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ocfs2: support writing of unwritten extents
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Update the write code to detect when the user is asking to write to an
unwritten extent. Like writing to a hole, we must zero the region between
the write and the cluster boundaries. Most of the existing cluster zeroing
logic can be re-used with some additional checks for the unwritten flag on
extent records.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
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Mark Fasheh committed Jul 11, 2007
1 parent 0d172ba commit b27b7cb
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Showing 3 changed files with 84 additions and 26 deletions.
94 changes: 74 additions & 20 deletions fs/ocfs2/aops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -782,8 +782,14 @@ struct ocfs2_write_cluster_desc {
* filled.
*/
unsigned c_new;
unsigned c_unwritten;
};

static inline int ocfs2_should_zero_cluster(struct ocfs2_write_cluster_desc *d)
{
return d->c_new || d->c_unwritten;
}

struct ocfs2_write_ctxt {
/* Logical cluster position / len of write */
u32 w_cpos;
Expand Down Expand Up @@ -829,6 +835,8 @@ struct ocfs2_write_ctxt {
handle_t *w_handle;

struct buffer_head *w_di_bh;

struct ocfs2_cached_dealloc_ctxt w_dealloc;
};

static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
Expand Down Expand Up @@ -868,6 +876,8 @@ static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
else
wc->w_large_pages = 0;

ocfs2_init_dealloc_ctxt(&wc->w_dealloc);

*wcp = wc;

return 0;
Expand Down Expand Up @@ -1103,16 +1113,19 @@ static int ocfs2_grab_pages_for_write(struct address_space *mapping,
* Prepare a single cluster for write one cluster into the file.
*/
static int ocfs2_write_cluster(struct address_space *mapping,
u32 phys, struct ocfs2_alloc_context *data_ac,
u32 phys, unsigned int unwritten,
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, new, should_zero = 0;
u64 v_blkno, p_blkno;
struct inode *inode = mapping->host;

new = phys == 0 ? 1 : 0;
if (new || unwritten)
should_zero = 1;

if (new) {
u32 tmp_pos;
Expand Down Expand Up @@ -1142,11 +1155,20 @@ static int ocfs2_write_cluster(struct address_space *mapping,
mlog_errno(ret);
goto out;
}
} else if (unwritten) {
ret = ocfs2_mark_extent_written(inode, wc->w_di_bh,
wc->w_handle, cpos, 1, phys,
meta_ac, &wc->w_dealloc);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
}

if (should_zero)
v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, cpos);
} else {
else
v_blkno = user_pos >> inode->i_sb->s_blocksize_bits;
}

/*
* The only reason this should fail is due to an inability to
Expand All @@ -1169,7 +1191,8 @@ static int ocfs2_write_cluster(struct address_space *mapping,

tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
wc->w_pages[i], cpos,
user_pos, user_len, new);
user_pos, user_len,
should_zero);
if (tmpret) {
mlog_errno(tmpret);
if (ret == 0)
Expand Down Expand Up @@ -1200,8 +1223,9 @@ static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
for (i = 0; i < wc->w_clen; i++) {
desc = &wc->w_desc[i];

ret = ocfs2_write_cluster(mapping, desc->c_phys, data_ac,
meta_ac, wc, desc->c_cpos, pos, len);
ret = ocfs2_write_cluster(mapping, desc->c_phys,
desc->c_unwritten, data_ac, meta_ac,
wc, desc->c_cpos, pos, len);
if (ret) {
mlog_errno(ret);
goto out;
Expand Down Expand Up @@ -1242,19 +1266,19 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
if (wc->w_large_pages) {
/*
* We only care about the 1st and last cluster within
* our range and whether they are holes or not. Either
* our range and whether they should be zero'd or not. Either
* value may be extended out to the start/end of a
* newly allocated cluster.
*/
desc = &wc->w_desc[0];
if (desc->c_new)
if (ocfs2_should_zero_cluster(desc))
ocfs2_figure_cluster_boundaries(osb,
desc->c_cpos,
&wc->w_target_from,
NULL);

desc = &wc->w_desc[wc->w_clen - 1];
if (desc->c_new)
if (ocfs2_should_zero_cluster(desc))
ocfs2_figure_cluster_boundaries(osb,
desc->c_cpos,
NULL,
Expand All @@ -1268,28 +1292,52 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
/*
* Populate each single-cluster write descriptor in the write context
* with information about the i/o to be done.
*
* Returns the number of clusters that will have to be allocated, as
* well as a worst case estimate of the number of extent records that
* would have to be created during a write to an unwritten region.
*/
static int ocfs2_populate_write_desc(struct inode *inode,
struct ocfs2_write_ctxt *wc,
unsigned int *clusters_to_alloc)
unsigned int *clusters_to_alloc,
unsigned int *extents_to_split)
{
int ret;
struct ocfs2_write_cluster_desc *desc;
unsigned int num_clusters = 0;
unsigned int ext_flags = 0;
u32 phys = 0;
int i;

*clusters_to_alloc = 0;
*extents_to_split = 0;

for (i = 0; i < wc->w_clen; i++) {
desc = &wc->w_desc[i];
desc->c_cpos = wc->w_cpos + i;

if (num_clusters == 0) {
/*
* Need to look up the next extent record.
*/
ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
&num_clusters, NULL);
&num_clusters, &ext_flags);
if (ret) {
mlog_errno(ret);
goto out;
}

/*
* Assume worst case - that we're writing in
* the middle of the extent.
*
* We can assume that the write proceeds from
* left to right, in which case the extent
* insert code is smart enough to coalesce the
* next splits into the previous records created.
*/
if (ext_flags & OCFS2_EXT_UNWRITTEN)
*extents_to_split = *extents_to_split + 2;
} else if (phys) {
/*
* Only increment phys if it doesn't describe
Expand All @@ -1303,6 +1351,8 @@ static int ocfs2_populate_write_desc(struct inode *inode,
desc->c_new = 1;
*clusters_to_alloc = *clusters_to_alloc + 1;
}
if (ext_flags & OCFS2_EXT_UNWRITTEN)
desc->c_unwritten = 1;

num_clusters--;
}
Expand All @@ -1318,7 +1368,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
struct buffer_head *di_bh, struct page *mmap_page)
{
int ret, credits = OCFS2_INODE_UPDATE_CREDITS;
unsigned int clusters_to_alloc = 0;
unsigned int clusters_to_alloc, extents_to_split;
struct ocfs2_write_ctxt *wc;
struct inode *inode = mapping->host;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
Expand All @@ -1333,7 +1383,8 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
return ret;
}

ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc);
ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
&extents_to_split);
if (ret) {
mlog_errno(ret);
goto out;
Expand All @@ -1347,14 +1398,14 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
* write out. An allocation requires that we write the entire
* cluster range.
*/
if (clusters_to_alloc > 0) {
if (clusters_to_alloc || extents_to_split) {
/*
* XXX: We are stretching the limits of
* ocfs2_lock_allocators(). It greately over-estimates
* ocfs2_lock_allocators(). It greatly over-estimates
* the work to be done.
*/
ret = ocfs2_lock_allocators(inode, di, clusters_to_alloc,
&data_ac, &meta_ac);
extents_to_split, &data_ac, &meta_ac);
if (ret) {
mlog_errno(ret);
goto out;
Expand All @@ -1365,7 +1416,8 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,

}

ocfs2_set_target_boundaries(osb, wc, pos, len, clusters_to_alloc);
ocfs2_set_target_boundaries(osb, wc, pos, len,
clusters_to_alloc + extents_to_split);

handle = ocfs2_start_trans(osb, credits);
if (IS_ERR(handle)) {
Expand Down Expand Up @@ -1393,7 +1445,8 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
* extent.
*/
ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos,
clusters_to_alloc, mmap_page);
clusters_to_alloc + extents_to_split,
mmap_page);
if (ret) {
mlog_errno(ret);
goto out_commit;
Expand Down Expand Up @@ -1538,11 +1591,12 @@ int ocfs2_write_end_nolock(struct address_space *mapping,
inode->i_mtime = inode->i_ctime = CURRENT_TIME;
di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);

ocfs2_journal_dirty(handle, wc->w_di_bh);

ocfs2_commit_trans(osb, handle);

ocfs2_run_deallocs(osb, &wc->w_dealloc);

ocfs2_free_write_ctxt(wc);

return copied;
Expand Down
14 changes: 9 additions & 5 deletions fs/ocfs2/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -527,20 +527,21 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
* understand sparse inodes.
*/
int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
u32 clusters_to_add,
u32 clusters_to_add, u32 extents_to_split,
struct ocfs2_alloc_context **data_ac,
struct ocfs2_alloc_context **meta_ac)
{
int ret, num_free_extents;
unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

*meta_ac = NULL;
*data_ac = NULL;

mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "
"clusters_to_add = %u\n",
"clusters_to_add = %u, extents_to_split = %u\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno, i_size_read(inode),
le32_to_cpu(di->i_clusters), clusters_to_add);
le32_to_cpu(di->i_clusters), clusters_to_add, extents_to_split);

num_free_extents = ocfs2_num_free_extents(osb, inode, di);
if (num_free_extents < 0) {
Expand All @@ -558,9 +559,12 @@ int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
*
* Most of the time we'll only be seeing this 1 cluster at a time
* anyway.
*
* Always lock for any unwritten extents - we might want to
* add blocks during a split.
*/
if (!num_free_extents ||
(ocfs2_sparse_alloc(osb) && num_free_extents < clusters_to_add)) {
(ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
ret = ocfs2_reserve_new_metadata(osb, di, meta_ac);
if (ret < 0) {
if (ret != -ENOSPC)
Expand Down Expand Up @@ -641,7 +645,7 @@ static int ocfs2_extend_allocation(struct inode *inode,
down_write(&OCFS2_I(inode)->ip_alloc_sem);
drop_alloc_sem = 1;

status = ocfs2_lock_allocators(inode, fe, clusters_to_add, &data_ac,
status = ocfs2_lock_allocators(inode, fe, clusters_to_add, 0, &data_ac,
&meta_ac);
if (status) {
mlog_errno(status);
Expand Down
2 changes: 1 addition & 1 deletion fs/ocfs2/file.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
struct ocfs2_alloc_context *meta_ac,
enum ocfs2_alloc_restarted *reason);
int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
u32 clusters_to_add,
u32 clusters_to_add, u32 extents_to_split,
struct ocfs2_alloc_context **data_ac,
struct ocfs2_alloc_context **meta_ac);
int ocfs2_setattr(struct dentry *dentry, struct iattr *attr);
Expand Down

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