linux.git/fs/splice.c, branch v2.6.22-rc4

[PATCH] splice: always call into page_cache_readahead()

2007-05-08T06:46:19+00:00

Don't try to guess what the read-ahead logic will do, allow it
to make its own decisions.

Signed-off-by: Jens Axboe

[PATCH] splice(): fix interaction with readahead

2007-05-08T06:44:36+00:00

Eric Dumazet, thank you for disclosing this bug.

Readahead logic somehow fails to populate the page range with data.
It can be because

1) the readahead routine is not always called in the following lines of

fs/splice.c:
        if (!loff || nr_pages > 1)
                page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);

2) even called, page_cache_readahead() wont guarantee the pages are there.
It wont submit readahead I/O for pages already in the radix tree, or when
(ra_pages == 0), or after 256 cache hits.

In your case, it should be because of the retried reads, which lead to
excessive cache hits, and disables readahead at some time.

And that _one_ failure of readahead blocks the whole read process.
The application receives EAGAIN and retries the read, but
__generic_file_splice_read() refuse to make progress:

- in the previous invocation, it has allocated a blank page and inserted it
  into the radix tree, but never has the chance to start I/O for it: the test
  of SPLICE_F_NONBLOCK goes before that.

- in the retried invocation, the readahead code will neither get out of the
  cache hit mode, nor will it submit I/O for an already existing page.

Cc: Eric Dumazet 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

[PATCH] splice: partial write fix

2007-03-29T12:26:42+00:00

Currently if partial write has happened while ->commit_write() then page
wasn't marked as accessed and rebalanced.

Signed-off-by: Monakhov Dmitriy 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

Export __splice_from_pipe()

2007-03-27T06:55:47+00:00

Ocfs2 wants to implement it's own splice write actor so that it can better
manage cluster / page locks. This lets us re-use the rest of splice write
while only providing our own code where it's actually important.

Signed-off-by: Mark Fasheh 
Signed-off-by: Jens Axboe

2/2 splice: dont readpage

2007-03-27T06:55:39+00:00

Splice does not need to readpage to bring the page uptodate before writing
to it, because prepare_write will take care of that for us.

Splice is also wrong to SetPageUptodate before the page is actually uptodate.
This results in the old uninitialised memory leak. This gets fixed as a
matter of course when removing the readpage logic.

Signed-off-by: Nick Piggin 
Signed-off-by: Jens Axboe

1/2 splice: dont steal

2007-03-27T06:55:08+00:00

Stealing pages with splice is problematic because we cannot just insert
an uptodate page into the pagecache and hope the filesystem can take care
of it later.

We also cannot just ClearPageUptodate, then hope prepare_write does not
write anything into the page, because I don't think prepare_write gives
that guarantee.

Remove support for SPLICE_F_MOVE for now. If we really want to bring it
back, we might be able to do so with a the new filesystem buffered write
aops APIs I'm working on. If we really don't want to bring it back, then
we should decide that sooner rather than later, and remove the flag and
all the stealing infrastructure before anybody starts using it.

Signed-off-by: Nick Piggin 
Signed-off-by: Jens Axboe

[PATCH] constify pipe_buf_operations

2006-12-13T17:05:47+00:00

- pipe/splice should use const pipe_buf_operations and file_operations

- struct pipe_inode_info has an unused field "start" : get rid of it.

Signed-off-by: Eric Dumazet 
Cc: Jens Axboe 
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] splice: fix problem introduced with inode diet

2006-11-04T16:45:39+00:00

After the inode slimming patch that unionised i_pipe/i_bdev/i_cdev, it's
no longer enough to check for existance of ->i_pipe to verify that this
is a pipe.

Original patch from Eric Dumazet 
Final solution suggested by Linus.

Signed-off-by: Jens Axboe 
Signed-off-by: Linus Torvalds

[PATCH] mm: clean up pagecache allocation

2006-10-28T18:30:50+00:00

- Consolidate page_cache_alloc

- Fix splice: only the pagecache pages and filesystem data need to use
  mapping_gfp_mask.

- Fix grab_cache_page_nowait: same as splice, also honour NUMA placement.

Signed-off-by: Nick Piggin 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds