From 7263cebed9fadad719063fdc8bba7085cf2c080d Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Mon, 28 Feb 2011 17:03:58 +0530 Subject: fs/9p: Add buffered write support for v9fs. We can now support writeable mmaps. Based on the original patch from Badari Pulavarty Signed-off-by: Aneesh Kumar K.V Signed-off-by: Venkateswararao Jujjuri Signed-off-by: Eric Van Hensbergen --- fs/9p/vfs_addr.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 168 insertions(+), 15 deletions(-) (limited to 'fs/9p/vfs_addr.c') diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index 637bd703e28c..566684ce55e2 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -39,16 +39,16 @@ #include "v9fs.h" #include "v9fs_vfs.h" #include "cache.h" +#include "fid.h" /** - * v9fs_vfs_readpage - read an entire page in from 9P + * v9fs_fid_readpage - read an entire page in from 9P * - * @filp: file being read + * @fid: fid being read * @page: structure to page * */ - -static int v9fs_vfs_readpage(struct file *filp, struct page *page) +static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page) { int retval; loff_t offset; @@ -67,7 +67,7 @@ static int v9fs_vfs_readpage(struct file *filp, struct page *page) buffer = kmap(page); offset = page_offset(page); - retval = v9fs_file_readn(filp, buffer, NULL, PAGE_CACHE_SIZE, offset); + retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset); if (retval < 0) { v9fs_uncache_page(inode, page); goto done; @@ -86,6 +86,19 @@ done: return retval; } +/** + * v9fs_vfs_readpage - read an entire page in from 9P + * + * @filp: file being read + * @page: structure to page + * + */ + +static int v9fs_vfs_readpage(struct file *filp, struct page *page) +{ + return v9fs_fid_readpage(filp->private_data, page); +} + /** * v9fs_vfs_readpages - read a set of pages from 9P * @@ -124,7 +137,6 @@ static int v9fs_release_page(struct page *page, gfp_t gfp) { if (PagePrivate(page)) return 0; - return v9fs_fscache_release_page(page, gfp); } @@ -137,22 +149,87 @@ static int v9fs_release_page(struct page *page, gfp_t gfp) static void v9fs_invalidate_page(struct page *page, unsigned long offset) { + /* + * If called with zero offset, we should release + * the private state assocated with the page + */ if (offset == 0) v9fs_fscache_invalidate_page(page); } +static int v9fs_vfs_writepage_locked(struct page *page) +{ + char *buffer; + int retval, len; + loff_t offset, size; + mm_segment_t old_fs; + struct inode *inode = page->mapping->host; + + size = i_size_read(inode); + if (page->index == size >> PAGE_CACHE_SHIFT) + len = size & ~PAGE_CACHE_MASK; + else + len = PAGE_CACHE_SIZE; + + set_page_writeback(page); + + buffer = kmap(page); + offset = page_offset(page); + + old_fs = get_fs(); + set_fs(get_ds()); + /* We should have i_private always set */ + BUG_ON(!inode->i_private); + + retval = v9fs_file_write_internal(inode, + (struct p9_fid *)inode->i_private, + (__force const char __user *)buffer, + len, &offset, 0); + if (retval > 0) + retval = 0; + + set_fs(old_fs); + kunmap(page); + end_page_writeback(page); + return retval; +} + +static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) +{ + int retval; + + retval = v9fs_vfs_writepage_locked(page); + if (retval < 0) { + if (retval == -EAGAIN) { + redirty_page_for_writepage(wbc, page); + retval = 0; + } else { + SetPageError(page); + mapping_set_error(page->mapping, retval); + } + } else + retval = 0; + + unlock_page(page); + return retval; +} + /** * v9fs_launder_page - Writeback a dirty page - * Since the writes go directly to the server, we simply return a 0 - * here to indicate success. - * * Returns 0 on success. */ static int v9fs_launder_page(struct page *page) { + int retval; struct inode *inode = page->mapping->host; + v9fs_fscache_wait_on_page_write(inode, page); + if (clear_page_dirty_for_io(page)) { + retval = v9fs_vfs_writepage_locked(page); + if (retval) + return retval; + } return 0; } @@ -178,6 +255,11 @@ static int v9fs_launder_page(struct page *page) ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs) { + /* + * FIXME + * Now that we do caching with cache mode enabled, We need + * to support direct IO + */ P9_DPRINTK(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) " "off/no(%lld/%lu) EINVAL\n", iocb->ki_filp->f_path.dentry->d_name.name, @@ -185,11 +267,82 @@ ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, return -EINVAL; } + +static int v9fs_write_begin(struct file *filp, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata) +{ + int retval = 0; + struct page *page; + pgoff_t index = pos >> PAGE_CACHE_SHIFT; + struct inode *inode = mapping->host; + +start: + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) { + retval = -ENOMEM; + goto out; + } + BUG_ON(!inode->i_private); + if (PageUptodate(page)) + goto out; + + if (len == PAGE_CACHE_SIZE) + goto out; + + retval = v9fs_fid_readpage(inode->i_private, page); + page_cache_release(page); + if (!retval) + goto start; +out: + *pagep = page; + return retval; +} + +static int v9fs_write_end(struct file *filp, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + loff_t last_pos = pos + copied; + struct inode *inode = page->mapping->host; + + if (unlikely(copied < len)) { + /* + * zero out the rest of the area + */ + unsigned from = pos & (PAGE_CACHE_SIZE - 1); + + zero_user(page, from + copied, len - copied); + flush_dcache_page(page); + } + + if (!PageUptodate(page)) + SetPageUptodate(page); + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold the i_mutex. + */ + if (last_pos > inode->i_size) { + inode_add_bytes(inode, last_pos - inode->i_size); + i_size_write(inode, last_pos); + } + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + + return copied; +} + + const struct address_space_operations v9fs_addr_operations = { - .readpage = v9fs_vfs_readpage, - .readpages = v9fs_vfs_readpages, - .releasepage = v9fs_release_page, - .invalidatepage = v9fs_invalidate_page, - .launder_page = v9fs_launder_page, - .direct_IO = v9fs_direct_IO, + .readpage = v9fs_vfs_readpage, + .readpages = v9fs_vfs_readpages, + .set_page_dirty = __set_page_dirty_nobuffers, + .writepage = v9fs_vfs_writepage, + .write_begin = v9fs_write_begin, + .write_end = v9fs_write_end, + .releasepage = v9fs_release_page, + .invalidatepage = v9fs_invalidate_page, + .launder_page = v9fs_launder_page, + .direct_IO = v9fs_direct_IO, }; 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