linux-toradex.git/fs/open.c, branch v2.6.18

[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

[PATCH] log more info for directory entry change events

2006-06-20T09:25:28+00:00

When an audit event involves changes to a directory entry, include
a PATH record for the directory itself.  A few other notable changes:

    - fixed audit_inode_child() hooks in fsnotify_move()
    - removed unused flags arg from audit_inode()
    - added audit log routines for logging a portion of a string

Here's some sample output.

before patch:
type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255
type=CWD msg=audit(1149821605.320:26):  cwd="/root"
type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0

after patch:
type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255
type=CWD msg=audit(1149822032.332:24):  cwd="/root"
type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0
type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0

Signed-off-by: Amy Griffis 
Signed-off-by: Al Viro

[PATCH] fs/open.c: unexport sys_openat

2006-05-15T18:20:54+00:00

Remove the unused EXPORT_SYMBOL_GPL(sys_openat).

Signed-off-by: Adrian Bunk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86: be careful about tailcall breakage for sys_open[at] too

2006-04-18T20:22:59+00:00

Came up through a quick grep for other cases similar to the ftruncate()
one in commit 0a489cb3b6a7b277030cdbc97c2c65905db94536.

Also, add a comment, so that people who read the code understand why we
do what looks like a no-op.

(Again, this won't actually matter to any sane user, since libc will
save and restore the register gcc stomps on, but it's still wrong to
stomp on it)

Signed-off-by: Linus Torvalds

x86: don't allow tail-calls in sys_ftruncate[64]()

2006-04-18T20:02:48+00:00

Gcc thinks it owns the incoming argument stack, but that's not true for
"asmlinkage" functions, and it corrupts the caller-set-up argument stack
when it pushes the third argument onto the stack.  Which can result in
%ebx getting corrupted in user space.

Now, normally nobody sane would ever notice, since libc will save and
restore %ebx anyway over the system call, but it's still wrong.

I'd much rather have "asmlinkage" tell gcc directly that it doesn't own
the stack, but no such attribute exists, so we're stuck with our hacky
manual "prevent_tail_call()" macro once more (we've had the same issue
before with sys_waitpid() and sys_wait4()).

Thanks to Hans-Werner Hilse  for reporting
the issue and testing the fix.

Signed-off-by: Linus Torvalds

Merge branch 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current

2006-03-25T17:24:53+00:00

* 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: (22 commits)
  [PATCH] fix audit_init failure path
  [PATCH] EXPORT_SYMBOL patch for audit_log, audit_log_start, audit_log_end and audit_format
  [PATCH] sem2mutex: audit_netlink_sem
  [PATCH] simplify audit_free() locking
  [PATCH] Fix audit operators
  [PATCH] promiscuous mode
  [PATCH] Add tty to syscall audit records
  [PATCH] add/remove rule update
  [PATCH] audit string fields interface + consumer
  [PATCH] SE Linux audit events
  [PATCH] Minor cosmetic cleanups to the code moved into auditfilter.c
  [PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL
  [PATCH] Fix IA64 success/failure indication in syscall auditing.
  [PATCH] Miscellaneous bug and warning fixes
  [PATCH] Capture selinux subject/object context information.
  [PATCH] Exclude messages by message type
  [PATCH] Collect more inode information during syscall processing.
  [PATCH] Pass dentry, not just name, in fsnotify creation hooks.
  [PATCH] Define new range of userspace messages.
  [PATCH] Filter rule comparators
  ...

Fixed trivial conflict in security/selinux/hooks.c

[PATCH] Add lookup_instantiate_filp usage warning

2006-03-25T16:22:51+00:00

I think it would be nice to put an usage warning in header of
lookup_instantiate_filp() to indicate it is unsafe to use it on anything
but regular files (even that is potentially unsafe, but there your ->open()
is usually in your hands anyway), so that others won't fall into the same
trap I did.

Signed-off-by: Oleg Drokin 
Cc: Trond Myklebust 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Shrinks sizeof(files_struct) and better layout

2006-03-23T15:38:09+00:00

1) Reduce the size of (struct fdtable) to exactly 64 bytes on 32bits
   platforms, lowering kmalloc() allocated space by 50%.

2) Reduce the size of (files_struct), using a special 32 bits (or
   64bits) embedded_fd_set, instead of a 1024 bits fd_set for the
   close_on_exec_init and open_fds_init fields.  This save some ram (248
   bytes per task) as most tasks dont open more than 32 files.  D-Cache
   footprint for such tasks is also reduced to the minimum.

3) Reduce size of allocated fdset.  Currently two full pages are
   allocated, that is 32768 bits on x86 for example, and way too much.  The
   minimum is now L1_CACHE_BYTES.

UP and SMP should benefit from this patch, because most tasks will touch
only one cache line when open()/close() stdin/stdout/stderr (0/1/2),
(next_fd, close_on_exec_init, open_fds_init, fd_array[0 ..  2] being in the
same cache line)

Signed-off-by: Eric Dumazet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds