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author | Pavel Shilovsky <piastryyy@gmail.com> | 2011-01-24 14:16:35 -0500 |
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committer | Steve French <sfrench@us.ibm.com> | 2011-01-25 19:30:13 +0000 |
commit | 72432ffcf555decbbae47f1be338e1d2f210aa69 (patch) | |
tree | 4293cb6e5b880071099756b7523f8f36bb7e16cc /fs/cifs/file.c | |
parent | 93c100c0b423266c0ee28497e90fdf27c05e6b8e (diff) | |
download | lwn-72432ffcf555decbbae47f1be338e1d2f210aa69.tar.gz lwn-72432ffcf555decbbae47f1be338e1d2f210aa69.zip |
CIFS: Implement cifs_strict_writev (try #4)
If we don't have Exclusive oplock we write a data to the server.
Also set invalidate_mapping flag on the inode if we wrote something
to the server. Add cifs_iovec_write to let the client write iovec
buffers through CIFSSMBWrite2.
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/cifs/file.c')
-rw-r--r-- | fs/cifs/file.c | 202 |
1 files changed, 201 insertions, 1 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index d7d65a70678e..0de17c1db608 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -848,7 +848,7 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock) } /* update the file size (if needed) after a write */ -static void +void cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset, unsigned int bytes_written) { @@ -1619,6 +1619,206 @@ int cifs_flush(struct file *file, fl_owner_t id) return rc; } +static int +cifs_write_allocate_pages(struct page **pages, unsigned long num_pages) +{ + int rc = 0; + unsigned long i; + + for (i = 0; i < num_pages; i++) { + pages[i] = alloc_page(__GFP_HIGHMEM); + if (!pages[i]) { + /* + * save number of pages we have already allocated and + * return with ENOMEM error + */ + num_pages = i; + rc = -ENOMEM; + goto error; + } + } + + return rc; + +error: + for (i = 0; i < num_pages; i++) + put_page(pages[i]); + return rc; +} + +static inline +size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len) +{ + size_t num_pages; + size_t clen; + + clen = min_t(const size_t, len, wsize); + num_pages = clen / PAGE_CACHE_SIZE; + if (clen % PAGE_CACHE_SIZE) + num_pages++; + + if (cur_len) + *cur_len = clen; + + return num_pages; +} + +static ssize_t +cifs_iovec_write(struct file *file, const struct iovec *iov, + unsigned long nr_segs, loff_t *poffset) +{ + size_t total_written = 0, written = 0; + unsigned long num_pages, npages; + size_t copied, len, cur_len, i; + struct kvec *to_send; + struct page **pages; + struct iov_iter it; + struct inode *inode; + struct cifsFileInfo *open_file; + struct cifsTconInfo *pTcon; + struct cifs_sb_info *cifs_sb; + int xid, rc; + + len = iov_length(iov, nr_segs); + if (!len) + return 0; + + rc = generic_write_checks(file, poffset, &len, 0); + if (rc) + return rc; + + cifs_sb = CIFS_SB(file->f_path.dentry->d_sb); + num_pages = get_numpages(cifs_sb->wsize, len, &cur_len); + + pages = kmalloc(sizeof(struct pages *)*num_pages, GFP_KERNEL); + if (!pages) + return -ENOMEM; + + to_send = kmalloc(sizeof(struct kvec)*(num_pages + 1), GFP_KERNEL); + if (!to_send) { + kfree(pages); + return -ENOMEM; + } + + rc = cifs_write_allocate_pages(pages, num_pages); + if (rc) { + kfree(pages); + kfree(to_send); + return rc; + } + + xid = GetXid(); + open_file = file->private_data; + pTcon = tlink_tcon(open_file->tlink); + inode = file->f_path.dentry->d_inode; + + iov_iter_init(&it, iov, nr_segs, len, 0); + npages = num_pages; + + do { + size_t save_len = cur_len; + for (i = 0; i < npages; i++) { + copied = min_t(const size_t, cur_len, PAGE_CACHE_SIZE); + copied = iov_iter_copy_from_user(pages[i], &it, 0, + copied); + cur_len -= copied; + iov_iter_advance(&it, copied); + to_send[i+1].iov_base = kmap(pages[i]); + to_send[i+1].iov_len = copied; + } + + cur_len = save_len - cur_len; + + do { + if (open_file->invalidHandle) { + rc = cifs_reopen_file(open_file, false); + if (rc != 0) + break; + } + rc = CIFSSMBWrite2(xid, pTcon, open_file->netfid, + cur_len, *poffset, &written, + to_send, npages, 0); + } while (rc == -EAGAIN); + + for (i = 0; i < npages; i++) + kunmap(pages[i]); + + if (written) { + len -= written; + total_written += written; + cifs_update_eof(CIFS_I(inode), *poffset, written); + *poffset += written; + } else if (rc < 0) { + if (!total_written) + total_written = rc; + break; + } + + /* get length and number of kvecs of the next write */ + npages = get_numpages(cifs_sb->wsize, len, &cur_len); + } while (len > 0); + + if (total_written > 0) { + spin_lock(&inode->i_lock); + if (*poffset > inode->i_size) + i_size_write(inode, *poffset); + spin_unlock(&inode->i_lock); + } + + cifs_stats_bytes_written(pTcon, total_written); + mark_inode_dirty_sync(inode); + + for (i = 0; i < num_pages; i++) + put_page(pages[i]); + kfree(to_send); + kfree(pages); + FreeXid(xid); + return total_written; +} + +static ssize_t cifs_user_writev(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + ssize_t written; + struct inode *inode; + + inode = iocb->ki_filp->f_path.dentry->d_inode; + + /* + * BB - optimize the way when signing is disabled. We can drop this + * extra memory-to-memory copying and use iovec buffers for constructing + * write request. + */ + + written = cifs_iovec_write(iocb->ki_filp, iov, nr_segs, &pos); + if (written > 0) { + CIFS_I(inode)->invalid_mapping = true; + iocb->ki_pos = pos; + } + + return written; +} + +ssize_t cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct inode *inode; + + inode = iocb->ki_filp->f_path.dentry->d_inode; + + if (CIFS_I(inode)->clientCanCacheAll) + return generic_file_aio_write(iocb, iov, nr_segs, pos); + + /* + * In strict cache mode we need to write the data to the server exactly + * from the pos to pos+len-1 rather than flush all affected pages + * because it may cause a error with mandatory locks on these pages but + * not on the region from pos to ppos+len-1. + */ + + return cifs_user_writev(iocb, iov, nr_segs, pos); +} + static ssize_t cifs_iovec_read(struct file *file, const struct iovec *iov, unsigned long nr_segs, loff_t *poffset) |