linux-toradex.git/fs/splice.c, branch v2.6.22.4

splice: fix double page unlock

2007-08-09T21:27:32+00:00

If add_to_page_cache_lru() fails, the page will not be locked. But
splice jumps to an error path that does a page release and unlock,
causing a BUG() in unlock_page().

Fix this by adding one more label that just releases the page. This bug
was actually triggered on EL5 by gurudas pai 
using fio.

Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

splice: only check do_wakeup in splice_to_pipe() for a real pipe

2007-06-15T11:16:13+00:00

We only ever set do_wakeup to non-zero if the pipe has an inode
backing, so it's pointless to check outside the pipe->inode
check.

Signed-off-by: Jens Axboe

splice: fix leak of pages on short splice to pipe

2007-06-15T11:14:22+00:00

If the destination pipe is full and we already transferred
data, we break out instead of waiting for more pipe room.
The exit logic looks at spd->nr_pages to see if we moved
everything inside the spd container, but we decrement that
variable in the loop to decide when spd has emptied.

Instead we want to compare to the original page count in
the spd, so cache that in a local variable.

Signed-off-by: Jens Axboe

splice: adjust balance_dirty_pages_ratelimited() call

2007-06-15T11:10:37+00:00

As we have potentially dirtied more than 1 page, we should indicate as
such to the dirty page balancing. So call
balance_dirty_pages_ratelimited_nr() and pass in the approximate number
of pages we dirtied.

Signed-off-by: Jens Axboe

splice: __generic_file_splice_read: fix read/truncate race

2007-06-08T06:34:11+00:00

Original patch and description from Neil Brown ,
merged and adapted to splice branch by me. Neils text follows:

__generic_file_splice_read() currently samples the i_size at the start
and doesn't do so again unless it needs to call ->readpage to load
a page.  After ->readpage it has to re-sample i_size as a truncate
may have caused that page to be filled with zeros, and the read()
call should not see these.

However there are other activities that might cause ->readpage to be
called on a page between the time that __generic_file_splice_read()
samples i_size and when it finds that it has an uptodate page. These
include at least read-ahead and possibly another thread performing a
read

So we must sample i_size *after* it has an uptodate page.  Thus the
current sampling at the start and after a read can be replaced with a
sampling before page addition into spd.

Signed-off-by: Jens Axboe

splice: __generic_file_splice_read: fix i_size_read() length checks

2007-06-08T06:34:05+00:00

__generic_file_splice_read's partial page check, at eof after readpage,
not only got its calculations wrong, but also reused the loff variable:
causing data corruption when splicing from a non-0 offset in the file's
last page (revealed by ext2 -b 1024 testing on a loop of a tmpfs file).

Signed-off-by: Hugh Dickins 
Signed-off-by: Jens Axboe

splice: move balance_dirty_pages_ratelimited() outside of splice actor

2007-06-08T06:33:59+00:00

I've seen inode related deadlocks, so move this call outside of the
actor itself, which may hold the inode lock.

Signed-off-by: Jens Axboe

splice: remove do_splice_direct() symbol export

2007-06-08T06:33:41+00:00

It's only supposed to be used by do_sendfile(), which is never
modular. So kill the export.

Signed-off-by: Jens Axboe

splice: move inode size check into generic_file_splice_read()

2007-06-08T06:32:38+00:00

Signed-off-by: Jens Axboe

[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