#include <linux/pagevec.h>
#include <linux/mpage.h>
#include <linux/fs.h>
+#include <linux/writeback.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>
return 0;
}
+/**
+ * gfs2_writepages - Write a bunch of dirty pages back to disk
+ * @mapping: The mapping to write
+ * @wbc: Write-back control
+ *
+ * For journaled files and/or ordered writes this just falls back to the
+ * kernel's default writepages path for now. We will probably want to change
+ * that eventually (i.e. when we look at allocate on flush).
+ *
+ * For the data=writeback case though we can already ignore buffer heads
+ * and write whole extents at once. This is a big reduction in the
+ * number of I/O requests we send and the bmap calls we make in this case.
+ */
+static int gfs2_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct inode *inode = mapping->host;
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+
+ if (sdp->sd_args.ar_data == GFS2_DATA_WRITEBACK && !gfs2_is_jdata(ip))
+ return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
+
+ return generic_writepages(mapping, wbc);
+}
+
/**
* stuffed_readpage - Fill in a Linux page with stuffed file data
* @ip: the inode
void *kaddr;
int error;
- BUG_ON(page->index);
+ /*
+ * Due to the order of unstuffing files and ->nopage(), we can be
+ * asked for a zero page in the case of a stuffed file being extended,
+ * so we need to supply one here. It doesn't happen often.
+ */
+ if (unlikely(page->index)) {
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr, 0, PAGE_CACHE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ return 0;
+ }
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
ip->i_di.di_size);
memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
kunmap_atomic(kaddr, KM_USER0);
-
+ flush_dcache_page(page);
brelse(dibh);
-
SetPageUptodate(page);
return 0;
out:
return error;
out_unlock:
- if (error == GLR_TRYFAILED)
- error = AOP_TRUNCATED_PAGE;
unlock_page(page);
+ if (error == GLR_TRYFAILED) {
+ error = AOP_TRUNCATED_PAGE;
+ yield();
+ }
if (do_unlock)
gfs2_holder_uninit(&gh);
goto out;
* the page lock and the glock) and return having done no I/O. Its
* obviously not something we'd want to do on too regular a basis.
* Any I/O we ignore at this time will be done via readpage later.
- * 2. We have to handle stuffed files here too.
+ * 2. We don't handle stuffed files here we let readpage do the honours.
* 3. mpage_readpages() does most of the heavy lifting in the common case.
* 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
* 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_holder gh;
- unsigned page_idx;
- int ret;
+ int ret = 0;
int do_unlock = 0;
if (likely(file != &gfs2_internal_file_sentinel)) {
goto out_unlock;
}
skip_lock:
- if (gfs2_is_stuffed(ip)) {
- struct pagevec lru_pvec;
- pagevec_init(&lru_pvec, 0);
- for (page_idx = 0; page_idx < nr_pages; page_idx++) {
- struct page *page = list_entry(pages->prev, struct page, lru);
- prefetchw(&page->flags);
- list_del(&page->lru);
- if (!add_to_page_cache(page, mapping,
- page->index, GFP_KERNEL)) {
- ret = stuffed_readpage(ip, page);
- unlock_page(page);
- if (!pagevec_add(&lru_pvec, page))
- __pagevec_lru_add(&lru_pvec);
- } else {
- page_cache_release(page);
- }
- }
- pagevec_lru_add(&lru_pvec);
- ret = 0;
- } else {
- /* What we really want to do .... */
+ if (!gfs2_is_stuffed(ip))
ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
- }
if (do_unlock) {
gfs2_glock_dq_m(1, &gh);
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
error = gfs2_glock_nq_atime(&ip->i_gh);
if (unlikely(error)) {
- if (error == GLR_TRYFAILED)
+ if (error == GLR_TRYFAILED) {
+ unlock_page(page);
error = AOP_TRUNCATED_PAGE;
+ yield();
+ }
goto out_uninit;
}
gfs2_quota_unlock(ip);
gfs2_alloc_put(ip);
}
+ unlock_page(page);
gfs2_glock_dq_m(1, &ip->i_gh);
+ lock_page(page);
gfs2_holder_uninit(&ip->i_gh);
return 0;
gfs2_quota_unlock(ip);
gfs2_alloc_put(ip);
}
+ unlock_page(page);
gfs2_glock_dq_m(1, &ip->i_gh);
+ lock_page(page);
gfs2_holder_uninit(&ip->i_gh);
fail_nounlock:
ClearPageUptodate(page);
return;
}
+/**
+ * gfs2_ok_for_dio - check that dio is valid on this file
+ * @ip: The inode
+ * @rw: READ or WRITE
+ * @offset: The offset at which we are reading or writing
+ *
+ * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
+ * 1 (to accept the i/o request)
+ */
+static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
+{
+ /*
+ * Should we return an error here? I can't see that O_DIRECT for
+ * a journaled file makes any sense. For now we'll silently fall
+ * back to buffered I/O, likewise we do the same for stuffed
+ * files since they are (a) small and (b) unaligned.
+ */
+ if (gfs2_is_jdata(ip))
+ return 0;
+
+ if (gfs2_is_stuffed(ip))
+ return 0;
+
+ if (offset > i_size_read(&ip->i_inode))
+ return 0;
+ return 1;
+}
+
+
+
static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov, loff_t offset,
unsigned long nr_segs)
struct gfs2_holder gh;
int rv;
- if (rw == READ)
- mutex_lock(&inode->i_mutex);
/*
- * Shared lock, even if its a write, since we do no allocation
- * on this path. All we need change is atime.
+ * Deferred lock, even if its a write, since we do no allocation
+ * on this path. All we need change is atime, and this lock mode
+ * ensures that other nodes have flushed their buffered read caches
+ * (i.e. their page cache entries for this inode). We do not,
+ * unfortunately have the option of only flushing a range like
+ * the VFS does.
*/
- gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
+ gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, GL_ATIME, &gh);
rv = gfs2_glock_nq_atime(&gh);
if (rv)
- goto out;
-
- if (offset > i_size_read(inode))
- goto out;
-
- /*
- * Should we return an error here? I can't see that O_DIRECT for
- * a journaled file makes any sense. For now we'll silently fall
- * back to buffered I/O, likewise we do the same for stuffed
- * files since they are (a) small and (b) unaligned.
- */
- if (gfs2_is_jdata(ip))
- goto out;
-
- if (gfs2_is_stuffed(ip))
- goto out;
-
- rv = blockdev_direct_IO_own_locking(rw, iocb, inode,
- inode->i_sb->s_bdev,
- iov, offset, nr_segs,
- gfs2_get_block_direct, NULL);
+ return rv;
+ rv = gfs2_ok_for_dio(ip, rw, offset);
+ if (rv != 1)
+ goto out; /* dio not valid, fall back to buffered i/o */
+
+ rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
+ iov, offset, nr_segs,
+ gfs2_get_block_direct, NULL);
out:
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
- if (rw == READ)
- mutex_unlock(&inode->i_mutex);
-
return rv;
}
const struct address_space_operations gfs2_file_aops = {
.writepage = gfs2_writepage,
+ .writepages = gfs2_writepages,
.readpage = gfs2_readpage,
.readpages = gfs2_readpages,
.sync_page = block_sync_page,
projects / powerpc.git / blobdiff