linux.git/fs/open.c, branch v2.6.20

[PATCH] fdtable: Make fdarray and fdsets equal in size

2006-12-10T17:57:22+00:00

Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets.  The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).

In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.

Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal.  This
patch removes fdtable->max_fdset.  As an added bonus, most of the supporting
code becomes simpler.

Signed-off-by: Vadim Lobanov 
Cc: Christoph Hellwig 
Cc: Al Viro 
Cc: Dipankar Sarma 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] VFS: change struct file to use struct path

2006-12-08T16:28:41+00:00

This patch changes struct file to use struct path instead of having
independent pointers to struct dentry and struct vfsmount, and converts all
users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}.

Additionally, it adds two #define's to make the transition easier for users of
the f_dentry and f_vfsmnt.

Signed-off-by: Josef "Jeff" Sipek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] tty: ->signal->tty locking

2006-12-08T16:28:38+00:00

Fix the locking of signal->tty.

Use ->sighand->siglock to protect ->signal->tty; this lock is already used
by most other members of ->signal/->sighand.  And unless we are 'current'
or the tasklist_lock is held we need ->siglock to access ->signal anyway.

(NOTE: sys_unshare() is broken wrt ->sighand locking rules)

Note that tty_mutex is held over tty destruction, so while holding
tty_mutex any tty pointer remains valid.  Otherwise the lifetime of ttys
are governed by their open file handles.  This leaves some holes for tty
access from signal->tty (or any other non file related tty access).

It solves the tty SLAB scribbles we were seeing.

(NOTE: the change from group_send_sig_info to __group_send_sig_info needs to
       be examined by someone familiar with the security framework, I think
       it is safe given the SEND_SIG_PRIV from other __group_send_sig_info
       invocations)

[schwidefsky@de.ibm.com: 3270 fix]
[akpm@osdl.org: various post-viro fixes]
Signed-off-by: Peter Zijlstra 
Acked-by: Alan Cox 
Cc: Oleg Nesterov 
Cc: Prarit Bhargava 
Cc: Chris Wright 
Cc: Roland McGrath 
Cc: Stephen Smalley 
Cc: James Morris 
Cc: "David S. Miller" 
Cc: Jeff Dike 
Cc: Martin Schwidefsky 
Cc: Jan Kara 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] r/o bind mounts: prepare for write access checks: collapse if()

2006-10-01T07:39:30+00:00

We're shortly going to be adding a bunch more permission checks in these
functions.  That requires adding either a bunch of new if() conditions, or
some gotos.  This patch collapses existing if()s and uses gotos instead to
prepare for the upcoming changes.

Signed-off-by: Dave Hansen 
Acked-by: Christoph Hellwig 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Create fs/utimes.c

2006-10-01T07:39:19+00:00

* fs/open.c is getting bit crowdy
* preparation to lutimes(2)

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fix wrong error code on interrupted close syscalls

2006-09-29T16:18:13+00:00

The problem is that close() syscalls can call a file system's flush
handler, which in turn might sleep interruptibly and ultimately pass back
an -ERESTARTSYS return value.  This happens for files backed by an
interruptible NFS mount under nfs_file_flush() when a large file has just
been written and nfs_wait_bit_interruptible() detects that there is a
signal pending.

I have a test case where the "strace" command is used to attach to a
process sleeping in such a close().  Since the SIGSTOP is forced onto the
victim process (removing it from the thread's "blocked" mask in
force_sig_info()), the RPC wait is interrupted and the close() is
terminated early.

But the file table entry has already been cleared before the flush handler
was called.  Thus, when the syscall is restarted, the file descriptor
appears closed and an EBADF error is returned (which is wrong).  What's
worse, there is the hypothetical case where another thread of a
multi-threaded application might have reused the file descriptor, in which
case that file would be mistakenly closed.

The bottom line is that close() syscalls are not restartable, and thus
-ERESTARTSYS return values should be mapped to -EINTR.  This is consistent
with the close(2) manual page.  The fix is below.

Signed-off-by: Ernie Petrides 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] vfs: define new lookup flag for chdir

2006-09-29T16:18:08+00:00

In the "operation does permission checking" model used by fuse, chdir
permission is not checked, since there's no chdir method.

For this case set a lookup flag, which will be passed to ->permission(), so
fuse can distinguish it from permission checks for other operations.

Signed-off-by: Miklos Szeredi 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] ftruncate does not always update m/ctime

2006-06-25T17:01:15+00:00

In the course of trying to track down a bug where a file mtime was not
being updated correctly, it was discovered that the m/ctime updates were
not quite being handled correctly for ftruncate() calls.

Quoth SUSv3:

open(2):

        If O_TRUNC is set and the file did previously exist, upon
        successful completion, open() shall mark for update the st_ctime
        and st_mtime fields of the file.

truncate(2):

        Upon successful completion, if the file size is changed, this
        function shall mark for update the st_ctime and st_mtime fields
        of the file, and the S_ISUID and S_ISGID bits of the file mode
        may be cleared.

ftruncate(2):

        Upon successful completion, if fildes refers to a regular file,
        the ftruncate() function shall mark for update the st_ctime and
        st_mtime fields of the file and the S_ISUID and S_ISGID bits of
        the file mode may be cleared. If the ftruncate() function is
        unsuccessful, the file is unaffected.

The open(O_TRUNC) and truncate cases were being handled correctly, but the
ftruncate case was being handled like the truncate case.  The semantics of
truncate and ftruncate don't quite match, so ftruncate needs to be handled
slightly differently.

The attached patch addresses this issue for ftruncate(2).

My thanx to Stephen Tweedie and Trond Myklebust for their help in
understanding the situation and semantics.

Signed-off-by: Peter Staubach 
Cc: "Stephen C. Tweedie" 
Cc: Trond Myklebust 
Cc: Al Viro 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] vfs: add lock owner argument to flush operation

2006-06-23T14:43:02+00:00

Pass the POSIX lock owner ID to the flush operation.

This is useful for filesystems which don't want to store any locking state
in inode->i_flock but want to handle locking/unlocking POSIX locks
internally.  FUSE is one such filesystem but I think it possible that some
network filesystems would need this also.

Also add a flag to indicate that a POSIX locking request was generated by
close(), so filesystems using the above feature won't send an extra locking
request in this case.

Signed-off-by: Miklos Szeredi 
Cc: Trond Myklebust 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] VFS: Permit filesystem to perform statfs with a known root dentry

2006-06-23T14:42:45+00:00

Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.

This complements the get_sb() patch.  That reduced the significance of
sb->s_root, allowing NFS to place a fake root there.  However, NFS does
require a dentry to use as a target for the statfs operation.  This permits
the root in the vfsmount to be used instead.

linux/mount.h has been added where necessary to make allyesconfig build
successfully.

Interest has also been expressed for use with the FUSE and XFS filesystems.

Signed-off-by: David Howells 
Acked-by: Al Viro 
Cc: Nathan Scott 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds