lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Btrfs: avoid sleeping in verify_parent_transid while atomic

Browse Source 
verify_parent_transid needs to lock the extent range to make
sure no IO is underway, and so it can safely clear the
uptodate bits if our checks fail.

But, a few callers are using it with spinlocks held.  Most
of the time, the generation numbers are going to match, and
we don't want to switch to a blocking lock just for the error
case.  This adds an atomic flag to verify_parent_transid,
and changes it to return EAGAIN if it needs to block to
properly verifiy things.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2012-05-06 07:23:47 -04:00
parent ea9947b439
commit b9fab919b7
5 changed files with 34 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
fs/btrfs/ctree.c
View File

@@ -725,7 +725,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
cur = btrfs_find_tree_block(root, blocknr, blocksize);
if (cur)
uptodate = btrfs_buffer_uptodate(cur, gen);
uptodate = btrfs_buffer_uptodate(cur, gen, 0);
else
uptodate = 0;
if (!cur || !uptodate) {
@@ -1360,7 +1360,12 @@ static noinline int reada_for_balance(struct btrfs_root *root,
block1 = btrfs_node_blockptr(parent, slot - 1);
gen = btrfs_node_ptr_generation(parent, slot - 1);
eb = btrfs_find_tree_block(root, block1, blocksize);
if (eb && btrfs_buffer_uptodate(eb, gen))
/*
* if we get -eagain from btrfs_buffer_uptodate, we
* don't want to return eagain here. That will loop
* forever
*/
if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
block1 = 0;
free_extent_buffer(eb);
}
@@ -1368,7 +1373,7 @@ static noinline int reada_for_balance(struct btrfs_root *root,
block2 = btrfs_node_blockptr(parent, slot + 1);
gen = btrfs_node_ptr_generation(parent, slot + 1);
eb = btrfs_find_tree_block(root, block2, blocksize);
if (eb && btrfs_buffer_uptodate(eb, gen))
if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
block2 = 0;
free_extent_buffer(eb);
}
@@ -1506,8 +1511,9 @@ read_block_for_search(struct btrfs_trans_handle *trans,
tmp = btrfs_find_tree_block(root, blocknr, blocksize);
if (tmp) {
if (btrfs_buffer_uptodate(tmp, 0)) {
if (btrfs_buffer_uptodate(tmp, gen)) {
/* first we do an atomic uptodate check */
if (btrfs_buffer_uptodate(tmp, 0, 1) > 0) {
if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
/*
* we found an up to date block without
* sleeping, return
@@ -1525,8 +1531,9 @@ read_block_for_search(struct btrfs_trans_handle *trans,
free_extent_buffer(tmp);
btrfs_set_path_blocking(p);
/* now we're allowed to do a blocking uptodate check */
tmp = read_tree_block(root, blocknr, blocksize, gen);
if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
if (tmp && btrfs_buffer_uptodate(tmp, gen, 0) > 0) {
*eb_ret = tmp;
return 0;
}
@@ -1561,7 +1568,7 @@ read_block_for_search(struct btrfs_trans_handle *trans,
* and give up so that our caller doesn't loop forever
* on our EAGAINs.
*/
if (!btrfs_buffer_uptodate(tmp, 0))
if (!btrfs_buffer_uptodate(tmp, 0, 0))
ret = -EIO;
free_extent_buffer(tmp);
}
@@ -4045,7 +4052,7 @@ again:
tmp = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
if (tmp && btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
free_extent_buffer(tmp);
break;
}
@@ -4168,7 +4175,8 @@ next:
struct extent_buffer *cur;
cur = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));
if (!cur || !btrfs_buffer_uptodate(cur, gen)) {
if (!cur ||
btrfs_buffer_uptodate(cur, gen, 1) <= 0) {
slot++;
if (cur)
free_extent_buffer(cur);