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Btrfs: Remove broken optimisations in end_bio functions.
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These ended up freeing objects while they were still using them. Under
guidance from Chris, just rip out the 'clever' bits and do things the
simple way.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
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David Woodhouse authored and Chris Mason committed Sep 25, 2008
1 parent 5386323 commit 902b22f
Showing 1 changed file with 21 additions and 138 deletions.
159 changes: 21 additions & 138 deletions fs/btrfs/extent_io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@
#include "extent_io.h"
#include "extent_map.h"
#include "compat.h"
#include "ctree.h"
#include "btrfs_inode.h"

/* temporary define until extent_map moves out of btrfs */
struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
Expand Down Expand Up @@ -1394,22 +1396,20 @@ static int end_bio_extent_writepage(struct bio *bio,
{
int uptodate = err == 0;
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_state *state = bio->bi_private;
struct extent_io_tree *tree = state->tree;
struct rb_node *node;
struct extent_io_tree *tree;
u64 start;
u64 end;
u64 cur;
int whole_page;
int ret;
unsigned long flags;

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
if (bio->bi_size)
return 1;
#endif
do {
struct page *page = bvec->bv_page;
tree = &BTRFS_I(page->mapping->host)->io_tree;

start = ((u64)page->index << PAGE_CACHE_SHIFT) +
bvec->bv_offset;
end = start + bvec->bv_len - 1;
Expand All @@ -1423,17 +1423,16 @@ static int end_bio_extent_writepage(struct bio *bio,
prefetchw(&bvec->bv_page->flags);
if (tree->ops && tree->ops->writepage_end_io_hook) {
ret = tree->ops->writepage_end_io_hook(page, start,
end, state, uptodate);
end, NULL, uptodate);
if (ret)
uptodate = 0;
}

if (!uptodate && tree->ops &&
tree->ops->writepage_io_failed_hook) {
ret = tree->ops->writepage_io_failed_hook(bio, page,
start, end, state);
start, end, NULL);
if (ret == 0) {
state = NULL;
uptodate = (err == 0);
continue;
}
Expand All @@ -1445,68 +1444,7 @@ static int end_bio_extent_writepage(struct bio *bio,
SetPageError(page);
}

/*
* bios can get merged in funny ways, and so we need to
* be careful with the state variable. We know the
* state won't be merged with others because it has
* WRITEBACK set, but we can't be sure each biovec is
* sequential in the file. So, if our cached state
* doesn't match the expected end, search the tree
* for the correct one.
*/

spin_lock_irqsave(&tree->lock, flags);
if (!state || state->end != end) {
state = NULL;
node = __etree_search(tree, start, NULL, NULL);
if (node) {
state = rb_entry(node, struct extent_state,
rb_node);
if (state->end != end ||
!(state->state & EXTENT_WRITEBACK))
state = NULL;
}
if (!state) {
spin_unlock_irqrestore(&tree->lock, flags);
clear_extent_writeback(tree, start,
end, GFP_ATOMIC);
goto next_io;
}
}
cur = end;
while(1) {
struct extent_state *clear = state;
cur = state->start;
node = rb_prev(&state->rb_node);
if (node) {
state = rb_entry(node,
struct extent_state,
rb_node);
} else {
state = NULL;
}

clear_state_bit(tree, clear, EXTENT_WRITEBACK,
1, 0);
if (cur == start)
break;
if (cur < start) {
WARN_ON(1);
break;
}
if (!node)
break;
}
/* before releasing the lock, make sure the next state
* variable has the expected bits set and corresponds
* to the correct offsets in the file
*/
if (state && (state->end + 1 != start ||
!(state->state & EXTENT_WRITEBACK))) {
state = NULL;
}
spin_unlock_irqrestore(&tree->lock, flags);
next_io:
clear_extent_writeback(tree, start, end, GFP_ATOMIC);

if (whole_page)
end_page_writeback(page);
Expand Down Expand Up @@ -1539,13 +1477,9 @@ static int end_bio_extent_readpage(struct bio *bio,
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_state *state = bio->bi_private;
struct extent_io_tree *tree = state->tree;
struct rb_node *node;
struct extent_io_tree *tree;
u64 start;
u64 end;
u64 cur;
unsigned long flags;
int whole_page;
int ret;

Expand All @@ -1556,6 +1490,8 @@ static int end_bio_extent_readpage(struct bio *bio,

do {
struct page *page = bvec->bv_page;
tree = &BTRFS_I(page->mapping->host)->io_tree;

start = ((u64)page->index << PAGE_CACHE_SHIFT) +
bvec->bv_offset;
end = start + bvec->bv_len - 1;
Expand All @@ -1570,80 +1506,26 @@ static int end_bio_extent_readpage(struct bio *bio,

if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
ret = tree->ops->readpage_end_io_hook(page, start, end,
state);
NULL);
if (ret)
uptodate = 0;
}
if (!uptodate && tree->ops &&
tree->ops->readpage_io_failed_hook) {
ret = tree->ops->readpage_io_failed_hook(bio, page,
start, end, state);
start, end, NULL);
if (ret == 0) {
state = NULL;
uptodate =
test_bit(BIO_UPTODATE, &bio->bi_flags);
continue;
}
}

spin_lock_irqsave(&tree->lock, flags);
if (!state || state->end != end) {
state = NULL;
node = __etree_search(tree, start, NULL, NULL);
if (node) {
state = rb_entry(node, struct extent_state,
rb_node);
if (state->end != end ||
!(state->state & EXTENT_LOCKED))
state = NULL;
}
if (!state) {
spin_unlock_irqrestore(&tree->lock, flags);
if (uptodate)
set_extent_uptodate(tree, start, end,
GFP_ATOMIC);
unlock_extent(tree, start, end, GFP_ATOMIC);
goto next_io;
}
}
if (uptodate)
set_extent_uptodate(tree, start, end,
GFP_ATOMIC);
unlock_extent(tree, start, end, GFP_ATOMIC);

cur = end;
while(1) {
struct extent_state *clear = state;
cur = state->start;
node = rb_prev(&state->rb_node);
if (node) {
state = rb_entry(node,
struct extent_state,
rb_node);
} else {
state = NULL;
}
if (uptodate) {
set_state_cb(tree, clear, EXTENT_UPTODATE);
clear->state |= EXTENT_UPTODATE;
}
clear_state_bit(tree, clear, EXTENT_LOCKED,
1, 0);
if (cur == start)
break;
if (cur < start) {
WARN_ON(1);
break;
}
if (!node)
break;
}
/* before releasing the lock, make sure the next state
* variable has the expected bits set and corresponds
* to the correct offsets in the file
*/
if (state && (state->end + 1 != start ||
!(state->state & EXTENT_LOCKED))) {
state = NULL;
}
spin_unlock_irqrestore(&tree->lock, flags);
next_io:
if (whole_page) {
if (uptodate) {
SetPageUptodate(page);
Expand Down Expand Up @@ -1683,8 +1565,7 @@ static int end_bio_extent_preparewrite(struct bio *bio,
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
struct extent_state *state = bio->bi_private;
struct extent_io_tree *tree = state->tree;
struct extent_io_tree *tree;
u64 start;
u64 end;

Expand All @@ -1695,6 +1576,8 @@ static int end_bio_extent_preparewrite(struct bio *bio,

do {
struct page *page = bvec->bv_page;
tree = &BTRFS_I(page->mapping->host)->io_tree;

start = ((u64)page->index << PAGE_CACHE_SHIFT) +
bvec->bv_offset;
end = start + bvec->bv_len - 1;
Expand Down Expand Up @@ -1765,7 +1648,7 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num)
BUG_ON(state->end != end);
spin_unlock_irq(&tree->lock);

bio->bi_private = state;
bio->bi_private = NULL;

bio_get(bio);

Expand Down

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