linux.git/fs/splice.c, branch v2.6.34

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

sendfile(): check f_op.splice_write() rather than f_op.sendpage()

2009-11-04T08:09:52+00:00

sendfile(2) was reworked with the splice infrastructure, but it still
checks f_op.sendpage() instead of f_op.splice_write() wrongly.  Although
if f_op.sendpage() exists, f_op.splice_write() always exists at the same
time currently, the assumption will be broken in future silently.  This
patch also brings a side effect: sendfile(2) can work with any output
file.  Some security checks related to f_op are added too.

Signed-off-by: Changli Gao 
Signed-off-by: Jens Axboe

Merge branch 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block

2009-09-15T00:55:15+00:00

* 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block: (29 commits)
  block: use blkdev_issue_discard in blk_ioctl_discard
  Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads
  block: don't assume device has a request list backing in nr_requests store
  block: Optimal I/O limit wrapper
  cfq: choose a new next_req when a request is dispatched
  Seperate read and write statistics of in_flight requests
  aoe: end barrier bios with EOPNOTSUPP
  block: trace bio queueing trial only when it occurs
  block: enable rq CPU completion affinity by default
  cfq: fix the log message after dispatched a request
  block: use printk_once
  cciss: memory leak in cciss_init_one()
  splice: update mtime and atime on files
  block: make blk_iopoll_prep_sched() follow normal 0/1 return convention
  cfq-iosched: get rid of must_alloc flag
  block: use interrupts disabled version of raise_softirq_irqoff()
  block: fix comment in blk-iopoll.c
  block: adjust default budget for blk-iopoll
  block: fix long lines in block/blk-iopoll.c
  block: add blk-iopoll, a NAPI like approach for block devices
  ...

vfs: Introduce new helpers for syncing after writing to O_SYNC file or IS_SYNC inode

2009-09-14T15:08:15+00:00

Introduce new function for generic inode syncing (vfs_fsync_range) and use
it from fsync() path. Introduce also new helper for syncing after a sync
write (generic_write_sync) using the generic function.

Use these new helpers for syncing from generic VFS functions. This makes
O_SYNC writes to block devices acquire i_mutex for syncing. If we really
care about this, we can make block_fsync() drop the i_mutex and reacquire
it before it returns.

CC: Evgeniy Polyakov 
CC: ocfs2-devel@oss.oracle.com
CC: Joel Becker 
CC: Felix Blyakher 
CC: xfs@oss.sgi.com
CC: Anton Altaparmakov 
CC: linux-ntfs-dev@lists.sourceforge.net
CC: OGAWA Hirofumi 
CC: linux-ext4@vger.kernel.org
CC: tytso@mit.edu
Acked-by: Christoph Hellwig 
Signed-off-by: Jan Kara

splice: update mtime and atime on files

2009-09-11T12:34:33+00:00

Splice should update the modification and access times on regular
files just like read and write. Not updating mtime will confuse
backup tools, etc...

This patch only adds the time updates for regular files.  For pipes
and other special files that splice touches the need for updating the
times is less clear.  Let's discuss and fix that separately.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Jens Axboe

splice: fix kmaps in default_file_splice_write()

2009-05-19T09:37:46+00:00

Unfortunately multiple kmap() within a single thread are deadlockable,
so writing out multiple buffers with writev() isn't possible.

Change the implementation so that it does a separate write() for each
buffer.  This actually simplifies the code a lot since the
splice_from_pipe() helper can be used.

This limitation is caused by HIGHMEM pages, and so only affects a
subset of architectures and configurations.  In the future it may be
worth to implement default_file_splice_write() in a more efficient way
on configs that allow it.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Jens Axboe

splice: fix error return code

2009-05-14T07:49:44+00:00

fs/splice.c: In function 'default_file_splice_read':
fs/splice.c:566: warning: 'error' may be used uninitialized in this function

which is sort-of true.  The code will in fact return -ENOMEM instead of the
kernel_readv() return value.

Cc: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

splice: fix repeated kmap()'s in default_file_splice_read()

2009-05-13T06:35:35+00:00

We cannot reliably map more than one page at the time, or we risk
deadlocking. Just allocate the pages from low mem instead.

Reported-by: Andrew Morton 
Signed-off-by: Jens Axboe

splice: implement default splice_write method

2009-05-11T12:13:10+00:00

If f_op->splice_write() is not implemented, fall back to a plain write.
Use vfs_writev() to write from the pipe buffers.

This will allow splice on all filesystems and file types.  This
includes "direct_io" files in fuse which bypass the page cache.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Jens Axboe

splice: implement default splice_read method

2009-05-11T12:13:10+00:00

If f_op->splice_read() is not implemented, fall back to a plain read.
Use vfs_readv() to read into previously allocated pages.

This will allow splice and functions using splice, such as the loop
device, to work on all filesystems.  This includes "direct_io" files
in fuse which bypass the page cache.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Jens Axboe