* [PATCH] btrfs: use proper type for failrec in extent_state
@ 2016-02-11 12:24 David Sterba
2016-02-22 17:58 ` David Sterba
0 siblings, 1 reply; 4+ messages in thread
From: David Sterba @ 2016-02-11 12:24 UTC (permalink / raw)
To: linux-btrfs; +Cc: David Sterba
We use the private member of extent_state to store the failrec and play
pointless pointer games.
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/extent_io.c | 31 ++++++++++++++-----------------
fs/btrfs/extent_io.h | 5 ++---
2 files changed, 16 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2e7c97a3f344..f3910ac00d89 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -232,7 +232,7 @@ static struct extent_state *alloc_extent_state(gfp_t mask)
if (!state)
return state;
state->state = 0;
- state->private = 0;
+ state->failrec = NULL;
RB_CLEAR_NODE(&state->rb_node);
btrfs_leak_debug_add(&state->leak_list, &states);
atomic_set(&state->refs, 1);
@@ -1844,7 +1844,8 @@ out:
* set the private field for a given byte offset in the tree. If there isn't
* an extent_state there already, this does nothing.
*/
-static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private)
+static int set_state_failrec(struct extent_io_tree *tree, u64 start,
+ struct io_failure_record *failrec)
{
struct rb_node *node;
struct extent_state *state;
@@ -1865,13 +1866,14 @@ static int set_state_private(struct extent_io_tree *tree, u64 start, u64 private
ret = -ENOENT;
goto out;
}
- state->private = private;
+ state->failrec = failrec;
out:
spin_unlock(&tree->lock);
return ret;
}
-int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
+static int get_state_failrec(struct extent_io_tree *tree, u64 start,
+ struct io_failure_record **failrec)
{
struct rb_node *node;
struct extent_state *state;
@@ -1892,7 +1894,7 @@ int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private)
ret = -ENOENT;
goto out;
}
- *private = state->private;
+ *failrec = state->failrec;
out:
spin_unlock(&tree->lock);
return ret;
@@ -1972,7 +1974,7 @@ int free_io_failure(struct inode *inode, struct io_failure_record *rec)
int err = 0;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
- set_state_private(failure_tree, rec->start, 0);
+ set_state_failrec(failure_tree, rec->start, NULL);
ret = clear_extent_bits(failure_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
@@ -2089,7 +2091,6 @@ int clean_io_failure(struct inode *inode, u64 start, struct page *page,
unsigned int pg_offset)
{
u64 private;
- u64 private_failure;
struct io_failure_record *failrec;
struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
struct extent_state *state;
@@ -2102,12 +2103,11 @@ int clean_io_failure(struct inode *inode, u64 start, struct page *page,
if (!ret)
return 0;
- ret = get_state_private(&BTRFS_I(inode)->io_failure_tree, start,
- &private_failure);
+ ret = get_state_failrec(&BTRFS_I(inode)->io_failure_tree, start,
+ &failrec);
if (ret)
return 0;
- failrec = (struct io_failure_record *)(unsigned long) private_failure;
BUG_ON(!failrec->this_mirror);
if (failrec->in_validation) {
@@ -2167,7 +2167,7 @@ void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
next = next_state(state);
- failrec = (struct io_failure_record *)(unsigned long)state->private;
+ failrec = state->failrec;
free_extent_state(state);
kfree(failrec);
@@ -2177,10 +2177,9 @@ void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
}
int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
- struct io_failure_record **failrec_ret)
+ struct io_failure_record **failrec_ret)
{
struct io_failure_record *failrec;
- u64 private;
struct extent_map *em;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
@@ -2188,7 +2187,7 @@ int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
int ret;
u64 logical;
- ret = get_state_private(failure_tree, start, &private);
+ ret = get_state_failrec(failure_tree, start, &failrec);
if (ret) {
failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
if (!failrec)
@@ -2237,8 +2236,7 @@ int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
ret = set_extent_bits(failure_tree, start, end,
EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
if (ret >= 0)
- ret = set_state_private(failure_tree, start,
- (u64)(unsigned long)failrec);
+ ret = set_state_failrec(failure_tree, start, failrec);
/* set the bits in the inode's tree */
if (ret >= 0)
ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED,
@@ -2248,7 +2246,6 @@ int btrfs_get_io_failure_record(struct inode *inode, u64 start, u64 end,
return ret;
}
} else {
- failrec = (struct io_failure_record *)(unsigned long)private;
pr_debug("Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d\n",
failrec->logical, failrec->start, failrec->len,
failrec->in_validation);
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 0377413bd4b9..98a25a100674 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -62,6 +62,7 @@
struct extent_state;
struct btrfs_root;
struct btrfs_io_bio;
+struct io_failure_record;
typedef int (extent_submit_bio_hook_t)(struct inode *inode, int rw,
struct bio *bio, int mirror_num,
@@ -112,8 +113,7 @@ struct extent_state {
atomic_t refs;
unsigned state;
- /* for use by the FS */
- u64 private;
+ struct io_failure_record *failrec;
#ifdef CONFIG_BTRFS_DEBUG
struct list_head leak_list;
@@ -345,7 +345,6 @@ int extent_readpages(struct extent_io_tree *tree,
get_extent_t get_extent);
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len, get_extent_t *get_extent);
-int get_state_private(struct extent_io_tree *tree, u64 start, u64 *private);
void set_page_extent_mapped(struct page *page);
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
--
1.8.4.5
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] btrfs: use proper type for failrec in extent_state
2016-02-11 12:24 [PATCH] btrfs: use proper type for failrec in extent_state David Sterba
@ 2016-02-22 17:58 ` David Sterba
2016-02-23 2:06 ` Qu Wenruo
0 siblings, 1 reply; 4+ messages in thread
From: David Sterba @ 2016-02-22 17:58 UTC (permalink / raw)
To: David Sterba; +Cc: linux-btrfs
On Thu, Feb 11, 2016 at 01:24:13PM +0100, David Sterba wrote:
> We use the private member of extent_state to store the failrec and play
> pointless pointer games.
>
> Signed-off-by: David Sterba <dsterba@suse.com>
I'm not sure why, but my gcc 5.3.1 think's that a member of failrec can
be used uninitialized:
CC [M] fs/btrfs/extent_io.o
fs/btrfs/extent_io.c: In function ‘clean_io_failure’:
fs/btrfs/extent_io.c:2133:4: warning: ‘failrec’ may be used uninitialized in this function [-Wmaybe-uninitialized]
repair_io_failure(inode, start, failrec->len,
^
which points to:
2126 if (state && state->start <= failrec->start &&
2127 state->end >= failrec->start + failrec->len - 1) {
2128 num_copies = btrfs_num_copies(fs_info, failrec->logical,
2129 failrec->len);
2130 if (num_copies > 1) {
2131 repair_io_failure(inode, start, failrec->len,
2132 failrec->logical, page,
2133 pg_offset, failrec->failed_mirror);
2134 }
2135 }
After separating all members to local varaibles, it points to ->len. Which is
used several times in code above.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] btrfs: use proper type for failrec in extent_state
2016-02-22 17:58 ` David Sterba
@ 2016-02-23 2:06 ` Qu Wenruo
2016-02-23 11:34 ` David Sterba
0 siblings, 1 reply; 4+ messages in thread
From: Qu Wenruo @ 2016-02-23 2:06 UTC (permalink / raw)
To: dsterba, David Sterba, linux-btrfs
David Sterba wrote on 2016/02/22 18:58 +0100:
> On Thu, Feb 11, 2016 at 01:24:13PM +0100, David Sterba wrote:
>> We use the private member of extent_state to store the failrec and play
>> pointless pointer games.
>>
>> Signed-off-by: David Sterba <dsterba@suse.com>
>
> I'm not sure why, but my gcc 5.3.1 think's that a member of failrec can
> be used uninitialized:
>
> CC [M] fs/btrfs/extent_io.o
> fs/btrfs/extent_io.c: In function ‘clean_io_failure’:
> fs/btrfs/extent_io.c:2133:4: warning: ‘failrec’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> repair_io_failure(inode, start, failrec->len,
> ^
>
After applying your patch on integration-4.6, and compiling, my gcc
5.3.0 didn't give such warning though.
And I didn't see an official 5.3.1, but only 5.3 so I assume maybe it's
related to the .1 from your distribution?
(As my gcc is from Archlinux, I assume minimally patched)
Thanks,
Qu
> which points to:
>
> 2126 if (state && state->start <= failrec->start &&
> 2127 state->end >= failrec->start + failrec->len - 1) {
> 2128 num_copies = btrfs_num_copies(fs_info, failrec->logical,
> 2129 failrec->len);
> 2130 if (num_copies > 1) {
> 2131 repair_io_failure(inode, start, failrec->len,
> 2132 failrec->logical, page,
> 2133 pg_offset, failrec->failed_mirror);
> 2134 }
> 2135 }
>
> After separating all members to local varaibles, it points to ->len. Which is
> used several times in code above.
> --
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>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] btrfs: use proper type for failrec in extent_state
2016-02-23 2:06 ` Qu Wenruo
@ 2016-02-23 11:34 ` David Sterba
0 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2016-02-23 11:34 UTC (permalink / raw)
To: Qu Wenruo; +Cc: David Sterba, linux-btrfs
On Tue, Feb 23, 2016 at 10:06:59AM +0800, Qu Wenruo wrote:
> > I'm not sure why, but my gcc 5.3.1 think's that a member of failrec can
> > be used uninitialized:
> >
> > CC [M] fs/btrfs/extent_io.o
> > fs/btrfs/extent_io.c: In function ‘clean_io_failure’:
> > fs/btrfs/extent_io.c:2133:4: warning: ‘failrec’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> > repair_io_failure(inode, start, failrec->len,
> > ^
> >
> After applying your patch on integration-4.6, and compiling, my gcc
> 5.3.0 didn't give such warning though.
>
> And I didn't see an official 5.3.1, but only 5.3 so I assume maybe it's
> related to the .1 from your distribution?
Yes it's distro gcc 5.3 + patches. Arnd sent a patch to fix the warning.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-02-11 12:24 [PATCH] btrfs: use proper type for failrec in extent_state David Sterba
2016-02-22 17:58 ` David Sterba
2016-02-23 2:06 ` Qu Wenruo
2016-02-23 11:34 ` David Sterba
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