linux-toradex.git/fs/libfs.c, branch v2.6.28.1

fs: symlink write_begin allocation context fix

2009-01-18T18:43:46+00:00

commit 54566b2c1594c2326a645a3551f9d989f7ba3c5e upstream.

With the write_begin/write_end aops, page_symlink was broken because it
could no longer pass a GFP_NOFS type mask into the point where the
allocations happened.  They are done in write_begin, which would always
assume that the filesystem can be entered from reclaim.  This bug could
cause filesystem deadlocks.

The funny thing with having a gfp_t mask there is that it doesn't really
allow the caller to arbitrarily tinker with the context in which it can be
called.  It couldn't ever be GFP_ATOMIC, for example, because it needs to
take the page lock.  The only thing any callers care about is __GFP_FS
anyway, so turn that into a single flag.

Add a new flag for write_begin, AOP_FLAG_NOFS.  Filesystems can now act on
this flag in their write_begin function.  Change __grab_cache_page to
accept a nofs argument as well, to honour that flag (while we're there,
change the name to grab_cache_page_write_begin which is more instructive
and does away with random leading underscores).

This is really a more flexible way to go in the end anyway -- if a
filesystem happens to want any extra allocations aside from the pagecache
ones in ints write_begin function, it may now use GFP_KERNEL (rather than
GFP_NOFS) for common case allocations (eg.  ocfs2_alloc_write_ctxt, for a
random example).

[kosaki.motohiro@jp.fujitsu.com: fix ubifs]
[kosaki.motohiro@jp.fujitsu.com: fix fuse]
Signed-off-by: Nick Piggin 
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
[ Cleaned up the calling convention: just pass in the AOP flags
  untouched to the grab_cache_page_write_begin() function.  That
  just simplifies everybody, and may even allow future expansion of the
  logic.   - Linus ]
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fs: remove prepare_write/commit_write

2008-10-30T18:38:45+00:00

Nothing uses prepare_write or commit_write. Remove them from the tree
completely.

[akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting]
Signed-off-by: Nick Piggin 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] new helper: d_obtain_alias

2008-10-23T09:13:00+00:00

The calling conventions of d_alloc_anon are rather unfortunate for all
users, and it's name is not very descriptive either.

Add d_obtain_alias as a new exported helper that drops the inode
reference in the failure case, too and allows to pass-through NULL
pointers and inodes to allow for tail-calls in the export operations.

Incidentally this helper already existed as a private function in
libfs.c as exportfs_d_alloc so kill that one and switch the callers
to d_obtain_alias.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

VFS: increase pseudo-filesystem block size to PAGE_SIZE

2008-07-30T16:41:44+00:00

This commit:

    commit ba52de123d454b57369f291348266d86f4b35070
    Author: Theodore Ts'o 
    Date:   Wed Sep 27 01:50:49 2006 -0700

        [PATCH] inode-diet: Eliminate i_blksize from the inode structure

caused the block size used by pseudo-filesystems to decrease from
PAGE_SIZE to 1024 leading to a doubling of the number of context switches
during a kernbench run.

Signed-off-by: Alex Nixon 
Cc: Andi Kleen 
Cc: Jeremy Fitzhardinge 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Ian Campbell 
Cc: "Theodore Ts'o" 
Cc: Alexander Viro 
Cc: Hugh Dickins 
Cc: Jens Axboe 
Cc: 		[2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

add kernel-doc for simple_read_from_buffer and memory_read_from_buffer

2008-07-04T17:40:07+00:00

Add kernel-doc comments describing simple_read_from_buffer and
memory_read_from_buffer.

Signed-off-by: Akinobu Mita 
Cc: Christoph Hellwig 
Cc: "Randy.Dunlap" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

introduce memory_read_from_buffer()

2008-06-06T18:29:11+00:00

This patch introduces memory_read_from_buffer().

The only difference between memory_read_from_buffer() and
simple_read_from_buffer() is which address space the function copies to.

simple_read_from_buffer copies to user space memory.
memory_read_from_buffer copies to normal memory.

Signed-off-by: Akinobu Mita 
Cc: Al Viro 
Cc: Doug Warzecha 
Cc: Zhang Rui 
Cc: Matt Domsch 
Cc: Abhay Salunke 
Cc: Greg Kroah-Hartman 
Cc: Markus Rechberger 
Cc: Kay Sievers 
Cc: Bob Moore 
Cc: Thomas Renninger 
Cc: Len Brown 
Cc: Benjamin Herrenschmidt 
Cc: "Antonino A. Daplas" 
Cc: Krzysztof Helt 
Cc: Geert Uytterhoeven 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Peter Oberparleiter 
Cc: Michael Holzheu 
Cc: Brian King 
Cc: James E.J. Bottomley 
Cc: Andrew Vasquez 
Cc: Seokmann Ju 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

libfs: rename simple_attr_close to simple_attr_release

2008-02-08T17:22:34+00:00

simple_attr_close implementes ->release so it should be named accordingly.

Signed-off-by: Christoph Hellwig 
Cc: 
Cc: Arnd Bergmann 
Cc: Greg KH 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

libfs: make simple attributes interruptible

2008-02-08T17:22:34+00:00

Use mutex_lock_interruptible in simple_attr_read/write.

Signed-off-by: Christoph Hellwig 
Cc: 
Cc: Arnd Bergmann 
Cc: Greg KH 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

libfs: allow error return from simple attributes

2008-02-08T17:22:34+00:00

Sometimes simple attributes might need to return an error, e.g. for
acquiring a mutex interruptibly.  In fact we have that situation in
spufs already which is the original user of the simple attributes.  This
patch merged the temporarily forked attributes in spufs back into the
main ones and allows to return errors.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Christoph Hellwig 
Cc: 
Cc: Arnd Bergmann 
Cc: Greg KH 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Pagecache zeroing: zero_user_segment, zero_user_segments and zero_user

2008-02-05T17:44:13+00:00

Simplify page cache zeroing of segments of pages through 3 functions

zero_user_segments(page, start1, end1, start2, end2)

        Zeros two segments of the page. It takes the position where to
        start and end the zeroing which avoids length calculations and
	makes code clearer.

zero_user_segment(page, start, end)

        Same for a single segment.

zero_user(page, start, length)

        Length variant for the case where we know the length.

We remove the zero_user_page macro. Issues:

1. Its a macro. Inline functions are preferable.

2. The KM_USER0 macro is only defined for HIGHMEM.

   Having to treat this special case everywhere makes the
   code needlessly complex. The parameter for zeroing is always
   KM_USER0 except in one single case that we open code.

Avoiding KM_USER0 makes a lot of code not having to be dealing
with the special casing for HIGHMEM anymore. Dealing with
kmap is only necessary for HIGHMEM configurations. In those
configurations we use KM_USER0 like we do for a series of other
functions defined in highmem.h.

Since KM_USER0 is depends on HIGHMEM the existing zero_user_page
function could not be a macro. zero_user_* functions introduced
here can be be inline because that constant is not used when these
functions are called.

Also extract the flushing of the caches to be outside of the kmap.

[akpm@linux-foundation.org: fix nfs and ntfs build]
[akpm@linux-foundation.org: fix ntfs build some more]
Signed-off-by: Christoph Lameter 
Cc: Steven French 
Cc: Michael Halcrow 
Cc: 
Cc: Steven Whitehouse 
Cc: Trond Myklebust 
Cc: "J. Bruce Fields" 
Cc: Anton Altaparmakov 
Cc: Mark Fasheh 
Cc: David Chinner 
Cc: Michael Halcrow 
Cc: Steven French 
Cc: Steven Whitehouse 
Cc: Trond Myklebust 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds