Jens Axboe <jens.axboe@xxxxxxxxxx> writes: > On Mon, Oct 20 2008, Jens Axboe wrote: >> On Sun, Oct 19 2008, Dmitri Monakhov wrote: >> > Block device write procedure is different from regular file: >> > - Actual write performed without i_mutex. >> > - It has no metadata, so generic_osync_inode(O_SYNCMETEDATA) can not livelock. >> > - We do not have to worry about S_ISUID/S_ISGID bits. >> >> I already did an O_DIRECT part of block device splicing [1], I'll fold >> this into the splice branch and double check with some testing. >> >> [1] http://git.kernel.dk/?p=linux-2.6-block.git;a=commitdiff;h=fbb724a0484aba938024d41ca1dd86337d2550c9;hp=08c7910b275a4c580ad646ae8654439c8dfae4c5 > > The below is what I merged. Note that I changed the naming and made the > function look a lot more like the other splice helpers, so it's more > apparent how it differs. Let me know if I can add you Signed-off-by to Off course yes. > this one (preferably after you test it as well :-) currently i'm testing this stuff. > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 4d154dc..083198a 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -1288,7 +1288,7 @@ new_bio: > * Splice to file opened with O_DIRECT. Bypass caching completely and > * just go direct-to-bio > */ > -static ssize_t __block_splice_write(struct pipe_inode_info *pipe, > +static ssize_t __block_splice_direct_write(struct pipe_inode_info *pipe, > struct file *out, loff_t *ppos, size_t len, > unsigned int flags) > { > @@ -1318,6 +1318,9 @@ static ssize_t __block_splice_write(struct pipe_inode_info *pipe, > if (bsd.bio) > submit_bio(WRITE, bsd.bio); > > + if (ret > 0) > + *ppos += ret; > + > return ret; > } > > @@ -1327,12 +1330,11 @@ static ssize_t block_splice_write(struct pipe_inode_info *pipe, > { > ssize_t ret; > > - if (out->f_flags & O_DIRECT) { > - ret = __block_splice_write(pipe, out, ppos, len, flags); > - if (ret > 0) > - *ppos += ret; > - } else > - ret = generic_file_splice_write(pipe, out, ppos, len, flags); > + if (out->f_flags & O_DIRECT) > + ret = __block_splice_direct_write(pipe, out, ppos, len, flags); > + else > + ret = generic_file_splice_write_file_nolock(pipe, out, ppos, > + len, flags); > > return ret; > } > diff --git a/fs/splice.c b/fs/splice.c > index 4108264..eb1e1ac 100644 > --- a/fs/splice.c > +++ b/fs/splice.c > @@ -788,6 +788,59 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, > } > > /** > + * generic_file_splice_write_file_nolock - splice data from a pipe to a file > + * @pipe: pipe info > + * @out: file to write to > + * @ppos: position in @out > + * @len: number of bytes to splice > + * @flags: splice modifier flags > + * > + * Description: > + * Will either move or copy pages (determined by @flags options) from > + * the given pipe inode to the given block device. > + * Note: this is like @generic_file_splice_write, except that we > + * don't bother locking the output file. Useful for splicing directly > + * to a block device. > + */ > +ssize_t generic_file_splice_write_file_nolock(struct pipe_inode_info *pipe, > + struct file *out, loff_t *ppos, > + size_t len, unsigned int flags) > +{ > + struct address_space *mapping = out->f_mapping; > + struct inode *inode = mapping->host; > + struct splice_desc sd = { > + .total_len = len, > + .flags = flags, > + .pos = *ppos, > + .u.file = out, > + }; > + ssize_t ret; > + > + mutex_lock(&pipe->inode->i_mutex); > + ret = __splice_from_pipe(pipe, &sd, pipe_to_file); > + mutex_unlock(&pipe->inode->i_mutex); > + > + if (ret > 0) { > + unsigned long nr_pages; > + > + *ppos += ret; > + nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; > + > + if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) { > + int er; > + > + er = sync_page_range_nolock(inode, mapping, *ppos, ret); > + if (er) > + ret = er; > + } > + balance_dirty_pages_ratelimited_nr(mapping, nr_pages); > + } > + > + return ret; > +} > +EXPORT_SYMBOL(generic_file_splice_write_file_nolock); > + > +/** > * generic_file_splice_write_nolock - generic_file_splice_write without mutexes > * @pipe: pipe info > * @out: file to write to > diff --git a/include/linux/fs.h b/include/linux/fs.h > index a6a625b..5c9b880 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1957,6 +1957,8 @@ extern ssize_t generic_file_splice_write(struct pipe_inode_info *, > struct file *, loff_t *, size_t, unsigned int); > extern ssize_t generic_file_splice_write_nolock(struct pipe_inode_info *, > struct file *, loff_t *, size_t, unsigned int); > +extern ssize_t generic_file_splice_write_file_nolock(struct pipe_inode_info *, > + struct file *, loff_t *, size_t, unsigned int); > extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, > struct file *out, loff_t *, size_t len, unsigned int flags); > extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
