (as it was before dup3) is still open at the time of the rename.

Fix by not deferring the fdrop() in fdset(); 43df74e7 already made fdrop()
safe to use directly.

Fixes failures with Cassandra.

v_path will go away once the vnode cache uses numeric indices for hardlink
support.

We'll need this for any pathname related actions.

Create a new dentry structure for pathname components, following the Linux
VFS model.  The vnodes are left-as is for now but are always fronted by
dentries for pathname lookups.  In a second step they will be moved to
use non-pathname indices.

[penberg: fix open(O_CREAT|O_EXCL) breakage ]

We'll pass the file to the open method soon, so make sure it's fully
constructed.

These aren't used in the build and will bitrot badly once
changing the VFS significantly.

This is used by subr_disk during bio flush operation

There are many other bio fields and functions that blkfront uses that are
not provided by our simplified bio. I am adding them here. One of the things we need is
a type definition of daddr_t. This already exists in fatfs.h, but it makes more sense to
live in the lower level code. So instead of including fatfs in bio.h, I am including
bio.h in fatfs and moving the daddr_t definition here.

Some block devices, such as the Xen blkfront, will have a maximum per-request size
that needs to be obeyed. In order for us to do it, we'll need to be aware of this
requirement in upper layers. So set up the device with it. We initialize the default
structure to make sure only interested parties need to set this up.

For xen, I would like to use an already existing device instead of creating one.
I still need to register it, though. I am here factoring out device_create in
a allocation and a registering part so I can use the later by itself.

Currently, we perform the final fdrop() in an rcu callback, which means it
can have considerable latency.  This in turn places restrictions on
further optimizations we can do to rcu, as we need prompt close() execution.

Relax this by performing the fdrop() immediately, and only deferring the
final free().  To do this, we harden fget() so it now expects files with
positive refcounts, and make sure that after the final fdrop() refcounts
are either zero or negative.

This also makes close() take effect immediately, which fixes tst-pipe.so.

This patch changes fget() to no longer take gfdt_lock, using rcu instead.