Re: [Tux3] Patch: Preliminary attempt at nospace handing
Here is a better patch that doesn't deadlock (the last one did) and
uses the more proper generic_sync_sb_inodes instead of freeze_bdev.
I used the make-many-files.c program that Marcin dug up somewhere on
the net to test this, making the partition 4 GB, which is a little
too small to hold all the files. This exercises the nospace handling
nicely.
Note: one thing that freeze_bdev does that generic_sync_sb_inodes does
not is prevent new writes during the flush. We will have to think
about how this is to be handled.
Daniel
diff -r a49705ea1c95 user/kernel/commit.c
--- a/user/kernel/commit.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/commit.c Wed Mar 04 03:26:33 2009 -0800
@@ -4,6 +4,7 @@
*/
#include tux3.h
+#include linux/writeback.h
#ifndef trace
#define trace trace_on
@@ -32,6 +33,8 @@
sb-atomgen = from_be_u32(super-atomgen);
sb-freeatom = from_be_u32(super-freeatom);
sb-dictsize = from_be_u64(super-dictsize);
+ sb-minchange = 8; /* total blocks changed by smallest change */
+ sb-margin = 100; // should be tunable?
trace(blocksize %u, blockbits %u, blockmask %08x,
sb-blocksize, sb-blockbits, sb-blockmask);
trace(volblocks %Lu, freeblocks %Lu, nextalloc %Lu,
@@ -236,6 +239,50 @@
return 0;
}
+int reserve_credits(struct sb *sb, unsigned credits)
+{
+ sb-credits += credits;
+ if (sb-margin 0 sb-freeblocks sb-credits + sb-margin) {
+#ifdef __KERNEL__
+ struct block_device *bdev = vfs_sb(sb)-s_bdev;
+ warn( %Lx free, %Lx credits, (L)sb-freeblocks, (L)sb-credits);
+ sb-margin = -sb-margin;
+ generic_sync_sb_inodes(vfs_sb(sb), (struct writeback_control){
+ .sync_mode = WB_SYNC_ALL,
+ .range_end = LLONG_MAX,
+ .nr_to_write = LONG_MAX });
+ sb-credits = 0;
+ thaw_bdev(bdev, vfs_sb(sb));
+ sb-margin = -sb-margin;
+#endif
+ warn( nospace = %i, sb-freeblocks sb-credits + sb-margin);
+ if (sb-freeblocks sb-credits + sb-margin) {
+ return -ENOSPC;
+ }
+ }
+ return 0;
+}
+
+void release_credits(struct sb *sb, unsigned credits)
+{
+ // try to return unused credits to pool //
+}
+
+int reserve_begin(struct sb *sb)
+{
+ int err;
+ if ((err = reserve_credits(sb, sb-minchange)))
+ return err;
+ return change_begin(sb);
+}
+
+int reduce_begin(struct sb *sb)
+{
+ int err;
+ if ((err = reserve_credits(sb, 0)))
+ return err;
+ return change_begin(sb);
+}
#ifdef __KERNEL__
static void *useme[] = { clean_buffer, need_delta, stage_delta, commit_delta, useme };
#endif
diff -r a49705ea1c95 user/kernel/dir.c
--- a/user/kernel/dir.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/dir.c Wed Mar 04 03:26:33 2009 -0800
@@ -132,7 +132,7 @@
while (entry = limit) {
if (entry-rec_len == 0) {
brelse(buffer);
-tux_error(dir-i_sb, zero-length directory entry);
+warn([CORRUPTION] Zero length directory record detected!);
return -EIO;
}
name_len = TUX_REC_LEN(entry-name_len);
diff -r a49705ea1c95 user/kernel/filemap.c
--- a/user/kernel/filemap.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/filemap.c Wed Mar 04 03:26:33 2009 -0800
@@ -511,7 +511,11 @@
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
+ struct sb *sb = tux_sb(mapping-host-i_sb);
+ int err;
*pagep = NULL;
+ if ((err = reserve_credits(sb, (len sb-blockbits) + 10)))
+ return err;
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
tux3_da_get_block);
}
@@ -519,8 +523,10 @@
static int tux3_writepage(struct page *page, struct writeback_control *wbc)
{
struct sb *sb = tux_sb(page-mapping-host-i_sb);
- change_begin(sb);
- int err = block_write_full_page(page, tux3_get_block, wbc);
+ int err = change_begin(sb);
+ if (err)
+ return err;
+ err = block_write_full_page(page, tux3_get_block, wbc);
change_end(sb);
return err;
}
diff -r a49705ea1c95 user/kernel/inode.c
--- a/user/kernel/inode.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/inode.c Wed Mar 04 03:26:33 2009 -0800
@@ -233,9 +233,10 @@
trace(save inode 0x%Lx, (L)tux_inode(inode)-inum);
struct sb *sb = tux_sb(inode-i_sb);
struct btree *itable = itable_btree(sb);
+ struct cursor *cursor;
int err;
- struct cursor *cursor = alloc_cursor(itable, 1); /* +1 for new depth */
- if (!cursor)
+
+ if (!(cursor = alloc_cursor(itable, 1))) /* +1 for new depth */
return -ENOMEM;
down_write(cursor-btree-lock);
if ((err = probe(cursor, tux_inode(inode)-inum)))
diff -r a49705ea1c95 user/kernel/namei.c
--- a/user/kernel/namei.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/namei.c Wed Mar 04 03:26:33 2009 -0800
@@ -60,13 +60,14 @@
static int tux3_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
{
+ struct sb *sb = tux_sb(dir-i_sb);
struct inode *inode;
int err;
if (!huge_valid_dev(rdev))
return -EINVAL;
-
- change_begin(tux_sb(dir-i_sb));
+ if ((err = reserve_begin(sb)))
+ return err;
inode = tux_create_inode(dir, mode, rdev);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
@@ -81,7 +82,7 @@
Re: [Tux3] Patch: Preliminary attempt at nospace handing
Another small adjustment to make rm -r work without failing on nospace.
Regards,
Daniel
diff -r a49705ea1c95 user/kernel/commit.c
--- a/user/kernel/commit.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/commit.c Wed Mar 04 18:17:05 2009 -0800
@@ -32,6 +32,8 @@ int load_sb(struct sb *sb)
sb-atomgen = from_be_u32(super-atomgen);
sb-freeatom = from_be_u32(super-freeatom);
sb-dictsize = from_be_u64(super-dictsize);
+ sb-minchange = 8; /* total blocks changed by smallest change */
+ sb-margin = 100; // should be tunable?
trace(blocksize %u, blockbits %u, blockmask %08x,
sb-blocksize, sb-blockbits, sb-blockmask);
trace(volblocks %Lu, freeblocks %Lu, nextalloc %Lu,
@@ -236,6 +238,50 @@ int change_end(struct sb *sb)
return 0;
}
+int reserve_credits(struct sb *sb, unsigned credits)
+{
+ sb-credits += credits;
+ if (sb-margin 0 sb-freeblocks sb-credits + sb-margin) {
+#ifdef __KERNEL__
+ struct block_device *bdev = vfs_sb(sb)-s_bdev;
+ warn( %Lx free, %Lx credits, (L)sb-freeblocks, (L)sb-credits);
+ sb-margin = -sb-margin;
+ generic_sync_sb_inodes(vfs_sb(sb), (struct writeback_control){
+ .sync_mode = WB_SYNC_ALL,
+ .range_end = LLONG_MAX,
+ .nr_to_write = LONG_MAX });
+ sb-credits = 0;
+ thaw_bdev(bdev, vfs_sb(sb));
+ sb-margin = -sb-margin;
+#endif
+ warn( nospace = %i, sb-freeblocks sb-credits + sb-margin);
+ if (sb-freeblocks sb-credits + sb-margin) {
+ return -ENOSPC;
+ }
+ }
+ return 0;
+}
+
+void release_credits(struct sb *sb, unsigned credits)
+{
+ // try to return unused credits to pool //
+}
+
+int reserve_begin(struct sb *sb)
+{
+ int err;
+ if ((err = reserve_credits(sb, sb-minchange)))
+ return err;
+ return change_begin(sb);
+}
+
+int reduce_begin(struct sb *sb)
+{
+// int err;
+// if ((err = reserve_credits(sb, 0)))
+// return err;
+ return change_begin(sb);
+}
#ifdef __KERNEL__
static void *useme[] = { clean_buffer, need_delta, stage_delta, commit_delta, useme };
#endif
diff -r a49705ea1c95 user/kernel/dir.c
--- a/user/kernel/dir.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/dir.c Wed Mar 04 18:17:05 2009 -0800
@@ -132,7 +132,7 @@ loff_t _tux_create_entry(struct inode *d
while (entry = limit) {
if (entry-rec_len == 0) {
brelse(buffer);
-tux_error(dir-i_sb, zero-length directory entry);
+warn([CORRUPTION] Zero length directory record detected!);
return -EIO;
}
name_len = TUX_REC_LEN(entry-name_len);
diff -r a49705ea1c95 user/kernel/filemap.c
--- a/user/kernel/filemap.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/filemap.c Wed Mar 04 18:17:05 2009 -0800
@@ -511,7 +511,11 @@ static int tux3_da_write_begin(struct fi
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
+ struct sb *sb = tux_sb(mapping-host-i_sb);
+ int err;
*pagep = NULL;
+ if ((err = reserve_credits(sb, (len sb-blockbits) + 10)))
+ return err;
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
tux3_da_get_block);
}
@@ -519,8 +523,10 @@ static int tux3_writepage(struct page *p
static int tux3_writepage(struct page *page, struct writeback_control *wbc)
{
struct sb *sb = tux_sb(page-mapping-host-i_sb);
- change_begin(sb);
- int err = block_write_full_page(page, tux3_get_block, wbc);
+ int err = change_begin(sb);
+ if (err)
+ return err;
+ err = block_write_full_page(page, tux3_get_block, wbc);
change_end(sb);
return err;
}
diff -r a49705ea1c95 user/kernel/inode.c
--- a/user/kernel/inode.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/inode.c Wed Mar 04 18:17:05 2009 -0800
@@ -233,9 +233,10 @@ static int save_inode(struct inode *inod
trace(save inode 0x%Lx, (L)tux_inode(inode)-inum);
struct sb *sb = tux_sb(inode-i_sb);
struct btree *itable = itable_btree(sb);
+ struct cursor *cursor;
int err;
- struct cursor *cursor = alloc_cursor(itable, 1); /* +1 for new depth */
- if (!cursor)
+
+ if (!(cursor = alloc_cursor(itable, 1))) /* +1 for new depth */
return -ENOMEM;
down_write(cursor-btree-lock);
if ((err = probe(cursor, tux_inode(inode)-inum)))
diff -r a49705ea1c95 user/kernel/namei.c
--- a/user/kernel/namei.c Tue Mar 03 20:43:11 2009 -0800
+++ b/user/kernel/namei.c Wed Mar 04 18:17:05 2009 -0800
@@ -60,13 +60,14 @@ static int tux_del_dirent(struct inode *
static int tux3_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
{
+ struct sb *sb = tux_sb(dir-i_sb);
struct inode *inode;
int err;
if (!huge_valid_dev(rdev))
return -EINVAL;
-
- change_begin(tux_sb(dir-i_sb));
+ if ((err = reserve_begin(sb)))
+ return err;
inode = tux_create_inode(dir, mode, rdev);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
@@ -81,7 +82,7 @@ static int tux3_mknod(struct inode *dir,
iput(inode);
}
out:
- change_end(tux_sb(dir-i_sb));
+ change_end(sb);
return err;
}
@@ -100,13 +101,14 @@ static int tux3_link(struct dentry *old_
static int tux3_link(struct dentry *old_dentry, struct inode *dir,
struct
