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-rw-r--r--fs/ceph/addr.c73
1 files changed, 39 insertions, 34 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 23bb0ceabe3..412593703d1 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -5,6 +5,7 @@
#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>
@@ -336,16 +337,15 @@ out:
/*
* Get ref for the oldest snapc for an inode with dirty data... that is, the
* only snap context we are allowed to write back.
- *
- * Caller holds i_lock.
*/
-static struct ceph_snap_context *__get_oldest_context(struct inode *inode,
- u64 *snap_size)
+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);
@@ -356,21 +356,11 @@ static struct ceph_snap_context *__get_oldest_context(struct inode *inode,
break;
}
}
- if (!snapc && ci->i_snap_realm) {
- snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
+ if (!snapc && ci->i_head_snapc) {
+ snapc = ceph_get_snap_context(ci->i_head_snapc);
dout(" head snapc %p has %d dirty pages\n",
snapc, ci->i_wrbuffer_ref_head);
}
- return snapc;
-}
-
-static struct ceph_snap_context *get_oldest_context(struct inode *inode,
- u64 *snap_size)
-{
- struct ceph_snap_context *snapc = NULL;
-
- spin_lock(&inode->i_lock);
- snapc = __get_oldest_context(inode, snap_size);
spin_unlock(&inode->i_lock);
return snapc;
}
@@ -391,7 +381,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
int len = PAGE_CACHE_SIZE;
loff_t i_size;
int err = 0;
- struct ceph_snap_context *snapc;
+ struct ceph_snap_context *snapc, *oldest;
u64 snap_size = 0;
long writeback_stat;
@@ -412,13 +402,16 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
dout("writepage %p page %p not dirty?\n", inode, page);
goto out;
}
- if (snapc != get_oldest_context(inode, &snap_size)) {
+ 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)
@@ -457,7 +450,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
ClearPagePrivate(page);
end_page_writeback(page);
ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
- ceph_put_snap_context(snapc);
+ ceph_put_snap_context(snapc); /* page's reference */
out:
return err;
}
@@ -557,9 +550,9 @@ static void writepages_finish(struct ceph_osd_request *req,
dout("inode %p skipping page %p\n", inode, page);
wbc->pages_skipped++;
}
+ ceph_put_snap_context((void *)page->private);
page->private = 0;
ClearPagePrivate(page);
- ceph_put_snap_context(snapc);
dout("unlocking %d %p\n", i, page);
end_page_writeback(page);
@@ -617,7 +610,7 @@ static int ceph_writepages_start(struct address_space *mapping,
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;
+ struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
struct pagevec pvec;
int done = 0;
int rc = 0;
@@ -769,9 +762,10 @@ get_more_pages:
}
/* only if matching snap context */
- if (snapc != (void *)page->private) {
- dout("page snapc %p != oldest %p\n",
- (void *)page->private, snapc);
+ 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 */
@@ -913,12 +907,19 @@ 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);
- return !oldest || snapc->seq <= oldest->seq;
+ 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,
@@ -931,8 +932,8 @@ static int ceph_update_writeable_page(struct file *file,
int pos_in_page = pos & ~PAGE_CACHE_MASK;
int end_in_page = pos_in_page + len;
loff_t i_size;
- struct ceph_snap_context *snapc;
int r;
+ struct ceph_snap_context *snapc, *oldest;
retry_locked:
/* writepages currently holds page lock, but if we change that later, */
@@ -942,30 +943,34 @@ retry_locked:
BUG_ON(!ci->i_snap_realm);
down_read(&mdsc->snap_rwsem);
BUG_ON(!ci->i_snap_realm->cached_context);
- if (page->private &&
- (void *)page->private != 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?
*/
- snapc = get_oldest_context(inode, NULL);
+ oldest = get_oldest_context(inode, NULL);
up_read(&mdsc->snap_rwsem);
- if (snapc != (void *)page->private) {
+ if (snapc->seq > oldest->seq) {
+ ceph_put_snap_context(oldest);
dout(" page %p snapc %p not current or oldest\n",
- page, (void *)page->private);
+ page, snapc);
/*
* queue for writeback, and wait for snapc to
* be writeable or written
*/
- snapc = ceph_get_snap_context((void *)page->private);
+ snapc = ceph_get_snap_context(snapc);
unlock_page(page);
ceph_queue_writeback(inode);
- wait_event_interruptible(ci->i_cap_wq,
+ 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",
@@ -1035,7 +1040,7 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
int r;
do {
- /* get a page*/
+ /* get a page */
page = grab_cache_page_write_begin(mapping, index, 0);
if (!page)
return -ENOMEM;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-15 17:33:44 +0000