[linux-cifs-client] Re: [PATCH] cifs: Convert cifs to new aops.
Steve French
smfrench at gmail.com
Wed Sep 24 19:34:44 GMT 2008
I have reviewed the patch and merged into cifs-2.6.git tree.
Will do some additional testing (with fsx and other test tools) while
at SDC plugfest this week.
On Wed, Sep 24, 2008 at 12:54 PM, Christoph Hellwig <hch at infradead.org> wrote:
> Might be worth Ccing Nick as he's started on finishing the last aops
> conversions again at Kernel Summit.
>
> On Wed, Sep 24, 2008 at 01:39:13PM -0400, Jeff Layton wrote:
>> This patch is based on the one originally posted by Nick Piggin. His
>> patch was very close, but had a couple of small bugs. Nick's original
>> comments follow:
>>
>> ---------------[snip]--------------
>>
>> This is another relatively naive conversion. Always do the read upfront
>> when the page is not uptodate (unless we're in the writethrough path).
>>
>> Fix an uninitialized data exposure where SetPageUptodate was called
>> before the page was uptodate.
>>
>> SetPageUptodate and switch to writeback mode in the case that the full
>> page was dirtied.
>>
>> Signed-off-by: Jeff Layton <jlayton at redhat.com>
>> Reviewed-by: Badari Pulavarty <pbadari at us.ibm.com>
>> Acked-by: Dave Kleikamp <shaggy at linux.vnet.ibm.com>
>> Cc: Steve French <smfrench at gmail.com>
>> Cc: Nick Piggin <npiggin at suse.de>
>> ---
>> fs/cifs/file.c | 120 +++++++++++++++++++++++++++----------------------------
>> 1 files changed, 59 insertions(+), 61 deletions(-)
>>
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index d39e852..c4a8a06 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -107,7 +107,7 @@ static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
>>
>> /* want handles we can use to read with first
>> in the list so we do not have to walk the
>> - list to search for one in prepare_write */
>> + list to search for one in write_begin */
>> if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
>> list_add_tail(&pCifsFile->flist,
>> &pCifsInode->openFileList);
>> @@ -915,7 +915,7 @@ ssize_t cifs_user_write(struct file *file, const char __user *write_data,
>> }
>>
>> static ssize_t cifs_write(struct file *file, const char *write_data,
>> - size_t write_size, loff_t *poffset)
>> + size_t write_size, loff_t *poffset)
>> {
>> int rc = 0;
>> unsigned int bytes_written = 0;
>> @@ -1455,49 +1455,52 @@ static int cifs_writepage(struct page *page, struct writeback_control *wbc)
>> return rc;
>> }
>>
>> -static int cifs_commit_write(struct file *file, struct page *page,
>> - unsigned offset, unsigned to)
>> +static int cifs_write_end(struct file *file, struct address_space *mapping,
>> + loff_t pos, unsigned len, unsigned copied,
>> + struct page *page, void *fsdata)
>> {
>> - int xid;
>> - int rc = 0;
>> - struct inode *inode = page->mapping->host;
>> - loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
>> - char *page_data;
>> + int rc;
>> + struct inode *inode = mapping->host;
>>
>> - xid = GetXid();
>> - cFYI(1, ("commit write for page %p up to position %lld for %d",
>> - page, position, to));
>> - spin_lock(&inode->i_lock);
>> - if (position > inode->i_size)
>> - i_size_write(inode, position);
>> + cFYI(1, ("write_end for page %p from pos %lld with %d bytes",
>> + page, pos, copied));
>> +
>> + if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
>> + SetPageUptodate(page);
>>
>> - spin_unlock(&inode->i_lock);
>> if (!PageUptodate(page)) {
>> - position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
>> - /* can not rely on (or let) writepage write this data */
>> - if (to < offset) {
>> - cFYI(1, ("Illegal offsets, can not copy from %d to %d",
>> - offset, to));
>> - FreeXid(xid);
>> - return rc;
>> - }
>> + char *page_data;
>> + unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
>> + int xid;
>> +
>> + xid = GetXid();
>> /* this is probably better than directly calling
>> partialpage_write since in this function the file handle is
>> known which we might as well leverage */
>> /* BB check if anything else missing out of ppw
>> such as updating last write time */
>> page_data = kmap(page);
>> - rc = cifs_write(file, page_data + offset, to-offset,
>> - &position);
>> - if (rc > 0)
>> - rc = 0;
>> - /* else if (rc < 0) should we set writebehind rc? */
>> + rc = cifs_write(file, page_data + offset, copied, &pos);
>> + /* if (rc < 0) should we set writebehind rc? */
>> kunmap(page);
>> +
>> + FreeXid(xid);
>> } else {
>> + rc = copied;
>> + pos += copied;
>> set_page_dirty(page);
>> }
>>
>> - FreeXid(xid);
>> + if (rc > 0) {
>> + spin_lock(&inode->i_lock);
>> + if (pos > inode->i_size)
>> + i_size_write(inode, pos);
>> + spin_unlock(&inode->i_lock);
>> + }
>> +
>> + unlock_page(page);
>> + page_cache_release(page);
>> +
>> return rc;
>> }
>>
>> @@ -2043,49 +2046,44 @@ bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
>> return true;
>> }
>>
>> -static int cifs_prepare_write(struct file *file, struct page *page,
>> - unsigned from, unsigned to)
>> +static int cifs_write_begin(struct file *file, struct address_space *mapping,
>> + loff_t pos, unsigned len, unsigned flags,
>> + struct page **pagep, void **fsdata)
>> {
>> - int rc = 0;
>> - loff_t i_size;
>> - loff_t offset;
>> + pgoff_t index = pos >> PAGE_CACHE_SHIFT;
>> + loff_t offset = pos & (PAGE_CACHE_SIZE - 1);
>> +
>> + cFYI(1, ("write_begin from %lld len %d", (long long)pos, len));
>> +
>> + *pagep = __grab_cache_page(mapping, index);
>> + if (!*pagep)
>> + return -ENOMEM;
>>
>> - cFYI(1, ("prepare write for page %p from %d to %d", page, from, to));
>> - if (PageUptodate(page))
>> + if (PageUptodate(*pagep))
>> return 0;
>>
>> /* If we are writing a full page it will be up to date,
>> no need to read from the server */
>> - if ((to == PAGE_CACHE_SIZE) && (from == 0)) {
>> - SetPageUptodate(page);
>> + if (len == PAGE_CACHE_SIZE && flags & AOP_FLAG_UNINTERRUPTIBLE)
>> return 0;
>> - }
>>
>> - offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
>> - i_size = i_size_read(page->mapping->host);
>> + if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
>> + int rc;
>>
>> - if ((offset >= i_size) ||
>> - ((from == 0) && (offset + to) >= i_size)) {
>> - /*
>> - * We don't need to read data beyond the end of the file.
>> - * zero it, and set the page uptodate
>> - */
>> - simple_prepare_write(file, page, from, to);
>> - SetPageUptodate(page);
>> - } else if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
>> /* might as well read a page, it is fast enough */
>> - rc = cifs_readpage_worker(file, page, &offset);
>> + rc = cifs_readpage_worker(file, *pagep, &offset);
>> +
>> + /* we do not need to pass errors back
>> + e.g. if we do not have read access to the file
>> + because cifs_write_end will attempt synchronous writes
>> + -- shaggy */
>> } else {
>> /* we could try using another file handle if there is one -
>> but how would we lock it to prevent close of that handle
>> racing with this read? In any case
>> - this will be written out by commit_write so is fine */
>> + this will be written out by write_end so is fine */
>> }
>>
>> - /* we do not need to pass errors back
>> - e.g. if we do not have read access to the file
>> - because cifs_commit_write will do the right thing. -- shaggy */
>> -
>> return 0;
>> }
>>
>> @@ -2094,8 +2092,8 @@ const struct address_space_operations cifs_addr_ops = {
>> .readpages = cifs_readpages,
>> .writepage = cifs_writepage,
>> .writepages = cifs_writepages,
>> - .prepare_write = cifs_prepare_write,
>> - .commit_write = cifs_commit_write,
>> + .write_begin = cifs_write_begin,
>> + .write_end = cifs_write_end,
>> .set_page_dirty = __set_page_dirty_nobuffers,
>> /* .sync_page = cifs_sync_page, */
>> /* .direct_IO = */
>> @@ -2110,8 +2108,8 @@ const struct address_space_operations cifs_addr_ops_smallbuf = {
>> .readpage = cifs_readpage,
>> .writepage = cifs_writepage,
>> .writepages = cifs_writepages,
>> - .prepare_write = cifs_prepare_write,
>> - .commit_write = cifs_commit_write,
>> + .write_begin = cifs_write_begin,
>> + .write_end = cifs_write_end,
>> .set_page_dirty = __set_page_dirty_nobuffers,
>> /* .sync_page = cifs_sync_page, */
>> /* .direct_IO = */
>> --
>> 1.5.5.1
>>
>> --
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> ---end quoted text---
>
--
Thanks,
Steve
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