Commit b46637d5 authored by Ryan Ding's avatar Ryan Ding Committed by Linus Torvalds
Browse files

ocfs2: use c_new to indicate newly allocated extents

To support direct io in ocfs2_write_begin_nolock & ocfs2_write_end_nolock.

There is a problem in ocfs2's direct io implement: if system crashed
after extents allocated, and before data return, we will get a extent
with dirty data on disk.  This problem violate the journal=order
semantics, which means meta changes take effect after data written to
disk.  To resolve this issue, direct write can use the UNWRITTEN flag to
describe a extent during direct data writeback.  The direct write
procedure should act in the following order:

phase 1: alloc extent with UNWRITTEN flag
phase 2: submit direct data to disk, add zero page to page cache
phase 3: clear UNWRITTEN flag when data has been written to disk

This patch is to change the 'c_unwritten' member of
ocfs2_write_cluster_desc to 'c_clear_unwritten'.  Means whether to clear
the unwritten flag.  It do not care if a extent is allocated or not.
And use 'c_new' to specify a newly allocated extent.  So the direct io
procedure can use c_clear_unwritten to control the UNWRITTEN bit on

Signed-off-by: default avatarRyan Ding <>
Reviewed-by: default avatarJunxiao Bi <>
Cc: Joseph Qi <>
Cc: Mark Fasheh <>
Cc: Joel Becker <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent c1ad1e3c
......@@ -1212,7 +1212,7 @@ struct ocfs2_write_cluster_desc {
* filled.
unsigned c_new;
unsigned c_unwritten;
unsigned c_clear_unwritten;
unsigned c_needs_zero;
......@@ -1588,19 +1588,19 @@ out:
* Prepare a single cluster for write one cluster into the file.
static int ocfs2_write_cluster(struct address_space *mapping,
u32 phys, unsigned int unwritten,
u32 phys, unsigned int new,
unsigned int clear_unwritten,
unsigned int should_zero,
struct ocfs2_alloc_context *data_ac,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_write_ctxt *wc, u32 cpos,
loff_t user_pos, unsigned user_len)
int ret, i, new;
int ret, i;
u64 v_blkno, p_blkno;
struct inode *inode = mapping->host;
struct ocfs2_extent_tree et;
new = phys == 0 ? 1 : 0;
if (new) {
u32 tmp_pos;
......@@ -1610,9 +1610,9 @@ static int ocfs2_write_cluster(struct address_space *mapping,
tmp_pos = cpos;
ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode,
&tmp_pos, 1, 0, wc->w_di_bh,
wc->w_handle, data_ac,
meta_ac, NULL);
&tmp_pos, 1, !clear_unwritten,
wc->w_di_bh, wc->w_handle,
data_ac, meta_ac, NULL);
* This shouldn't happen because we must have already
* calculated the correct meta data allocation required. The
......@@ -1629,7 +1629,7 @@ static int ocfs2_write_cluster(struct address_space *mapping,
goto out;
} else if (unwritten) {
} else if (clear_unwritten) {
ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
ret = ocfs2_mark_extent_written(inode, &et,
......@@ -1712,7 +1712,8 @@ static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
local_len = osb->s_clustersize - cluster_off;
ret = ocfs2_write_cluster(mapping, desc->c_phys,
data_ac, meta_ac,
wc, desc->c_cpos, pos, local_len);
......@@ -1857,11 +1858,12 @@ static int ocfs2_populate_write_desc(struct inode *inode,
if (phys == 0) {
desc->c_new = 1;
desc->c_needs_zero = 1;
desc->c_clear_unwritten = 1;
*clusters_to_alloc = *clusters_to_alloc + 1;
if (ext_flags & OCFS2_EXT_UNWRITTEN) {
desc->c_unwritten = 1;
desc->c_clear_unwritten = 1;
desc->c_needs_zero = 1;
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