linux.git/fs/file_table.c, branch v2.6.27

[PATCH] f_count may wrap around

2008-07-27T00:53:40+00:00

make it atomic_long_t; while we are at it, get rid of useless checks in affs,
hfs and hpfs - ->open() always has it equal to 1, ->release() - to 0.

Signed-off-by: Al Viro

[PATCH] split linux/file.h

2008-05-01T17:08:16+00:00

Initial splitoff of the low-level stuff; taken to fdtable.h

Signed-off-by: Al Viro

[PATCH] r/o bind mounts: debugging for missed calls

2008-04-19T04:29:28+00:00

There have been a few oopses caused by 'struct file's with NULL f_vfsmnts.
There was also a set of potentially missed mnt_want_write()s from
dentry_open() calls.

This patch provides a very simple debugging framework to catch these kinds of
bugs.  It will WARN_ON() them, but should stop us from having any oopses or
mnt_writer count imbalances.

I'm quite convinced that this is a good thing because it found bugs in the
stuff I was working on as soon as I wrote it.

[hch: made it conditional on a debug option.
      But it's still a little bit too ugly]

[hch: merged forced remount r/o fix from Dave and akpm's fix for the fix]

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

[PATCH] r/o bind mounts: elevate write count for open()s

2008-04-19T04:29:25+00:00

This is the first really tricky patch in the series.  It elevates the writer
count on a mount each time a non-special file is opened for write.

We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps.  This will cover even those cases, while a
call in may_open() would not have.

There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.

Some filesystems forego the use of normal vfs calls to create
struct files.   Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.

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

[PATCH] r/o bind mounts: create helper to drop file write access

2008-04-19T04:25:32+00:00

If someone decides to demote a file from r/w to just
r/o, they can use this same code as __fput().

NFS does just that, and will use this in the next
patch.

AV: drop write access in __fput() only after we evict from file list.

Signed-off-by: Dave Hansen 
Cc: Erez Zadok 
Cc: Trond Myklebust 
Cc: "J Bruce Fields" 
Acked-by: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

[PATCH] fix up new filp allocators

2008-03-19T10:54:05+00:00

Some new uses of get_empty_filp() have crept in; switched
to alloc_file() to make sure that pieces of initialization
won't be missing.

We really need to kill get_empty_filp().

[AV] fixed dentry leak on failure exit in anon_inode_getfd()

Cc: Erez Zadok 
Cc: Trond Myklebust 
Cc: "J Bruce Fields" 
Acked-by: Al Viro 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Hansen 
Signed-off-by: Al Viro

fs: remove fastcall, it is always empty

2008-02-08T17:22:31+00:00

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs/file_table.c: use list_for_each_entry() instead of list_for_each()

2007-10-19T18:53:38+00:00

fs/file_table.c: use list_for_each_entry() instead of list_for_each()
in fs_may_remount_ro()

Signed-off-by: Matthias Kaehlcke 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

r/o bind mounts: filesystem helpers for custom 'struct file's

2007-10-17T15:43:04+00:00

Why do we need r/o bind mounts?

This feature allows a read-only view into a read-write filesystem.  In the
process of doing that, it also provides infrastructure for keeping track of
the number of writers to any given mount.

This has a number of uses.  It allows chroots to have parts of filesystems
writable.  It will be useful for containers in the future because users may
have root inside a container, but should not be allowed to write to
somefilesystems.  This also replaces patches that vserver has had out of the
tree for several years.

It allows security enhancement by making sure that parts of your filesystem
read-only (such as when you don't trust your FTP server), when you don't want
to have entire new filesystems mounted, or when you want atime selectively
updated.  I've been using the following script to test that the feature is
working as desired.  It takes a directory and makes a regular bind and a r/o
bind mount of it.  It then performs some normal filesystem operations on the
three directories, including ones that are expected to fail, like creating a
file on the r/o mount.

This patch:

Some filesystems forego the vfs and may_open() and create their own 'struct
file's.

This patch creates a couple of helper functions which can be used by these
filesystems, and will provide a unified place which the r/o bind mount code
may patch.

Also, rename an existing, static-scope init_file() to a less generic name.

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

fs: use kmem_cache_zalloc instead

2007-10-17T15:42:48+00:00

Signed-off-by: Denis Cheng 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds