Commit 2ae99a60 authored by Mark Fasheh's avatar Mark Fasheh
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ocfs2: Support creation of unwritten extents



This can now be trivially supported with re-use of our existing extend code.

ocfs2_allocate_unwritten_extents() takes a start offset and a byte length
and iterates over the inode, adding extents (marked as unwritten) until len
is reached. Existing extents are skipped over.
Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent b27b7cbc
......@@ -3726,6 +3726,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
u32 cpos,
u64 start_blk,
u32 new_clusters,
u8 flags,
struct ocfs2_alloc_context *meta_ac)
{
int status;
......@@ -3749,6 +3750,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
rec.e_cpos = cpu_to_le32(cpos);
rec.e_blkno = cpu_to_le64(start_blk);
rec.e_leaf_clusters = cpu_to_le16(new_clusters);
rec.e_flags = flags;
status = ocfs2_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,
&insert);
......
......@@ -34,6 +34,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
u32 cpos,
u64 start_blk,
u32 new_clusters,
u8 flags,
struct ocfs2_alloc_context *meta_ac);
struct ocfs2_cached_dealloc_ctxt;
int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
......
......@@ -1136,7 +1136,7 @@ static int ocfs2_write_cluster(struct address_space *mapping,
*/
tmp_pos = cpos;
ret = ocfs2_do_extend_allocation(OCFS2_SB(inode->i_sb), inode,
&tmp_pos, 1, wc->w_di_bh,
&tmp_pos, 1, 0, wc->w_di_bh,
wc->w_handle, data_ac,
meta_ac, NULL);
/*
......
......@@ -368,7 +368,7 @@ int ocfs2_do_extend_dir(struct super_block *sb,
u32 offset = OCFS2_I(dir)->ip_clusters;
status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, &offset,
1, parent_fe_bh, handle,
1, 0, parent_fe_bh, handle,
data_ac, meta_ac, NULL);
BUG_ON(status == -EAGAIN);
if (status < 0) {
......
......@@ -425,6 +425,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
struct inode *inode,
u32 *logical_offset,
u32 clusters_to_add,
int mark_unwritten,
struct buffer_head *fe_bh,
handle_t *handle,
struct ocfs2_alloc_context *data_ac,
......@@ -437,9 +438,13 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
enum ocfs2_alloc_restarted reason = RESTART_NONE;
u32 bit_off, num_bits;
u64 block;
u8 flags = 0;
BUG_ON(!clusters_to_add);
if (mark_unwritten)
flags = OCFS2_EXT_UNWRITTEN;
free_extents = ocfs2_num_free_extents(osb, inode, fe);
if (free_extents < 0) {
status = free_extents;
......@@ -489,7 +494,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
status = ocfs2_insert_extent(osb, handle, inode, fe_bh,
*logical_offset, block, num_bits,
meta_ac);
flags, meta_ac);
if (status < 0) {
mlog_errno(status);
goto leave;
......@@ -522,9 +527,11 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
* For a given allocation, determine which allocators will need to be
* accessed, and lock them, reserving the appropriate number of bits.
*
* Called from ocfs2_extend_allocation() for file systems which don't
* support holes, and from ocfs2_write() for file systems which
* understand sparse inodes.
* Sparse file systems call this from ocfs2_write_begin_nolock()
* and ocfs2_allocate_unwritten_extents().
*
* File systems which don't support holes call this from
* ocfs2_extend_allocation().
*/
int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
u32 clusters_to_add, u32 extents_to_split,
......@@ -595,14 +602,13 @@ int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
return ret;
}
static int ocfs2_extend_allocation(struct inode *inode,
u32 clusters_to_add)
static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
u32 clusters_to_add, int mark_unwritten)
{
int status = 0;
int restart_func = 0;
int drop_alloc_sem = 0;
int credits;
u32 prev_clusters, logical_start;
u32 prev_clusters;
struct buffer_head *bh = NULL;
struct ocfs2_dinode *fe = NULL;
handle_t *handle = NULL;
......@@ -617,7 +623,7 @@ static int ocfs2_extend_allocation(struct inode *inode,
* This function only exists for file systems which don't
* support holes.
*/
BUG_ON(ocfs2_sparse_alloc(osb));
BUG_ON(mark_unwritten && !ocfs2_sparse_alloc(osb));
status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &bh,
OCFS2_BH_CACHED, inode);
......@@ -633,18 +639,9 @@ static int ocfs2_extend_allocation(struct inode *inode,
goto leave;
}
logical_start = OCFS2_I(inode)->ip_clusters;
restart_all:
BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);
/* blocks peope in read/write from reading our allocation
* until we're done changing it. We depend on i_mutex to block
* other extend/truncate calls while we're here. Ordering wrt
* start_trans is important here -- always do it before! */
down_write(&OCFS2_I(inode)->ip_alloc_sem);
drop_alloc_sem = 1;
status = ocfs2_lock_allocators(inode, fe, clusters_to_add, 0, &data_ac,
&meta_ac);
if (status) {
......@@ -678,6 +675,7 @@ static int ocfs2_extend_allocation(struct inode *inode,
inode,
&logical_start,
clusters_to_add,
mark_unwritten,
bh,
handle,
data_ac,
......@@ -730,10 +728,6 @@ static int ocfs2_extend_allocation(struct inode *inode,
OCFS2_I(inode)->ip_clusters, i_size_read(inode));
leave:
if (drop_alloc_sem) {
up_write(&OCFS2_I(inode)->ip_alloc_sem);
drop_alloc_sem = 0;
}
if (handle) {
ocfs2_commit_trans(osb, handle);
handle = NULL;
......@@ -759,6 +753,25 @@ static int ocfs2_extend_allocation(struct inode *inode,
return status;
}
static int ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
u32 clusters_to_add, int mark_unwritten)
{
int ret;
/*
* The alloc sem blocks peope in read/write from reading our
* allocation until we're done changing it. We depend on
* i_mutex to block other extend/truncate calls while we're
* here.
*/
down_write(&OCFS2_I(inode)->ip_alloc_sem);
ret = __ocfs2_extend_allocation(inode, logical_start, clusters_to_add,
mark_unwritten);
up_write(&OCFS2_I(inode)->ip_alloc_sem);
return ret;
}
/* Some parts of this taken from generic_cont_expand, which turned out
* to be too fragile to do exactly what we need without us having to
* worry about recursive locking in ->prepare_write() and
......@@ -900,7 +913,9 @@ static int ocfs2_extend_file(struct inode *inode,
}
if (clusters_to_add) {
ret = ocfs2_extend_allocation(inode, clusters_to_add);
ret = ocfs2_extend_allocation(inode,
OCFS2_I(inode)->ip_clusters,
clusters_to_add, 0);
if (ret < 0) {
mlog_errno(ret);
goto out_unlock;
......@@ -1176,6 +1191,64 @@ static int ocfs2_check_range_for_holes(struct inode *inode, loff_t pos,
return ret;
}
/*
* Allocate enough extents to cover the region starting at byte offset
* start for len bytes. Existing extents are skipped, any extents
* added are marked as "unwritten".
*/
static int ocfs2_allocate_unwritten_extents(struct inode *inode,
u64 start, u64 len)
{
int ret;
u32 cpos, phys_cpos, clusters, alloc_size;
/*
* We consider both start and len to be inclusive.
*/
cpos = start >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
clusters = ocfs2_clusters_for_bytes(inode->i_sb, start + len);
clusters -= cpos;
while (clusters) {
ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
&alloc_size, NULL);
if (ret) {
mlog_errno(ret);
goto out;
}
/*
* Hole or existing extent len can be arbitrary, so
* cap it to our own allocation request.
*/
if (alloc_size > clusters)
alloc_size = clusters;
if (phys_cpos) {
/*
* We already have an allocation at this
* region so we can safely skip it.
*/
goto next;
}
ret = __ocfs2_extend_allocation(inode, cpos, alloc_size, 1);
if (ret) {
if (ret != -ENOSPC)
mlog_errno(ret);
goto out;
}
next:
cpos += alloc_size;
clusters -= alloc_size;
}
ret = 0;
out:
return ret;
}
static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
loff_t *ppos,
size_t count,
......
......@@ -39,13 +39,14 @@ enum ocfs2_alloc_restarted {
};
int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
struct inode *inode,
u32 *cluster_start,
u32 *logical_offset,
u32 clusters_to_add,
int mark_unwritten,
struct buffer_head *fe_bh,
handle_t *handle,
struct ocfs2_alloc_context *data_ac,
struct ocfs2_alloc_context *meta_ac,
enum ocfs2_alloc_restarted *reason);
enum ocfs2_alloc_restarted *reason_ret);
int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
u32 clusters_to_add, u32 extents_to_split,
struct ocfs2_alloc_context **data_ac,
......
......@@ -1674,7 +1674,7 @@ static int ocfs2_symlink(struct inode *dir,
u32 offset = 0;
inode->i_op = &ocfs2_symlink_inode_operations;
status = ocfs2_do_extend_allocation(osb, inode, &offset, 1,
status = ocfs2_do_extend_allocation(osb, inode, &offset, 1, 0,
new_fe_bh,
handle, data_ac, NULL,
NULL);
......
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