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author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2008-06-10 18:31:00 -0400 |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2008-07-09 12:08:45 -0400 |
commit | efc91ed0191e3fc62bb1c556ac93fc4e661214d2 (patch) | |
tree | 291dba382da5d609c5bd35b5e369324ecbb95c00 /fs/nfs/file.c | |
parent | b390c2b55c830eb3b64633fa8d8b8837e073e458 (diff) | |
download | kernel_samsung_smdk4412-efc91ed0191e3fc62bb1c556ac93fc4e661214d2.zip kernel_samsung_smdk4412-efc91ed0191e3fc62bb1c556ac93fc4e661214d2.tar.gz kernel_samsung_smdk4412-efc91ed0191e3fc62bb1c556ac93fc4e661214d2.tar.bz2 |
NFS: Optimise append writes with holes
If a file is being extended, and we're creating a hole, we might as well
declare the entire page to be up to date.
This patch significantly improves the write performance for sparse files
in the case where lseek(SEEK_END) is used to append several non-contiguous
writes at intervals of < PAGE_SIZE.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/file.c')
-rw-r--r-- | fs/nfs/file.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 7c73f06..7ac89a8 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -344,6 +344,26 @@ static int nfs_write_end(struct file *file, struct address_space *mapping, unsigned offset = pos & (PAGE_CACHE_SIZE - 1); int status; + /* + * Zero any uninitialised parts of the page, and then mark the page + * as up to date if it turns out that we're extending the file. + */ + if (!PageUptodate(page)) { + unsigned pglen = nfs_page_length(page); + unsigned end = offset + len; + + if (pglen == 0) { + zero_user_segments(page, 0, offset, + end, PAGE_CACHE_SIZE); + SetPageUptodate(page); + } else if (end >= pglen) { + zero_user_segment(page, end, PAGE_CACHE_SIZE); + if (offset == 0) + SetPageUptodate(page); + } else + zero_user_segment(page, pglen, PAGE_CACHE_SIZE); + } + lock_kernel(); status = nfs_updatepage(file, page, offset, copied); unlock_kernel(); |