Andrew,
I'm providing a patch that puts the test in some more or less trivial
cases.
Maybe putting them in -mm tree could give them the test environment they
need.
But even if the patch gets in, there are still some cases that I don't
feel comfortable with right now to fix.
On Mon, Oct 10, 2005 at 04:36:48PM -0700, Andrew Morton wrote:
> Anton Altaparmakov <[email protected]> wrote:
> >
> > > Maybe the best solution is neither one nor another. Testing and failing
> > > gracefully seems better.
> > >
> > > What do you think?
> >
> > I certainly agree with you there. I neither want a deadlock nor
> > corruption. (-:
>
> Yup. In the present implementation __getblk_slow() "cannot fail". It's
> conceivable that at some future stage we'll change __getblk_slow() so that
> it returns NULL on an out-of-memory condition. Anyone making such a change
> would have to audit all callers to make sure that they handle the NULL
> correctly.
>
> It is appropriate at this time to fix the callers so that they correctly
> handle the NULL return. However, it is non-trivial to actually _test_ such
> changes, and such changes should be tested. Or at least, they should be
> done with considerable care and knowledge of the specific filesystems.
>
--
=====================================
Glauber de Oliveira Costa
IBM Linux Technology Center - Brazil
[email protected]
=====================================
diff -Naurp linux-2.6.14-rc2-orig/fs/affs/affs.h linux-2.6.14-rc2-cleanp/fs/affs/affs.h
--- linux-2.6.14-rc2-orig/fs/affs/affs.h 2005-06-17 19:48:29.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/affs/affs.h 2005-10-10 22:28:30.000000000 +0000
@@ -230,6 +230,8 @@ affs_getzeroblk(struct super_block *sb,
pr_debug("affs_getzeroblk: %d\n", block);
if (block >= AFFS_SB(sb)->s_reserved && block < AFFS_SB(sb)->s_partition_size) {
bh = sb_getblk(sb, block);
+ if (!bh)
+ return NULL;
lock_buffer(bh);
memset(bh->b_data, 0 , sb->s_blocksize);
set_buffer_uptodate(bh);
@@ -245,6 +247,8 @@ affs_getemptyblk(struct super_block *sb,
pr_debug("affs_getemptyblk: %d\n", block);
if (block >= AFFS_SB(sb)->s_reserved && block < AFFS_SB(sb)->s_partition_size) {
bh = sb_getblk(sb, block);
+ if (!bh)
+ return NULL;
wait_on_buffer(bh);
set_buffer_uptodate(bh);
return bh;
diff -Naurp linux-2.6.14-rc2-orig/fs/bfs/file.c linux-2.6.14-rc2-cleanp/fs/bfs/file.c
--- linux-2.6.14-rc2-orig/fs/bfs/file.c 2005-09-26 13:58:15.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/bfs/file.c 2005-10-10 21:58:23.000000000 +0000
@@ -33,6 +33,8 @@ static int bfs_move_block(unsigned long
if (!bh)
return -EIO;
new = sb_getblk(sb, to);
+ if (!new)
+ return -EIO;
memcpy(new->b_data, bh->b_data, bh->b_size);
mark_buffer_dirty(new);
bforget(bh);
diff -Naurp linux-2.6.14-rc2-orig/fs/ext2/inode.c linux-2.6.14-rc2-cleanp/fs/ext2/inode.c
--- linux-2.6.14-rc2-orig/fs/ext2/inode.c 2005-09-26 13:58:15.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/ext2/inode.c 2005-10-10 22:31:12.000000000 +0000
@@ -440,6 +440,8 @@ static int ext2_alloc_branch(struct inod
* the pointer to new one, then send parent to disk.
*/
bh = sb_getblk(inode->i_sb, parent);
+ if (!bh)
+ break;
lock_buffer(bh);
memset(bh->b_data, 0, blocksize);
branch[n].bh = bh;
diff -Naurp linux-2.6.14-rc2-orig/fs/ext3/inode.c linux-2.6.14-rc2-cleanp/fs/ext3/inode.c
--- linux-2.6.14-rc2-orig/fs/ext3/inode.c 2005-10-09 20:26:54.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/ext3/inode.c 2005-10-10 22:38:05.000000000 +0000
@@ -532,6 +532,8 @@ static int ext3_alloc_branch(handle_t *h
*/
bh = sb_getblk(inode->i_sb, parent);
branch[n].bh = bh;
+ if (!bh)
+ break;
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
err = ext3_journal_get_create_access(handle, bh);
@@ -864,7 +866,7 @@ struct buffer_head *ext3_getblk(handle_t
if (!*errp && buffer_mapped(&dummy)) {
struct buffer_head *bh;
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
- if (buffer_new(&dummy)) {
+ if (bh && buffer_new(&dummy)) {
J_ASSERT(create != 0);
J_ASSERT(handle != 0);
diff -Naurp linux-2.6.14-rc2-orig/fs/minix/itree_common.c linux-2.6.14-rc2-cleanp/fs/minix/itree_common.c
--- linux-2.6.14-rc2-orig/fs/minix/itree_common.c 2005-06-17 19:48:29.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/minix/itree_common.c 2005-10-10 22:59:31.000000000 +0000
@@ -84,6 +84,8 @@ static int alloc_branch(struct inode *in
break;
branch[n].key = cpu_to_block(nr);
bh = sb_getblk(inode->i_sb, parent);
+ if (!bh)
+ break;
lock_buffer(bh);
memset(bh->b_data, 0, BLOCK_SIZE);
branch[n].bh = bh;
diff -Naurp linux-2.6.14-rc2-orig/fs/reiserfs/journal.c linux-2.6.14-rc2-cleanp/fs/reiserfs/journal.c
--- linux-2.6.14-rc2-orig/fs/reiserfs/journal.c 2005-09-26 13:58:16.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/reiserfs/journal.c 2005-10-10 22:44:31.000000000 +0000
@@ -2120,7 +2120,7 @@ static int journal_read_transaction(stru
le32_to_cpu(commit->
j_realblock[i - trans_half]));
}
- if (real_blocks[i]->b_blocknr > SB_BLOCK_COUNT(p_s_sb)) {
+ if (real_blocks[i] && real_blocks[i]->b_blocknr > SB_BLOCK_COUNT(p_s_sb)) {
reiserfs_warning(p_s_sb,
"journal-1207: REPLAY FAILURE fsck required! Block to replay is outside of filesystem");
goto abort_replay;
diff -Naurp linux-2.6.14-rc2-orig/fs/reiserfs/stree.c linux-2.6.14-rc2-cleanp/fs/reiserfs/stree.c
--- linux-2.6.14-rc2-orig/fs/reiserfs/stree.c 2005-09-01 14:26:04.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/reiserfs/stree.c 2005-10-10 22:56:14.000000000 +0000
@@ -664,7 +664,7 @@ int search_by_key(struct super_block *p_
have a pointer to it. */
if ((p_s_bh = p_s_last_element->pe_buffer =
sb_getblk(p_s_sb, n_block_number))) {
- if (!buffer_uptodate(p_s_bh) && reada_count > 1) {
+ if (p_s_sb && !buffer_uptodate(p_s_bh) && reada_count > 1) {
search_by_key_reada(p_s_sb, reada_bh,
reada_blocks, reada_count);
}
diff -Naurp linux-2.6.14-rc2-orig/fs/sysv/itree.c linux-2.6.14-rc2-cleanp/fs/sysv/itree.c
--- linux-2.6.14-rc2-orig/fs/sysv/itree.c 2005-06-17 19:48:29.000000000 +0000
+++ linux-2.6.14-rc2-cleanp/fs/sysv/itree.c 2005-10-10 22:41:35.000000000 +0000
@@ -144,6 +144,8 @@ static int alloc_branch(struct inode *in
*/
parent = block_to_cpu(SYSV_SB(inode->i_sb), branch[n-1].key);
bh = sb_getblk(inode->i_sb, parent);
+ if (!bh)
+ break;
lock_buffer(bh);
memset(bh->b_data, 0, blocksize);
branch[n].bh = bh;
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