Commit Graph

20 Commits

Author SHA1 Message Date
Miklos Szeredi
9cd6845511 [PATCH] fuse: fix async read for legacy filesystems
While asynchronous reads mean a performance improvement in most cases, if
the filesystem assumed that reads are synchronous, then async reads may
degrade performance (filesystem may receive reads out of order, which can
confuse it's own readahead logic).

With sshfs a 1.5 to 4 times slowdown can be measured.

There's also a need for userspace filesystems to know whether asynchronous
reads are supported by the kernel or not.

To achive these, negotiate in the INIT request whether async reads will be
used and the maximum readahead value.  Update interface version to 7.6

If userspace uses a version earlier than 7.6, then disable async reads, and
set maximum readahead value to the maximum read size, as done in previous
versions.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:09 -08:00
Miklos Szeredi
3ec870d524 [PATCH] fuse: make maximum write data configurable
Make the maximum size of write data configurable by the filesystem.  The
previous fixed 4096 limit only worked on architectures where the page size is
less or equal to this.  This change make writing work on other architectures
too, and also lets the filesystem receive bigger write requests in direct_io
mode.

Normal writes which go through the page cache are still limited to a page
sized chunk per request.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:56 -08:00
Miklos Szeredi
1d3d752b47 [PATCH] fuse: clean up request size limit checking
Change the way a too large request is handled.  Until now in this case the
device read returned -EINVAL and the operation returned -EIO.

Make it more flexibible by not returning -EINVAL from the read, but restarting
it instead.

Also remove the fixed limit on setxattr data and let the filesystem provide as
large a read buffer as it needs to handle the extended attribute data.

The symbolic link length is already checked by VFS to be less than PATH_MAX,
so the extra check against FUSE_SYMLINK_MAX is not needed.

The check in fuse_create_open() against FUSE_NAME_MAX is not needed, since the
dentry has already been looked up, and hence the name already checked.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:56 -08:00
Miklos Szeredi
de5f120255 [PATCH] fuse: add frsize to statfs reply
Add 'frsize' member to the statfs reply.

I'm not sure if sending f_fsid will ever be needed, but just in case leave
some space at the end of the structure, so less compatibility mess would be
required.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:55 -08:00
Miklos Szeredi
45714d6561 [PATCH] fuse: bump interface version
Change interface version to 7.4.

Following changes will need backward compatibility support, so store the minor
version returned by userspace.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:55 -08:00
Miklos Szeredi
befc649c22 [PATCH] FUSE: pass file handle in setattr
This patch passes the file handle supplied in iattr to userspace, in case the
->setattr() was invoked from sys_ftruncate().  This solves the permission
checking (or lack thereof) in ftruncate() for the class of filesystems served
by an unprivileged userspace process.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:42 -08:00
Miklos Szeredi
fd72faac95 [PATCH] FUSE: atomic create+open
This patch adds an atomic create+open operation.  This does not yet work if
the file type changes between lookup and create+open, but solves the
permission checking problems for the separte create and open methods.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:42 -08:00
Miklos Szeredi
31d40d74b4 [PATCH] FUSE: add access call
Add a new access call, which will only be called if ->permission is invoked
from sys_access().  In all other cases permission checking is delayed until
the actual filesystem operation.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:42 -08:00
Miklos Szeredi
5b62073d50 [PATCH] FUSE: bump interface minor version
Though the following changes are all backward compatible (from the kernel's as
well as the library's POV) change the minor version, so interested
applications can detect new features.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:42 -08:00
Miklos Szeredi
6ea05db06f [PATCH] fuse: remove unused define
Setting ctime is implicit in all setattr cases, so the FATTR_CTIME
definition is unnecessary.

It is used by neither the kernel nor by userspace.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:24 -08:00
Miklos Szeredi
8254798199 [PATCH] FUSE: add fsync operation for directories
This patch adds a new FSYNCDIR request, which is sent when fsync is called
on directories.  This operation is available in libfuse 2.3-pre1 or
greater.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:47 -07:00
Miklos Szeredi
45323fb764 [PATCH] fuse: more flexible caching
Make data caching behavior selectable on a per-open basis instead of
per-mount.  Compatibility for the old mount options 'kernel_cache' and
'direct_io' is retained in the userspace library (version 2.4.0-pre1 or
later).

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:47 -07:00
Miklos Szeredi
04730fef1f [PATCH] fuse: transfer readdir data through device
This patch removes a long lasting "hack" in FUSE, which used a separate
channel (a file descriptor refering to a disk-file) to transfer directory
contents from userspace to the kernel.

The patch adds three new operations (OPENDIR, READDIR, RELEASEDIR), which
have semantics and implementation exactly maching the respective file
operations (OPEN, READ, RELEASE).

This simplifies the directory reading code.  Also disk space is not
necessary, which can be important in embedded systems.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:47 -07:00
Miklos Szeredi
06663267b4 [PATCH] FUSE: add padding
Add padding to structures to make sizes the same on 32bit and 64bit archs.
Initial testing and test machine generously provided by Franco Broi.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:46 -07:00
Miklos Szeredi
92a8780e11 [PATCH] FUSE - extended attribute operations
This patch adds the extended attribute operations to FUSE.

The following operations are added:

 o getxattr
 o setxattr
 o listxattr
 o removexattr

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:45 -07:00
Miklos Szeredi
b6aeadeda2 [PATCH] FUSE - file operations
This patch adds the file operations of FUSE.

The following operations are added:

 o open
 o flush
 o release
 o fsync
 o readpage
 o commit_write

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:45 -07:00
Miklos Szeredi
9e6268db49 [PATCH] FUSE - read-write operations
This patch adds the write filesystem operations of FUSE.

The following operations are added:

 o setattr
 o symlink
 o mknod
 o mkdir
 o create
 o unlink
 o rmdir
 o rename
 o link

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:45 -07:00
Miklos Szeredi
e5e5558e92 [PATCH] FUSE - read-only operations
This patch adds the read-only filesystem operations of FUSE.

This contains the following files:

 o dir.c
    - directory, symlink and file-inode operations

The following operations are added:

 o lookup
 o getattr
 o readlink
 o follow_link
 o directory open
 o readdir
 o directory release
 o permission
 o dentry revalidate
 o statfs

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:45 -07:00
Miklos Szeredi
334f485df8 [PATCH] FUSE - device functions
This adds the FUSE device handling functions.

This contains the following files:

 o dev.c
    - fuse device operations (read, write, release, poll)
    - registers misc device
    - support for sending requests to userspace

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:44 -07:00
Miklos Szeredi
d8a5ba4545 [PATCH] FUSE - core
This patch adds FUSE core.

This contains the following files:

 o inode.c
    - superblock operations (alloc_inode, destroy_inode, read_inode,
      clear_inode, put_super, show_options)
    - registers FUSE filesystem

 o fuse_i.h
    - private header file

Requirements
============

 The most important difference between orinary filesystems and FUSE is
 the fact, that the filesystem data/metadata is provided by a userspace
 process run with the privileges of the mount "owner" instead of the
 kernel, or some remote entity usually running with elevated
 privileges.

 The security implication of this is that a non-privileged user must
 not be able to use this capability to compromise the system.  Obvious
 requirements arising from this are:

  - mount owner should not be able to get elevated privileges with the
    help of the mounted filesystem

  - mount owner should not be able to induce undesired behavior in
    other users' or the super user's processes

  - mount owner should not get illegitimate access to information from
    other users' and the super user's processes

 These are currently ensured with the following constraints:

  1) mount is only allowed to directory or file which the mount owner
    can modify without limitation (write access + no sticky bit for
    directories)

  2) nosuid,nodev mount options are forced

  3) any process running with fsuid different from the owner is denied
     all access to the filesystem

 1) and 2) are ensured by the "fusermount" mount utility which is a
    setuid root application doing the actual mount operation.

 3) is ensured by a check in the permission() method in kernel

 I started thinking about doing 3) in a different way because Christoph
 H. made a big deal out of it, saying that FUSE is unacceptable into
 mainline in this form.

 The suggested use of private namespaces would be OK, but in their
 current form have many limitations that make their use impractical (as
 discussed in this thread).

 Suggested improvements that would address these limitations:

   - implement shared subtrees

   - allow a process to join an existing namespace (make namespaces
     first-class objects)

   - implement the namespace creation/joining in a PAM module

 With all that in place the check of owner against current->fsuid may
 be removed from the FUSE kernel module, without compromising the
 security requirements.

 Suid programs still interesting questions, since they get access even
 to the private namespace causing some information leak (exact
 order/timing of filesystem operations performed), giving some
 ptrace-like capabilities to unprivileged users.  BTW this problem is
 not strictly limited to the namespace approach, since suid programs
 setting fsuid and accessing users' files will succeed with the current
 approach too.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 14:03:44 -07:00