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authorQu Wenruo <wqu@suse.com>2020-12-22 13:59:24 +0800
committerDavid Sterba <dsterba@suse.com>2021-02-08 22:58:51 +0100
commit58f74b2203d786da37128cbf786873996145bfdc (patch)
treecef587f51564f454cfb89d3a2b6ff08c50d4a9cb /fs/btrfs/ordered-data.c
parent523929f1cac3e869492ea376c9d86af11ec0e5c5 (diff)
downloadlinux-58f74b2203d786da37128cbf786873996145bfdc.tar.bz2
btrfs: refactor btrfs_dec_test_* functions for ordered extents
The refactoring involves the following modifications: - Return bool instead of int - Parameter update for @cached of btrfs_dec_test_first_ordered_pending() For btrfs_dec_test_first_ordered_pending(), @cached is only used to return the finished ordered extent. Rename it to @finished_ret. - Comment updates * Change one stale comment Which still refers to btrfs_dec_test_ordered_pending(), but the context is calling btrfs_dec_test_first_ordered_pending(). * Follow the common comment style for both functions Add more detailed descriptions for parameters and the return value * Move the reason why test_and_set_bit() is used into the call sites - Change how the return value is calculated The most anti-human part of the return value is: if (...) ret = 1; ... return ret == 0; This means, when we set ret to 1, the function returns 0. Change the local variable name to @finished, and directly return the value of it. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/ordered-data.c')
-rw-r--r--fs/btrfs/ordered-data.c104
1 files changed, 58 insertions, 46 deletions
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 79d366a36223..d5d326c674b1 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -297,26 +297,33 @@ void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
}
/*
- * this is used to account for finished IO across a given range
- * of the file. The IO may span ordered extents. If
- * a given ordered_extent is completely done, 1 is returned, otherwise
- * 0.
+ * Finish IO for one ordered extent across a given range. The range can
+ * contain several ordered extents.
*
- * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
- * to make sure this function only returns 1 once for a given ordered extent.
+ * @found_ret: Return the finished ordered extent
+ * @file_offset: File offset for the finished IO
+ * Will also be updated to one byte past the range that is
+ * recordered as finished. This allows caller to walk forward.
+ * @io_size: Length of the finish IO range
+ * @uptodate: If the IO finished without problem
*
- * file_offset is updated to one byte past the range that is recorded as
- * complete. This allows you to walk forward in the file.
+ * Return true if any ordered extent is finished in the range, and update
+ * @found_ret and @file_offset.
+ * Return false otherwise.
+ *
+ * NOTE: Although The range can cross multiple ordered extents, only one
+ * ordered extent will be updated during one call. The caller is responsible to
+ * iterate all ordered extents in the range.
*/
-int btrfs_dec_test_first_ordered_pending(struct btrfs_inode *inode,
- struct btrfs_ordered_extent **cached,
+bool btrfs_dec_test_first_ordered_pending(struct btrfs_inode *inode,
+ struct btrfs_ordered_extent **finished_ret,
u64 *file_offset, u64 io_size, int uptodate)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
- int ret;
+ bool finished = false;
unsigned long flags;
u64 dec_end;
u64 dec_start;
@@ -324,16 +331,12 @@ int btrfs_dec_test_first_ordered_pending(struct btrfs_inode *inode,
spin_lock_irqsave(&tree->lock, flags);
node = tree_search(tree, *file_offset);
- if (!node) {
- ret = 1;
+ if (!node)
goto out;
- }
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
- if (!offset_in_entry(entry, *file_offset)) {
- ret = 1;
+ if (!offset_in_entry(entry, *file_offset))
goto out;
- }
dec_start = max(*file_offset, entry->file_offset);
dec_end = min(*file_offset + io_size,
@@ -354,39 +357,50 @@ int btrfs_dec_test_first_ordered_pending(struct btrfs_inode *inode,
set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
if (entry->bytes_left == 0) {
- ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+ /*
+ * Ensure only one caller can set the flag and finished_ret
+ * accordingly
+ */
+ finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
/* test_and_set_bit implies a barrier */
cond_wake_up_nomb(&entry->wait);
- } else {
- ret = 1;
}
out:
- if (!ret && cached && entry) {
- *cached = entry;
+ if (finished && finished_ret && entry) {
+ *finished_ret = entry;
refcount_inc(&entry->refs);
}
spin_unlock_irqrestore(&tree->lock, flags);
- return ret == 0;
+ return finished;
}
/*
- * this is used to account for finished IO across a given range
- * of the file. The IO should not span ordered extents. If
- * a given ordered_extent is completely done, 1 is returned, otherwise
- * 0.
+ * Finish IO for one ordered extent across a given range. The range can only
+ * contain one ordered extent.
+ *
+ * @cached: The cached ordered extent. If not NULL, we can skip the tree
+ * search and use the ordered extent directly.
+ * Will be also used to store the finished ordered extent.
+ * @file_offset: File offset for the finished IO
+ * @io_size: Length of the finish IO range
+ * @uptodate: If the IO finishes without problem
+ *
+ * Return true if the ordered extent is finished in the range, and update
+ * @cached.
+ * Return false otherwise.
*
- * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
- * to make sure this function only returns 1 once for a given ordered extent.
+ * NOTE: The range can NOT cross multiple ordered extents.
+ * Thus caller should ensure the range doesn't cross ordered extents.
*/
-int btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
- struct btrfs_ordered_extent **cached,
- u64 file_offset, u64 io_size, int uptodate)
+bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
+ struct btrfs_ordered_extent **cached,
+ u64 file_offset, u64 io_size, int uptodate)
{
struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
unsigned long flags;
- int ret;
+ bool finished = false;
spin_lock_irqsave(&tree->lock, flags);
if (cached && *cached) {
@@ -395,41 +409,39 @@ int btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
}
node = tree_search(tree, file_offset);
- if (!node) {
- ret = 1;
+ if (!node)
goto out;
- }
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
have_entry:
- if (!offset_in_entry(entry, file_offset)) {
- ret = 1;
+ if (!offset_in_entry(entry, file_offset))
goto out;
- }
- if (io_size > entry->bytes_left) {
+ if (io_size > entry->bytes_left)
btrfs_crit(inode->root->fs_info,
"bad ordered accounting left %llu size %llu",
entry->bytes_left, io_size);
- }
+
entry->bytes_left -= io_size;
if (!uptodate)
set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
if (entry->bytes_left == 0) {
- ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+ /*
+ * Ensure only one caller can set the flag and finished_ret
+ * accordingly
+ */
+ finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
/* test_and_set_bit implies a barrier */
cond_wake_up_nomb(&entry->wait);
- } else {
- ret = 1;
}
out:
- if (!ret && cached && entry) {
+ if (finished && cached && entry) {
*cached = entry;
refcount_inc(&entry->refs);
}
spin_unlock_irqrestore(&tree->lock, flags);
- return ret == 0;
+ return finished;
}
/*