ocfs2: shared writeable mmap
Implement cluster consistent shared writeable mappings using the ->page_mkwrite() callback. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
This commit is contained in:
Mark Fasheh
Родитель
607d44aa3f
Коммит
7307de8051
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@ -1034,7 +1034,8 @@ out:
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*/
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static int ocfs2_grab_pages_for_write(struct address_space *mapping,
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struct ocfs2_write_ctxt *wc,
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u32 cpos, loff_t user_pos, int new)
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u32 cpos, loff_t user_pos, int new,
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struct page *mmap_page)
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{
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int ret = 0, i;
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unsigned long start, target_index, index;
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@ -1058,11 +1059,36 @@ static int ocfs2_grab_pages_for_write(struct address_space *mapping,
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for(i = 0; i < wc->w_num_pages; i++) {
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index = start + i;
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wc->w_pages[i] = find_or_create_page(mapping, index, GFP_NOFS);
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if (!wc->w_pages[i]) {
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ret = -ENOMEM;
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mlog_errno(ret);
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goto out;
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if (index == target_index && mmap_page) {
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/*
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* ocfs2_pagemkwrite() is a little different
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* and wants us to directly use the page
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* passed in.
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*/
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lock_page(mmap_page);
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if (mmap_page->mapping != mapping) {
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unlock_page(mmap_page);
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/*
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* Sanity check - the locking in
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* ocfs2_pagemkwrite() should ensure
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* that this code doesn't trigger.
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*/
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ret = -EINVAL;
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mlog_errno(ret);
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goto out;
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}
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page_cache_get(mmap_page);
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wc->w_pages[i] = mmap_page;
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} else {
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wc->w_pages[i] = find_or_create_page(mapping, index,
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GFP_NOFS);
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if (!wc->w_pages[i]) {
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ret = -ENOMEM;
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mlog_errno(ret);
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goto out;
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}
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}
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if (index == target_index)
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@ -1213,10 +1239,10 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
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}
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}
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static int ocfs2_write_begin_nolock(struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata,
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struct buffer_head *di_bh)
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int ocfs2_write_begin_nolock(struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata,
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struct buffer_head *di_bh, struct page *mmap_page)
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{
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int ret, i, credits = OCFS2_INODE_UPDATE_CREDITS;
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unsigned int num_clusters = 0, clusters_to_alloc = 0;
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@ -1318,7 +1344,7 @@ static int ocfs2_write_begin_nolock(struct address_space *mapping,
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* extent.
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*/
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ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos,
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clusters_to_alloc);
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clusters_to_alloc, mmap_page);
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if (ret) {
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mlog_errno(ret);
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goto out_commit;
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@ -1386,7 +1412,7 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping,
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}
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ret = ocfs2_write_begin_nolock(mapping, pos, len, flags, pagep,
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fsdata, di_bh);
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fsdata, di_bh, NULL);
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if (ret) {
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mlog_errno(ret);
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goto out_fail_data;
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@ -1407,9 +1433,9 @@ out_fail:
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return ret;
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}
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static int ocfs2_write_end_nolock(struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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int ocfs2_write_end_nolock(struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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int i;
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unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
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@ -50,6 +50,15 @@ int ocfs2_write_end(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata);
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int ocfs2_write_end_nolock(struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata);
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int ocfs2_write_begin_nolock(struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata,
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struct buffer_head *di_bh, struct page *mmap_page);
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/* all ocfs2_dio_end_io()'s fault */
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#define ocfs2_iocb_is_rw_locked(iocb) \
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test_bit(0, (unsigned long *)&iocb->private)
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@ -1001,6 +1001,13 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
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goto bail_unlock;
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}
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/*
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* This will intentionally not wind up calling vmtruncate(),
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* since all the work for a size change has been done above.
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* Otherwise, we could get into problems with truncate as
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* ip_alloc_sem is used there to protect against i_size
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* changes.
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*/
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status = inode_setattr(inode, attr);
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if (status < 0) {
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mlog_errno(status);
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167
fs/ocfs2/mmap.c
167
fs/ocfs2/mmap.c
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@ -37,11 +37,29 @@
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#include "ocfs2.h"
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#include "aops.h"
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#include "dlmglue.h"
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#include "file.h"
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#include "inode.h"
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#include "mmap.h"
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static inline int ocfs2_vm_op_block_sigs(sigset_t *blocked, sigset_t *oldset)
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{
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/* The best way to deal with signals in the vm path is
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* to block them upfront, rather than allowing the
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* locking paths to return -ERESTARTSYS. */
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sigfillset(blocked);
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/* We should technically never get a bad return value
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* from sigprocmask */
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return sigprocmask(SIG_BLOCK, blocked, oldset);
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}
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static inline int ocfs2_vm_op_unblock_sigs(sigset_t *oldset)
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{
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return sigprocmask(SIG_SETMASK, oldset, NULL);
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}
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static struct page *ocfs2_nopage(struct vm_area_struct * area,
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unsigned long address,
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int *type)
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@ -53,14 +71,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area,
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mlog_entry("(area=%p, address=%lu, type=%p)\n", area, address,
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type);
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/* The best way to deal with signals in this path is
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* to block them upfront, rather than allowing the
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* locking paths to return -ERESTARTSYS. */
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sigfillset(&blocked);
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/* We should technically never get a bad ret return
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* from sigprocmask */
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ret = sigprocmask(SIG_BLOCK, &blocked, &oldset);
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ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
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if (ret < 0) {
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mlog_errno(ret);
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goto out;
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@ -68,7 +79,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area,
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page = filemap_nopage(area, address, type);
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ret = sigprocmask(SIG_SETMASK, &oldset, NULL);
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ret = ocfs2_vm_op_unblock_sigs(&oldset);
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if (ret < 0)
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mlog_errno(ret);
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out:
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@ -76,27 +87,135 @@ out:
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return page;
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}
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static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
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struct page *page)
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{
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int ret;
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struct address_space *mapping = inode->i_mapping;
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loff_t pos = page->index << PAGE_CACHE_SHIFT;
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unsigned int len = PAGE_CACHE_SIZE;
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pgoff_t last_index;
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struct page *locked_page = NULL;
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void *fsdata;
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loff_t size = i_size_read(inode);
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/*
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* Another node might have truncated while we were waiting on
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* cluster locks.
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*/
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last_index = size >> PAGE_CACHE_SHIFT;
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if (page->index > last_index) {
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ret = -EINVAL;
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goto out;
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}
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/*
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* The i_size check above doesn't catch the case where nodes
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* truncated and then re-extended the file. We'll re-check the
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* page mapping after taking the page lock inside of
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* ocfs2_write_begin_nolock().
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*/
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if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
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ret = -EINVAL;
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goto out;
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}
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/*
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* Call ocfs2_write_begin() and ocfs2_write_end() to take
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* advantage of the allocation code there. We pass a write
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* length of the whole page (chopped to i_size) to make sure
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* the whole thing is allocated.
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*
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* Since we know the page is up to date, we don't have to
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* worry about ocfs2_write_begin() skipping some buffer reads
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* because the "write" would invalidate their data.
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*/
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if (page->index == last_index)
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len = size & ~PAGE_CACHE_MASK;
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ret = ocfs2_write_begin_nolock(mapping, pos, len, 0, &locked_page,
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&fsdata, di_bh, page);
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if (ret) {
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if (ret != -ENOSPC)
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mlog_errno(ret);
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goto out;
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}
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ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
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fsdata);
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if (ret < 0) {
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mlog_errno(ret);
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goto out;
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}
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BUG_ON(ret != len);
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ret = 0;
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out:
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return ret;
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}
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static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct page *page)
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{
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struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
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struct buffer_head *di_bh = NULL;
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sigset_t blocked, oldset;
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int ret, ret2;
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ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
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if (ret < 0) {
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mlog_errno(ret);
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return ret;
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}
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/*
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* The cluster locks taken will block a truncate from another
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* node. Taking the data lock will also ensure that we don't
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* attempt page truncation as part of a downconvert.
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*/
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ret = ocfs2_meta_lock(inode, &di_bh, 1);
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if (ret < 0) {
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mlog_errno(ret);
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goto out;
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}
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/*
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* The alloc sem should be enough to serialize with
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* ocfs2_truncate_file() changing i_size as well as any thread
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* modifying the inode btree.
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*/
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down_write(&OCFS2_I(inode)->ip_alloc_sem);
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ret = ocfs2_data_lock(inode, 1);
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if (ret < 0) {
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mlog_errno(ret);
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goto out_meta_unlock;
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}
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ret = __ocfs2_page_mkwrite(inode, di_bh, page);
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ocfs2_data_unlock(inode, 1);
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out_meta_unlock:
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up_write(&OCFS2_I(inode)->ip_alloc_sem);
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brelse(di_bh);
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ocfs2_meta_unlock(inode, 1);
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out:
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ret2 = ocfs2_vm_op_unblock_sigs(&oldset);
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if (ret2 < 0)
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mlog_errno(ret2);
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return ret;
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}
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static struct vm_operations_struct ocfs2_file_vm_ops = {
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.nopage = ocfs2_nopage,
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.nopage = ocfs2_nopage,
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.page_mkwrite = ocfs2_page_mkwrite,
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};
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int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
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{
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int ret = 0, lock_level = 0;
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struct ocfs2_super *osb = OCFS2_SB(file->f_dentry->d_inode->i_sb);
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/*
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* Only support shared writeable mmap for local mounts which
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* don't know about holes.
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*/
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if ((!ocfs2_mount_local(osb) || ocfs2_sparse_alloc(osb)) &&
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((vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_MAYSHARE)) &&
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((vma->vm_flags & VM_WRITE) || (vma->vm_flags & VM_MAYWRITE))) {
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mlog(0, "disallow shared writable mmaps %lx\n", vma->vm_flags);
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/* This is -EINVAL because generic_file_readonly_mmap
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* returns it in a similar situation. */
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return -EINVAL;
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}
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ret = ocfs2_meta_lock_atime(file->f_dentry->d_inode,
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file->f_vfsmnt, &lock_level);
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