[Ocfs2-devel] [PATCH 01/15] ocfs2: move nonsparse hole-filling into
ocfs2_write_begin()
Mark Fasheh
mark.fasheh at oracle.com
Wed Sep 19 13:12:17 PDT 2007
By doing this, we can remove any higher level logic which has to have
knowledge of btree functionality - any callers of ocfs2_write_begin() can
now expect it to do anything necessary to prepare the inode for new data.
Signed-off-by: Mark Fasheh <mark.fasheh at oracle.com>
---
fs/ocfs2/aops.c | 40 +++++++++-
fs/ocfs2/file.c | 217 ++++++++++++++++++++-----------------------------------
fs/ocfs2/file.h | 2 +
3 files changed, 115 insertions(+), 144 deletions(-)
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 460d440..97394c5 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -301,12 +301,8 @@ int ocfs2_prepare_write_nolock(struct inode *inode, struct page *page,
{
int ret;
- down_read(&OCFS2_I(inode)->ip_alloc_sem);
-
ret = block_prepare_write(page, from, to, ocfs2_get_block);
- up_read(&OCFS2_I(inode)->ip_alloc_sem);
-
return ret;
}
@@ -1353,6 +1349,36 @@ out:
return ret;
}
+/*
+ * This function only does anything for file systems which can't
+ * handle sparse files.
+ *
+ * What we want to do here is fill in any hole between the current end
+ * of allocation and the end of our write. That way the rest of the
+ * write path can treat it as an non-allocating write, which has no
+ * special case code for sparse/nonsparse files.
+ */
+static int ocfs2_expand_nonsparse_inode(struct inode *inode, loff_t pos,
+ unsigned len,
+ struct ocfs2_write_ctxt *wc)
+{
+ int ret;
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ loff_t newsize = pos + len;
+
+ if (ocfs2_sparse_alloc(osb))
+ return 0;
+
+ if (newsize <= i_size_read(inode))
+ return 0;
+
+ ret = ocfs2_extend_no_holes(inode, newsize, newsize - len);
+ if (ret)
+ mlog_errno(ret);
+
+ return ret;
+}
+
int ocfs2_write_begin_nolock(struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata,
@@ -1374,6 +1400,12 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
return ret;
}
+ ret = ocfs2_expand_nonsparse_inode(inode, pos, len, wc);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
&extents_to_split);
if (ret) {
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 4ffa715..429ebcb 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -780,25 +780,6 @@ leave:
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
@@ -890,25 +871,47 @@ out:
return ret;
}
-/*
- * A tail_to_skip value > 0 indicates that we're being called from
- * ocfs2_file_aio_write(). This has the following implications:
- *
- * - we don't want to update i_size
- * - di_bh will be NULL, which is fine because it's only used in the
- * case where we want to update i_size.
- * - ocfs2_zero_extend() will then only be filling the hole created
- * between i_size and the start of the write.
- */
+int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size, u64 zero_to)
+{
+ int ret;
+ u32 clusters_to_add;
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+ clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size);
+ if (clusters_to_add < oi->ip_clusters)
+ clusters_to_add = 0;
+ else
+ clusters_to_add -= oi->ip_clusters;
+
+ if (clusters_to_add) {
+ ret = __ocfs2_extend_allocation(inode, oi->ip_clusters,
+ clusters_to_add, 0);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+ }
+
+ /*
+ * Call this even if we don't add any clusters to the tree. We
+ * still need to zero the area between the old i_size and the
+ * new i_size.
+ */
+ ret = ocfs2_zero_extend(inode, zero_to);
+ if (ret < 0)
+ mlog_errno(ret);
+
+out:
+ return ret;
+}
+
static int ocfs2_extend_file(struct inode *inode,
struct buffer_head *di_bh,
- u64 new_i_size,
- size_t tail_to_skip)
+ u64 new_i_size)
{
int ret = 0;
- u32 clusters_to_add = 0;
- BUG_ON(!tail_to_skip && !di_bh);
+ BUG_ON(!di_bh);
/* setattr sometimes calls us like this. */
if (new_i_size == 0)
@@ -918,13 +921,8 @@ static int ocfs2_extend_file(struct inode *inode,
goto out;
BUG_ON(new_i_size < i_size_read(inode));
- if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
- BUG_ON(tail_to_skip != 0);
+ if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
goto out_update_size;
- }
-
- clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size) -
- OCFS2_I(inode)->ip_clusters;
/*
* protect the pages that ocfs2_zero_extend is going to be
@@ -939,35 +937,25 @@ static int ocfs2_extend_file(struct inode *inode,
goto out;
}
- if (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;
- }
- }
-
/*
- * Call this even if we don't add any clusters to the tree. We
- * still need to zero the area between the old i_size and the
- * new i_size.
+ * The alloc sem blocks people 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.
*/
- ret = ocfs2_zero_extend(inode, (u64)new_i_size - tail_to_skip);
+ down_write(&OCFS2_I(inode)->ip_alloc_sem);
+ ret = ocfs2_extend_no_holes(inode, new_i_size, new_i_size);
+ up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
if (ret < 0) {
mlog_errno(ret);
goto out_unlock;
}
out_update_size:
- if (!tail_to_skip) {
- /* We're being called from ocfs2_setattr() which wants
- * us to update i_size */
- ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
- if (ret < 0)
- mlog_errno(ret);
- }
+ ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
+ if (ret < 0)
+ mlog_errno(ret);
out_unlock:
if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
@@ -1036,7 +1024,7 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
if (i_size_read(inode) > attr->ia_size)
status = ocfs2_truncate_file(inode, bh, attr->ia_size);
else
- status = ocfs2_extend_file(inode, bh, attr->ia_size, 0);
+ status = ocfs2_extend_file(inode, bh, attr->ia_size);
if (status < 0) {
if (status != -ENOSPC)
mlog_errno(status);
@@ -1714,15 +1702,13 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
int appending,
int *direct_io)
{
- int ret = 0, meta_level = appending;
+ int ret = 0, meta_level = 0;
struct inode *inode = dentry->d_inode;
- u32 clusters;
- loff_t newsize, saved_pos;
+ loff_t saved_pos, end;
/*
- * We sample i_size under a read level meta lock to see if our write
- * is extending the file, if it is we back off and get a write level
- * meta lock.
+ * We start with a read level meta lock and only jump to an ex
+ * if we need to make modifications here.
*/
for(;;) {
ret = ocfs2_meta_lock(inode, NULL, meta_level);
@@ -1764,87 +1750,38 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
saved_pos = *ppos;
}
- if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
- loff_t end = saved_pos + count;
-
- /*
- * Skip the O_DIRECT checks if we don't need
- * them.
- */
- if (!direct_io || !(*direct_io))
- break;
-
- /*
- * Allowing concurrent direct writes means
- * i_size changes wouldn't be synchronized, so
- * one node could wind up truncating another
- * nodes writes.
- */
- if (end > i_size_read(inode)) {
- *direct_io = 0;
- break;
- }
+ end = saved_pos + count;
- /*
- * We don't fill holes during direct io, so
- * check for them here. If any are found, the
- * caller will have to retake some cluster
- * locks and initiate the io as buffered.
- */
- ret = ocfs2_check_range_for_holes(inode, saved_pos,
- count);
- if (ret == 1) {
- *direct_io = 0;
- ret = 0;
- } else if (ret < 0)
- mlog_errno(ret);
+ /*
+ * Skip the O_DIRECT checks if we don't need
+ * them.
+ */
+ if (!direct_io || !(*direct_io))
break;
- }
/*
- * The rest of this loop is concerned with legacy file
- * systems which don't support sparse files.
+ * Allowing concurrent direct writes means
+ * i_size changes wouldn't be synchronized, so
+ * one node could wind up truncating another
+ * nodes writes.
*/
-
- newsize = count + saved_pos;
-
- mlog(0, "pos=%lld newsize=%lld cursize=%lld\n",
- (long long) saved_pos, (long long) newsize,
- (long long) i_size_read(inode));
-
- /* No need for a higher level metadata lock if we're
- * never going past i_size. */
- if (newsize <= i_size_read(inode))
+ if (end > i_size_read(inode)) {
+ *direct_io = 0;
break;
-
- if (meta_level == 0) {
- ocfs2_meta_unlock(inode, meta_level);
- meta_level = 1;
- continue;
}
- spin_lock(&OCFS2_I(inode)->ip_lock);
- clusters = ocfs2_clusters_for_bytes(inode->i_sb, newsize) -
- OCFS2_I(inode)->ip_clusters;
- spin_unlock(&OCFS2_I(inode)->ip_lock);
-
- mlog(0, "Writing at EOF, may need more allocation: "
- "i_size = %lld, newsize = %lld, need %u clusters\n",
- (long long) i_size_read(inode), (long long) newsize,
- clusters);
-
- /* We only want to continue the rest of this loop if
- * our extend will actually require more
- * allocation. */
- if (!clusters)
- break;
-
- ret = ocfs2_extend_file(inode, NULL, newsize, count);
- if (ret < 0) {
- if (ret != -ENOSPC)
- mlog_errno(ret);
- goto out_unlock;
- }
+ /*
+ * We don't fill holes during direct io, so
+ * check for them here. If any are found, the
+ * caller will have to retake some cluster
+ * locks and initiate the io as buffered.
+ */
+ ret = ocfs2_check_range_for_holes(inode, saved_pos, count);
+ if (ret == 1) {
+ *direct_io = 0;
+ ret = 0;
+ } else if (ret < 0)
+ mlog_errno(ret);
break;
}
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index 36fe27f..066f14a 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -47,6 +47,8 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
struct ocfs2_alloc_context *data_ac,
struct ocfs2_alloc_context *meta_ac,
enum ocfs2_alloc_restarted *reason_ret);
+int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size,
+ u64 zero_to);
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,
--
1.5.0.6
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