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authorMiles Bader <miles@gnu.org>1995-04-27 03:02:00 +0000
committerMiles Bader <miles@gnu.org>1995-04-27 03:02:00 +0000
commit312731a709958bf10ab58556ae019e1eb896ab40 (patch)
tree62d222d98c971926a19a97d284a329f1a1fb7d9b
parenta6b50b45309449184680c44021fe91d3c1823139 (diff)
Formerly pager.c.~22~
-rw-r--r--ext2fs/pager.c111
1 files changed, 84 insertions, 27 deletions
diff --git a/ext2fs/pager.c b/ext2fs/pager.c
index c34f8cb1..bd7c1062 100644
--- a/ext2fs/pager.c
+++ b/ext2fs/pager.c
@@ -382,7 +382,9 @@ pager_write_page (struct user_pager_info *pager, vm_offset_t page,
/* ---------------------------------------------------------------- */
-/* Make page PAGE writable. */
+/* Make page PAGE writable, at least up to ALLOCSIZE. This function and
+ diskfs_grow are the only places that blocks are actually added to the
+ file. */
error_t
pager_unlock_page (struct user_pager_info *pager, vm_offset_t page)
{
@@ -391,7 +393,6 @@ pager_unlock_page (struct user_pager_info *pager, vm_offset_t page)
else
{
error_t err;
- char *buf;
daddr_t block = page >> log2_block_size;
struct node *node = pager->node;
struct disknode *dn = node->dn;
@@ -402,8 +403,18 @@ pager_unlock_page (struct user_pager_info *pager, vm_offset_t page)
if (!err)
{
int left = vm_page_size;
+
+ if (page + left > node->allocsize)
+ /* Only actually create blocks up to allocsize; diskfs_grow will
+ allocate the rest if called. */
+ {
+ left = node->allocsize - page;
+ dn->last_page_partially_writable = 1;
+ }
+
while (left > 0)
{
+ char *buf;
err = ext2_getblk(node, block++, 1, &buf);
if (err)
break;
@@ -430,10 +441,80 @@ diskfs_grow (struct node *node, off_t size, struct protid *cred)
assert (!diskfs_readonly);
if (size > node->allocsize)
- node->allocsize = trunc_block (size) + block_size;
+ {
+ error_t err;
+ struct disknode *dn = node->dn;
+ vm_offset_t old_size = node->allocsize;
+ vm_offset_t new_size = trunc_block (size) + block_size;
+
+ rwlock_writer_lock (&dn->alloc_lock);
+ err = diskfs_catch_exception ();
+
+ if (!err)
+ {
+ if (dn->last_page_partially_writable)
+ /* pager_unlock_page has been called on the last page of the
+ file, but only part of the page was created, as the rest went
+ past the end of the file. As a result, we have to create the
+ rest of the page to preserve the fact that blocks are only
+ created by explicitly making them writable. */
+ {
+ daddr_t block = old_size >> log2_block_size;
+ int count = trunc_page (old_size) + vm_page_size - old_size;
+
+ if (old_size + count > new_size)
+ count = new_size - old_size;
+ else
+ /* This will take care the whole page. */
+ dn->last_page_partially_writable = 0;
+
+ while (count > 0)
+ {
+ char *buf;
+ err = ext2_getblk(node, block++, 1, &buf);
+ if (err)
+ break;
+ count -= block_size;
+ }
+ }
+ }
+
+ diskfs_end_catch_exception ();
+ rwlock_writer_unlock (&dn->alloc_lock);
+
+ return err;
+ }
else
return 0;
}
+
+/* ---------------------------------------------------------------- */
+
+/* This syncs a single file (NODE) to disk. Wait for all I/O to complete
+ if WAIT is set. NODE->lock must be held. */
+void
+diskfs_file_update (struct node *node, int wait)
+{
+ struct user_pager_info *upi;
+
+ spin_lock (&node_to_page_lock);
+ upi = node->dn->fileinfo;
+ if (upi)
+ pager_reference (upi->p);
+ spin_unlock (&node_to_page_lock);
+
+ if (upi)
+ {
+ pager_sync (upi->p, wait);
+ pager_unreference (upi->p);
+ }
+
+ pokel_sync (&node->dn->indir_pokel, wait);
+
+ diskfs_node_update (node, wait);
+}
+
+/* ---------------------------------------------------------------- */
/* Implement the pager_report_extent callback from the pager library. See
<hurd/pager.h> for the interface description. */
@@ -524,30 +605,6 @@ diskfs_get_filemap (struct node *node)
return right;
}
-/* This syncs a single file (NODE) to disk. Wait for all I/O to complete
- if WAIT is set. NODE->lock must be held. */
-void
-diskfs_file_update (struct node *node, int wait)
-{
- struct user_pager_info *upi;
-
- spin_lock (&node_to_page_lock);
- upi = node->dn->fileinfo;
- if (upi)
- pager_reference (upi->p);
- spin_unlock (&node_to_page_lock);
-
- if (upi)
- {
- pager_sync (upi->p, wait);
- pager_unreference (upi->p);
- }
-
- pokel_sync (&node->dn->pokel, wait);
-
- diskfs_node_update (node, wait);
-}
-
/* Call this when we should turn off caching so that unused memory object
ports get freed. */
void