#include <linux/ceph/ceph_debug.h>
#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h> /* generic_writepages */
#include <linux/slab.h>
#include <linux/pagevec.h>
#include <linux/task_io_accounting_ops.h>
#include "super.h"
#include "mds_client.h"
#include <linux/ceph/osd_client.h>
/*
* Ceph address space ops.
*
* There are a few funny things going on here.
*
* The page->private field is used to reference a struct
* ceph_snap_context for _every_ dirty page. This indicates which
* snapshot the page was logically dirtied in, and thus which snap
* context needs to be associated with the osd write during writeback.
*
* Similarly, struct ceph_inode_info maintains a set of counters to
* count dirty pages on the inode. In the absence of snapshots,
* i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
*
* When a snapshot is taken (that is, when the client receives
* notification that a snapshot was taken), each inode with caps and
* with dirty pages (dirty pages implies there is a cap) gets a new
* ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
* order, new snaps go to the tail). The i_wrbuffer_ref_head count is
* moved to capsnap->dirty. (Unless a sync write is currently in
* progress. In that case, the capsnap is said to be "pending", new
* writes cannot start, and the capsnap isn't "finalized" until the
* write completes (or fails) and a final size/mtime for the inode for
* that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0.
*
* On writeback, we must submit writes to the osd IN SNAP ORDER. So,
* we look for the first capsnap in i_cap_snaps and write out pages in
* that snap context _only_. Then we move on to the next capsnap,
* eventually reaching the "live" or "head" context (i.e., pages that
* are not yet snapped) and are writing the most recently dirtied
* pages.
*
* Invalidate and so forth must take care to ensure the dirty page
* accounting is preserved.
*/
#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
#define CONGESTION_OFF_THRESH(congestion_kb) \
(CONGESTION_ON_THRESH(congestion_kb) - \
(CONGESTION_ON_THRESH(congestion_kb) >> 2))
/*
* Dirty a page. Optimistically adjust accounting, on the assumption
* that we won't race with invalidate. If we do, readjust.
*/
static int ceph_set_page_dirty(struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode;
struct ceph_inode_info *ci;
int undo = 0;
struct ceph_snap_context *snapc;
if (unlikely(!mapping))
return !TestSetPageDirty(page);
if (TestSetPageDirty(page)) {
dout("%p set_page_dirty %p idx %lu -- already dirty\n",
mapping->host, page, page->index);
return 0;
}
inode = mapping->host;
ci = ceph_inode(inode);
/*
* Note that we're grabbing a snapc ref here without holding
* any locks!
*/
snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
/* dirty the head */
spin_lock(&inode->i_lock);
if (ci->i_head_snapc == NULL)
ci->i_head_snapc = ceph_get_snap_context(snapc);
++ci->i_wrbuffer_ref_head;
if (ci->i_wrbuffer_ref == 0)
ihold(inode);
++ci->i_wrbuffer_ref;
dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
"snapc %p seq %lld (%d snaps)\n",
mapping->host, page, page->index,
ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
snapc, snapc->seq, snapc->num_snaps);
spin_unlock(&inode->i_lock);
/* now adjust page */
spin_lock_irq(&mapping->tree_lock);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(!PageUptodate(page));
account_page_dirtied(page, page->mapping);
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
/*
* Reference snap context in page->private. Also set
* PagePrivate so that we get invalidatepage callback.
*/
page->private = (unsigned long)snapc;
SetPagePrivate(page);
} else {
dout("ANON set_page_dirty %p (raced truncate?)\n", page);
undo = 1;
}
spin_unlock_irq(&mapping->tree_lock);
if (undo)
/* whoops, we failed to dirty the page */
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
BUG_ON(!PageDirty(page));
return 1;
}
/*
* If we are truncating the full page (i.e. offset == 0), adjust the
* dirty page counters appropriately. Only called if there is private
* data on the page.
*/
static void ceph_invalidatepage(struct page *page, unsigned long offset)
{
struct inode *inode;
struct ceph_inode_info *ci;
struct ceph_snap_context *snapc = (void *)page->private;
BUG_ON(!PageLocked(page));
BUG_ON(!page->private);
BUG_ON(!PagePrivate(page));
BUG_ON(!page->mapping);
inode = page->mapping->host;
/*
* We can get non-dirty pages here due to races between
* set_page_dirty and truncate_complete_page; just spit out a
* warning, in case we end up with accounting problems later.
*/
if (!PageDirty(page))
pr_err("%p invalidatepage %p page not dirty\n", inode, page);
if (offset == 0)
ClearPageChecked(page);
ci = ceph_inode(inode);
if (offset == 0) {
dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
inode, page, page->index, offset);
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
ceph_put_snap_context(snapc);
page->private = 0;
ClearPagePrivate(page);
} else {
dout("%p invalidatepage %p idx %lu partial dirty page\n",
inode, page, page->index);
}
}
/* just a sanity check */
static int ceph_releasepage(struct page *page, gfp_t g)
{
struct inode *inode = page->mapping ? page->mapping->host : NULL;
dout("%p releasepage %p idx %lu\n", inode, page, page->index);
WARN_ON(PageDirty(page));
WARN_ON(page->private);
WARN_ON(PagePrivate(page));
return 0;
}
/*
* read a single page, without unlocking it.
*/
static int readpage_nounlock(struct file *filp, struct page *page)
{
struct inode *inode = filp->f_dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_osd_client *osdc =
&ceph_inode_to_client(inode)->client->osdc;
int err = 0;
u64 len = PAGE_CACHE_SIZE;
dout("readpage inode %p file %p page %p index %lu\n",
inode, filp, page, page->index);
err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
page->index << PAGE_CACHE_SHIFT, &len,
ci->i_truncate_seq, ci->i_truncate_size,
&page, 1, 0);
if (err == -ENOENT)
err = 0;
if (err < 0) {
SetPageError(page);
goto out;
} else if (err < PAGE_CACHE_SIZE) {
/* zero fill remainder of page */
zero_user_segment(page, err, PAGE_CACHE_SIZE);
}
SetPageUptodate(page);
out:
return err < 0 ? err : 0;
}
static int ceph_readpage(struct file *filp, struct page *page)
{
int r = readpage_nounlock(filp, page);
unlock_page(page);
return r;
}
/*
* Build a vector of contiguous pages from the provided page list.
*/
static struct page **page_vector_from_list(struct list_head *page_list,
unsigned *nr_pages)
{
struct page **pages;
struct page *page;
int next_index, contig_pages = 0;
/* build page vector */
pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
if (!pages)
return ERR_PTR(-ENOMEM);
BUG_ON(list_empty(page_list));
next_index = list_entry(page_list->prev, struct page, lru)->index;
list_for_each_entry_reverse(page, page_list, lru) {
if (page->index == next_index) {
dout("readpages page %d %p\n", contig_pages, page);
pages[contig_pages] = page;
contig_pages++;
next_index++;
} else {
break;
}
}
*nr_pages = contig_pages;
return pages;
}
/*
* Read multiple pages. Leave pages we don't read + unlock in page_list;
* the caller (VM) cleans them up.
*/
static int ceph_readpages(struct file *file, struct address_space *mapping,
struct list_head *page_list, unsigned nr_pages)
{
struct inode *inode = file->f_dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_osd_client *osdc =
&ceph_inode_to_client(inode)->client->osdc;
int rc = 0;
struct page **pages;
loff_t offset;
u64 len;
dout("readpages %p file %p nr_pages %d\n",
inode, file, nr_pages);
pages = page_vector_from_list(page_list, &nr_pages);
if (IS_ERR(pages))
return PTR_ERR(pages);
/* guess read extent */
offset = pages[0]->index << PAGE_CACHE_SHIFT;
len = nr_pages << PAGE_CACHE_SHIFT;
rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
offset, &len,
ci->i_truncate_seq, ci->i_truncate_size,
pages, nr_pages, 0);
if (rc == -ENOENT)
rc = 0;
if (rc < 0)
goto out;
for (; !list_empty(page_list) && len > 0;
rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
struct page *page =
list_entry(page_list->prev, struct page, lru);
list_del(&page->lru);
if (rc < (int)PAGE_CACHE_SIZE) {
/* zero (remainder of) page */
int s = rc < 0 ? 0 : rc;
zero_user_segment(page, s, PAGE_CACHE_SIZE);
}
if (add_to_page_cache_lru(page, mapping, page->index,
GFP_NOFS)) {
page_cache_release(page);
dout("readpages %p add_to_page_cache failed %p\n",
inode, page);
continue;
}
dout("readpages %p adding %p idx %lu\n", inode, page,
page->index);
flush_dcache_page(page);
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
}
rc = 0;
out:
kfree(pages);
return rc;
}
/*
* Get ref for the oldest snapc for an inode with dirty data... that is, the
* only snap context we are allowed to write back.
*/
static struct ceph_snap_context *get_oldest_context(struct inode *inode,
u64 *snap_size)
{
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_snap_context *snapc = NULL;
struct ceph_cap_snap *capsnap = NULL;
spin_lock(&inode->i_lock);
list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
capsnap->context, capsnap->dirty_pages);
if (capsnap->dirty_pages) {
snapc = ceph_get_snap_context(capsnap->context);
if (snap_size)
*snap_size = capsnap->size;
break;
}
}
if (!snapc && ci->i_wrbuffer_ref_head) {
snapc = ceph_get_snap_context(ci->i_head_snapc);
dout(" head snapc %p has %d dirty pages\n",
snapc, ci->i_wrbuffer_ref_head);
}
spin_unlock(&inode->i_lock);
return snapc;
}
/*
* Write a single page, but leave the page locked.
*
* If we get a write error, set the page error bit, but still adjust the
* dirty page accounting (i.e., page is no longer dirty).
*/
static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
{
struct inode *inode;
struct ceph_inode_info *ci;
struct ceph_fs_client *fsc;
struct ceph_osd_client *osdc;
loff_t page_off = page->index << PAGE_CACHE_SHIFT;
int len = PAGE_CACHE_SIZE;
loff_t i_size;
int err = 0;
struct ceph_snap_context *snapc, *oldest;
u64 snap_size = 0;
long writeback_stat;
dout("writepage %p idx %lu\n", page, page->index);
if (!page->mapping || !page->mapping->host) {
dout("writepage %p - no mapping\n", page);
return -EFAULT;
}
inode = page->mapping->host;
ci = ceph_inode(inode);
fsc = ceph_inode_to_client(inode);
osdc = &fsc->client->osdc;
/* verify this is a writeable snap context */
snapc = (void *)page->private;
if (snapc == NULL) {
dout("writepage %p page %p not dirty?\n", inode, page);
goto out;
}
oldest = get_oldest_context(inode, &snap_size);
if (snapc->seq > oldest->seq) {
dout("writepage %p page %p snapc %p not writeable - noop\n",
inode, page, (void *)page->private);
/* we should only noop if called by kswapd */
WARN_ON((current->flags & PF_MEMALLOC) == 0);
ceph_put_snap_context(oldest);
goto out;
}
ceph_put_snap_context(oldest);
/* is this a partial page at end of file? */
if (snap_size)
i_size = snap_size;
else
i_size = i_size_read(inode);
if (i_size < page_off + len)
len = i_size - page_off;
dout("writepage %p page %p index %lu on %llu~%u snapc %p\n",
inode, page, page->index, page_off, len, snapc);
writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
if (writeback_stat >
CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
set_page_writeback(page);
err = ceph_osdc_writepages(osdc, ceph_vino(inode),
&ci->i_layout, snapc,
page_off, len,
ci->i_truncate_seq, ci->i_truncate_size,
&inode->i_mtime,
&page, 1, 0, 0, true);
if (err < 0) {
dout("writepage setting page/mapping error %d %p\n", err, page);
SetPageError(page);
mapping_set_error(&inode->i_data, err);
if (wbc)
wbc->pages_skipped++;
} else {
dout("writepage cleaned page %p\n", page);
err = 0; /* vfs expects us to return 0 */
}
page->private = 0;
ClearPagePrivate(page);
end_page_writeback(page);
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
ceph_put_snap_context(snapc); /* page's reference */
out:
return err;
}
static int ceph_writepage(struct page *page, struct writeback_control *wbc)
{
int err;
struct inode *inode = page->mapping->host;
BUG_ON(!inode);
igrab(inode);
err = writepage_nounlock(page, wbc);
unlock_page(page);
iput(inode);
return err;
}
/*
* lame release_pages helper. release_pages() isn't exported to
* modules.
*/
static void ceph_release_pages(struct page **pages, int num)
{
struct pagevec pvec;
int i;
pagevec_init(&pvec, 0);
for (i = 0; i < num; i++) {
if (pagevec_add(&pvec, pages[i]) == 0)
pagevec_release(&pvec);
}
pagevec_release(&pvec);
}
/*
* async writeback completion handler.
*
* If we get an error, set the mapping error bit, but not the individual
* page error bits.
*/
static void writepages_finish(struct ceph_osd_request *req,
struct ceph_msg *msg)
{
struct inode *inode = req->r_inode;
struct ceph_osd_reply_head *replyhead;
struct ceph_osd_op *op;
struct ceph_inode_info *ci = ceph_inode(inode);
unsigned wrote;
struct page *page;
int i;
struct ceph_snap_context *snapc = req->r_snapc;
struct address_space *mapping = inode->i_mapping;
__s32 rc = -EIO;
u64 bytes = 0;
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
long writeback_stat;
unsigned issued = ceph_caps_issued(ci);
/* parse reply */
replyhead = msg->front.iov_base;
WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
op = (void *)(replyhead + 1);
rc = le32_to_cpu(replyhead->result);
bytes = le64_to_cpu(op->extent.length);
if (rc >= 0) {
/*
* Assume we wrote the pages we originally sent. The
* osd might reply with fewer pages if our writeback
* raced with a truncation and was adjusted at the osd,
* so don't believe the reply.
*/
wrote = req->r_num_pages;
} else {
wrote = 0;
mapping_set_error(mapping, rc);
}
dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
inode, rc, bytes, wrote);
/* clean all pages */
for (i = 0; i < req->r_num_pages; i++) {
page = req->r_pages[i];
BUG_ON(!page);
WARN_ON(!PageUptodate(page));
writeback_stat =
atomic_long_dec_return(&fsc->writeback_count);
if (writeback_stat <
CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
clear_bdi_congested(&fsc->backing_dev_info,
BLK_RW_ASYNC);
ceph_put_snap_context((void *)page->private);
page->private = 0;
ClearPagePrivate(page);
dout("unlocking %d %p\n", i, page);
end_page_writeback(page);
/*
* We lost the cache cap, need to truncate the page before
* it is unlocked, otherwise we'd truncate it later in the
* page truncation thread, possibly losing some data that
* raced its way in
*/
if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
generic_error_remove_page(inode->i_mapping, page);
unlock_page(page);
}
dout("%p wrote+cleaned %d pages\n", inode, wrote);
ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
ceph_release_pages(req->r_pages, req->r_num_pages);
if (req->r_pages_from_pool)
mempool_free(req->r_pages,
ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
else
kfree(req->r_pages);
ceph_osdc_put_request(req);
}
/*
* allocate a page vec, either directly, or if necessary, via a the
* mempool. we avoid the mempool if we can because req->r_num_pages
* may be less than the maximum write size.
*/
static void alloc_page_vec(struct ceph_fs_client *fsc,
struct ceph_osd_request *req)
{
req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
GFP_NOFS);
if (!req->r_pages) {
req->r_pages = mempool_alloc(fsc->wb_pagevec_pool, GFP_NOFS);
req->r_pages_from_pool = 1;
WARN_ON(!req->r_pages);
}
}
/*
* initiate async writeback
*/
static int ceph_writepages_start(struct address_space *mapping,
struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_fs_client *fsc;
pgoff_t index, start, end;
int range_whole = 0;
int should_loop = 1;
pgoff_t max_pages = 0, max_pages_ever = 0;
struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
struct pagevec pvec;
int done = 0;
int rc = 0;
unsigned wsize = 1 << inode->i_blkbits;
struct ceph_osd_request *req = NULL;
int do_sync;
u64 snap_size = 0;
/*
* Include a 'sync' in the OSD request if this is a data
* integrity write (e.g., O_SYNC write or fsync()), or if our
* cap is being revoked.
*/
do_sync = wbc->sync_mode == WB_SYNC_ALL;
if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
do_sync = 1;
dout("writepages_start %p dosync=%d (mode=%s)\n",
inode, do_sync,
wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
(wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
fsc = ceph_inode_to_client(inode);
if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
pr_warning("writepage_start %p on forced umount\n", inode);
return -EIO; /* we're in a forced umount, don't write! */
}
if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize)
wsize = fsc->mount_options->wsize;
if (wsize < PAGE_CACHE_SIZE)
wsize = PAGE_CACHE_SIZE;
max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
pagevec_init(&pvec, 0);
/* where to start/end? */
if (wbc->range_cyclic) {
start = mapping->writeback_index; /* Start from prev offset */
end = -1;
dout(" cyclic, start at %lu\n", start);
} else {
start = wbc->range_start >> PAGE_CACHE_SHIFT;
end = wbc->range_end >> PAGE_CACHE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
should_loop = 0;
dout(" not cyclic, %lu to %lu\n", start, end);
}
index = start;
retry:
/* find oldest snap context with dirty data */
ceph_put_snap_context(snapc);
snapc = get_oldest_context(inode, &snap_size);
if (!snapc) {
/* hmm, why does writepages get called when there
is no dirty data? */
dout(" no snap context with dirty data?\n");
goto out;
}
dout(" oldest snapc is %p seq %lld (%d snaps)\n",
snapc, snapc->seq, snapc->num_snaps);
if (last_snapc && snapc != last_snapc) {
/* if we switched to a newer snapc, restart our scan at the
* start of the original file range. */
dout(" snapc differs from last pass, restarting at %lu\n",
index);
index = start;
}
last_snapc = snapc;
while (!done && index <= end) {
unsigned i;
int first;
pgoff_t next;
int pvec_pages, locked_pages;
struct page *page;
int want;
u64 offset, len;
struct ceph_osd_request_head *reqhead;
struct ceph_osd_op *op;
long writeback_stat;
next = 0;
locked_pages = 0;
max_pages = max_pages_ever;
get_more_pages:
first = -1;
want = min(end - index,
min((pgoff_t)PAGEVEC_SIZE,
max_pages - (pgoff_t)locked_pages) - 1)
+ 1;
pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
PAGECACHE_TAG_DIRTY,
want);
dout("pagevec_lookup_tag got %d\n", pvec_pages);
if (!pvec_pages && !locked_pages)
break;
for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
page = pvec.pages[i];
dout("? %p idx %lu\n", page, page->index);
if (locked_pages == 0)
lock_page(page); /* first page */
else if (!trylock_page(page))
break;
/* only dirty pages, or our accounting breaks */
if (unlikely(!PageDirty(page)) ||
unlikely(page->mapping != mapping)) {
dout("!dirty or !mapping %p\n", page);
unlock_page(page);
break;
}
if (!wbc->range_cyclic && page->index > end) {
dout("end of range %p\n", page);
done = 1;
unlock_page(page);
break;
}
if (next && (page->index != next)) {
dout("not consecutive %p\n", page);
unlock_page(page);
break;
}
if (wbc->sync_mode != WB_SYNC_NONE) {
dout("waiting on writeback %p\n", page);
wait_on_page_writeback(page);
}
if ((snap_size && page_offset(page) > snap_size) ||
(!snap_size &&
page_offset(page) > i_size_read(inode))) {
dout("%p page eof %llu\n", page, snap_size ?
snap_size : i_size_read(inode));
done = 1;
unlock_page(page);
break;
}
if (PageWriteback(page)) {
dout("%p under writeback\n", page);
unlock_page(page);
break;
}
/* only if matching snap context */
pgsnapc = (void *)page->private;
if (pgsnapc->seq > snapc->seq) {
dout("page snapc %p %lld > oldest %p %lld\n",
pgsnapc, pgsnapc->seq, snapc, snapc->seq);
unlock_page(page);
if (!locked_pages)
continue; /* keep looking for snap */
break;
}
if (!clear_page_dirty_for_io(page)) {
dout("%p !clear_page_dirty_for_io\n", page);
unlock_page(page);
break;
}
/* ok */
if (locked_pages == 0) {
/* prepare async write request */
offset = (unsigned long long)page->index
<< PAGE_CACHE_SHIFT;
len = wsize;
req = ceph_osdc_new_request(&fsc->client->osdc,
&ci->i_layout,
ceph_vino(inode),
offset, &len,
CEPH_OSD_OP_WRITE,
CEPH_OSD_FLAG_WRITE |
CEPH_OSD_FLAG_ONDISK,
snapc, do_sync,
ci->i_truncate_seq,
ci->i_truncate_size,
&inode->i_mtime, true, 1, 0);
if (!req) {
rc = -ENOMEM;
unlock_page(page);
break;
}
max_pages = req->r_num_pages;
alloc_page_vec(fsc, req);
req->r_callback = writepages_finish;
req->r_inode = inode;
}
/* note position of first page in pvec */
if (first < 0)
first = i;
dout("%p will write page %p idx %lu\n",
inode, page, page->index);
writeback_stat =
atomic_long_inc_return(&fsc->writeback_count);
if (writeback_stat > CONGESTION_ON_THRESH(
fsc->mount_options->congestion_kb)) {
set_bdi_congested(&fsc->backing_dev_info,
BLK_RW_ASYNC);
}
set_page_writeback(page);
req->r_pages[locked_pages] = page;
locked_pages++;
next = page->index + 1;
}
/* did we get anything? */
if (!locked_pages)
goto release_pvec_pages;
if (i) {
int j;
BUG_ON(!locked_pages || first < 0);
if (pvec_pages && i == pvec_pages &&
locked_pages < max_pages) {
dout("reached end pvec, trying for more\n");
pagevec_reinit(&pvec);
goto get_more_pages;
}
/* shift unused pages over in the pvec... we
* will need to release them below. */
for (j = i; j < pvec_pages; j++) {
dout(" pvec leftover page %p\n",
pvec.pages[j]);
pvec.pages[j-i+first] = pvec.pages[j];
}
pvec.nr -= i-first;
}
/* submit the write */
offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
(u64)locked_pages << PAGE_CACHE_SHIFT);
dout("writepages got %d pages at %llu~%llu\n",
locked_pages, offset, len);
/* revise final length, page count */
req->r_num_pages = locked_pages;
reqhead = req->r_request->front.iov_base;
op = (void *)(reqhead + 1);
op->extent.length = cpu_to_le64(len);
op->payload_len = cpu_to_le32(len);
req->r_request->hdr.data_len = cpu_to_le32(len);
ceph_osdc_start_request(&fsc->client->osdc, req, true);
req = NULL;
/* continue? */
index = next;
wbc->nr_to_write -= locked_pages;
if (wbc->nr_to_write <= 0)
done = 1;
release_pvec_pages:
dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
pvec.nr ? pvec.pages[0] : NULL);
pagevec_release(&pvec);
if (locked_pages && !done)
goto retry;
}
if (should_loop && !done) {
/* more to do; loop back to beginning of file */
dout("writepages looping back to beginning of file\n");
should_loop = 0;
index = 0;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
mapping->writeback_index = index;
out:
if (req)
ceph_osdc_put_request(req);
if (rc > 0)
rc = 0; /* vfs expects us to return 0 */
ceph_put_snap_context(snapc);
dout("writepages done, rc = %d\n", rc);
return rc;
}
/*
* See if a given @snapc is either writeable, or already written.
*/
static int context_is_writeable_or_written(struct inode *inode,
struct ceph_snap_context *snapc)
{
struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
int ret = !oldest || snapc->seq <= oldest->seq;
ceph_put_snap_context(oldest);
return ret;
}
/*
* We are only allowed to write into/dirty the page if the page is
* clean, or already dirty within the same snap context.
*
* called with page locked.
* return success with page locked,
* or any failure (incl -EAGAIN) with page unlocked.
*/
static int ceph_update_writeable_page(struct file *file,
loff_t pos, unsigned len,
struct page *page)
{
struct inode *inode = file->f_dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
loff_t page_off = pos & PAGE_CACHE_MASK;
int pos_in_page = pos & ~PAGE_CACHE_MASK;
int end_in_page = pos_in_page + len;
loff_t i_size;
int r;
struct ceph_snap_context *snapc, *oldest;
retry_locked:
/* writepages currently holds page lock, but if we change that later, */
wait_on_page_writeback(page);
/* check snap context */
BUG_ON(!ci->i_snap_realm);
down_read(&mdsc->snap_rwsem);
BUG_ON(!ci->i_snap_realm->cached_context);
snapc = (void *)page->private;
if (snapc && snapc != ci->i_head_snapc) {
/*
* this page is already dirty in another (older) snap
* context! is it writeable now?
*/
oldest = get_oldest_context(inode, NULL);
up_read(&mdsc->snap_rwsem);
if (snapc->seq > oldest->seq) {
ceph_put_snap_context(oldest);
dout(" page %p snapc %p not current or oldest\n",
page, snapc);
/*
* queue for writeback, and wait for snapc to
* be writeable or written
*/
snapc = ceph_get_snap_context(snapc);
unlock_page(page);
ceph_queue_writeback(inode);
r = wait_event_interruptible(ci->i_cap_wq,
context_is_writeable_or_written(inode, snapc));
ceph_put_snap_context(snapc);
if (r == -ERESTARTSYS)
return r;
return -EAGAIN;
}
ceph_put_snap_context(oldest);
/* yay, writeable, do it now (without dropping page lock) */
dout(" page %p snapc %p not current, but oldest\n",
page, snapc);
if (!clear_page_dirty_for_io(page))
goto retry_locked;
r = writepage_nounlock(page, NULL);
if (r < 0)
goto fail_nosnap;
goto retry_locked;
}
if (PageUptodate(page)) {
dout(" page %p already uptodate\n", page);
return 0;
}
/* full page? */
if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
return 0;
/* past end of file? */
i_size = inode->i_size; /* caller holds i_mutex */
if (i_size + len > inode->i_sb->s_maxbytes) {
/* file is too big */
r = -EINVAL;
goto fail;
}
if (page_off >= i_size ||
(pos_in_page == 0 && (pos+len) >= i_size &&
end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
dout(" zeroing %p 0 - %d and %d - %d\n",
page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
zero_user_segments(page,
0, pos_in_page,
end_in_page, PAGE_CACHE_SIZE);
return 0;
}
/* we need to read it. */
up_read(&mdsc->snap_rwsem);
r = readpage_nounlock(file, page);
if (r < 0)
goto fail_nosnap;
goto retry_locked;
fail:
up_read(&mdsc->snap_rwsem);
fail_nosnap:
unlock_page(page);
return r;
}
/*
* We are only allowed to write into/dirty the page if the page is
* clean, or already dirty within the same snap context.
*/
static int ceph_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct inode *inode = file->f_dentry->d_inode;
struct page *page;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
int r;
do {
/* get a page */
page = grab_cache_page_write_begin(mapping, index, 0);
if (!page)
return -ENOMEM;
*pagep = page;
dout("write_begin file %p inode %p page %p %d~%d\n", file,
inode, page, (int)pos, (int)len);
r = ceph_update_writeable_page(file, pos, len, page);
} while (r == -EAGAIN);
return r;
}
/*
* we don't do anything in here that simple_write_end doesn't do
* except adjust dirty page accounting and drop read lock on
* mdsc->snap_rwsem.
*/
static int ceph_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = file->f_dentry->d_inode;
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
struct ceph_mds_client *mdsc = fsc->mdsc;
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
int check_cap = 0;
dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
inode, page, (int)pos, (int)copied, (int)len);
/* zero the stale part of the page if we did a short copy */
if (copied < len)
zero_user_segment(page, from+copied, len);
/* did file size increase? */
/* (no need for i_size_read(); we caller holds i_mutex */
if (pos+copied > inode->i_size)
check_cap = ceph_inode_set_size(inode, pos+copied);
if (!PageUptodate(page))
SetPageUptodate(page);
set_page_dirty(page);
unlock_page(page);
up_read(&mdsc->snap_rwsem);
page_cache_release(page);
if (check_cap)
ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
return copied;
}
/*
* we set .direct_IO to indicate direct io is supported, but since we
* intercept O_DIRECT reads and writes early, this function should
* never get called.
*/
static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
const struct iovec *iov,
loff_t pos, unsigned long nr_segs)
{
WARN_ON(1);
return -EINVAL;
}
const struct address_space_operations ceph_aops = {
.readpage = ceph_readpage,
.readpages = ceph_readpages,
.writepage = ceph_writepage,
.writepages = ceph_writepages_start,
.write_begin = ceph_write_begin,
.write_end = ceph_write_end,
.set_page_dirty = ceph_set_page_dirty,
.invalidatepage = ceph_invalidatepage,
.releasepage = ceph_releasepage,
.direct_IO = ceph_direct_io,
};
/*
* vm ops
*/
/*
* Reuse write_begin here for simplicity.
*/
static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct inode *inode = vma->vm_file->f_dentry->d_inode;
struct page *page = vmf->page;
struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
loff_t off = page->index << PAGE_CACHE_SHIFT;
loff_t size, len;
int ret;
size = i_size_read(inode);
if (off + PAGE_CACHE_SIZE <= size)
len = PAGE_CACHE_SIZE;
else
len = size & ~PAGE_CACHE_MASK;
dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
off, len, page, page->index);
lock_page(page);
ret = VM_FAULT_NOPAGE;
if ((off > size) ||
(page->mapping != inode->i_mapping))
goto out;
ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
if (ret == 0) {
/* success. we'll keep the page locked. */
set_page_dirty(page);
up_read(&mdsc->snap_rwsem);
ret = VM_FAULT_LOCKED;
} else {
if (ret == -ENOMEM)
ret = VM_FAULT_OOM;
else
ret = VM_FAULT_SIGBUS;
}
out:
dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
if (ret != VM_FAULT_LOCKED)
unlock_page(page);
return ret;
}
static struct vm_operations_struct ceph_vmops = {
.fault = filemap_fault,
.page_mkwrite = ceph_page_mkwrite,
};
int ceph_mmap(struct file *file, struct vm_area_struct *vma)
{
struct address_space *mapping = file->f_mapping;
if (!mapping->a_ops->readpage)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &ceph_vmops;
vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}
