| Message ID | 20230324023207.544800-2-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/11] btrfs: add function to create and return an ordered extent | expand |
On Fri, Mar 24, 2023 at 10:31:57AM +0800, Christoph Hellwig wrote: > From: Boris Burkov <boris@bur.io> > > Currently, btrfs_add_ordered_extent allocates a new ordered extent, adds > it to the rb_tree, but doesn't return a referenced pointer to the > caller. There are cases where it is useful for the creator of a new > ordered_extent to hang on to such a pointer, so add a new function > btrfs_alloc_ordered_extent which is the same as > btrfs_add_ordered_extent, except it takes an additional reference count > and returns a pointer to the ordered_extent. Implement > btrfs_add_ordered_extent as btrfs_alloc_ordered_extent followed by > dropping the new reference and handling the IS_ERR case. > > The type of flags in btrfs_alloc_ordered_extent and > btrfs_add_ordered_extent is changed from unsigned int to unsigned long > so it's unified with the other ordered extent functions. > > Reviewed-by: Filipe Manana <fdmanana@suse.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Signed-off-by: Boris Burkov <boris@bur.io> > Signed-off-by: David Sterba <dsterba@suse.com> > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/btrfs/ordered-data.c | 46 +++++++++++++++++++++++++++++++++-------- > fs/btrfs/ordered-data.h | 5 +++++ > 2 files changed, 42 insertions(+), 9 deletions(-) > > diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c > index 6c24b69e2d0a37..83a51c692406ab 100644 > --- a/fs/btrfs/ordered-data.c > +++ b/fs/btrfs/ordered-data.c > @@ -160,14 +160,16 @@ static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree, > * @compress_type: Compression algorithm used for data. > * > * Most of these parameters correspond to &struct btrfs_file_extent_item. The > - * tree is given a single reference on the ordered extent that was inserted. > + * tree is given a single reference on the ordered extent that was inserted, and > + * the returned pointer is given a second reference. > * > - * Return: 0 or -ENOMEM. > + * Return: the new ordered extent or ERR_PTR(-ENOMEM). > */ > -int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, > - u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, > - u64 disk_num_bytes, u64 offset, unsigned flags, > - int compress_type) > +struct btrfs_ordered_extent *btrfs_alloc_ordered_extent( > + struct btrfs_inode *inode, u64 file_offset, > + u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, > + u64 disk_num_bytes, u64 offset, unsigned long flags, > + int compress_type) I'm sorry to write a comment on this late, but isn't the function name confusing? As I suggested a function only to allocate and initialize a btrfs_ordered_extent in the previous mail [1], I first thought this function is something like that. [1] https://lore.kernel.org/linux-btrfs/20230323083608.m2ut2whbk2smjjpu@naota-xeon/ But, both btrfs_alloc_ordered_extent() and btrfs_add_ordered_extent() "add an ordered extent to the per-inode tree." The difference is that btrfs_alloc_ordered_extent() returns the created ordered extent to the caller taking a reference for them... However, I can't think of a different name, so it might be OK... Other than that, Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com> > { > struct btrfs_root *root = inode->root; > struct btrfs_fs_info *fs_info = root->fs_info; > @@ -181,7 +183,7 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, > /* For nocow write, we can release the qgroup rsv right now */ > ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes); > if (ret < 0) > - return ret; > + return ERR_PTR(ret); > ret = 0; > } else { > /* > @@ -190,11 +192,11 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, > */ > ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes); > if (ret < 0) > - return ret; > + return ERR_PTR(ret); > } > entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS); > if (!entry) > - return -ENOMEM; > + return ERR_PTR(-ENOMEM); > > entry->file_offset = file_offset; > entry->num_bytes = num_bytes; > @@ -256,6 +258,32 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, > btrfs_mod_outstanding_extents(inode, 1); > spin_unlock(&inode->lock); > > + /* One ref for the returned entry to match semantics of lookup. */ > + refcount_inc(&entry->refs); > + > + return entry; > +} > + > +/* > + * Add a new btrfs_ordered_extent for the range, but drop the reference instead > + * of returning it to the caller. > + */ > +int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, > + u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, > + u64 disk_num_bytes, u64 offset, unsigned flags, > + int compress_type) > +{ > + struct btrfs_ordered_extent *ordered; > + > + ordered = btrfs_alloc_ordered_extent(inode, file_offset, num_bytes, > + ram_bytes, disk_bytenr, > + disk_num_bytes, offset, flags, > + compress_type); > + > + if (IS_ERR(ordered)) > + return PTR_ERR(ordered); > + btrfs_put_ordered_extent(ordered); > + > return 0; > } > > diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h > index eb40cb39f842e6..c00a5a3f060fa2 100644 > --- a/fs/btrfs/ordered-data.h > +++ b/fs/btrfs/ordered-data.h > @@ -178,6 +178,11 @@ void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode, > bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode, > struct btrfs_ordered_extent **cached, > u64 file_offset, u64 io_size); > +struct btrfs_ordered_extent *btrfs_alloc_ordered_extent( > + struct btrfs_inode *inode, u64 file_offset, > + u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, > + u64 disk_num_bytes, u64 offset, unsigned long flags, > + int compress_type); > int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, > u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, > u64 disk_num_bytes, u64 offset, unsigned flags, > -- > 2.39.2 >
On Fri, Mar 24, 2023 at 05:47:18AM +0000, Naohiro Aota wrote: > I'm sorry to write a comment on this late, but isn't the function name > confusing? As I suggested a function only to allocate and initialize a > btrfs_ordered_extent in the previous mail [1], I first thought this > function is something like that. > > [1] https://lore.kernel.org/linux-btrfs/20230323083608.m2ut2whbk2smjjpu@naota-xeon/ > > But, both btrfs_alloc_ordered_extent() and btrfs_add_ordered_extent() "add > an ordered extent to the per-inode tree." The difference is that > btrfs_alloc_ordered_extent() returns the created ordered extent to the > caller taking a reference for them... > > However, I can't think of a different name, so it might be OK... I can't really think of a better name either. That being said, splitting out the accounting and having a version that doesn't do it would be really useful for the split case. And in the very long run I hope I can kill off the ordered_extent tree entirely, but that's just futurism for now :)
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index 6c24b69e2d0a37..83a51c692406ab 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -160,14 +160,16 @@ static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree, * @compress_type: Compression algorithm used for data. * * Most of these parameters correspond to &struct btrfs_file_extent_item. The - * tree is given a single reference on the ordered extent that was inserted. + * tree is given a single reference on the ordered extent that was inserted, and + * the returned pointer is given a second reference. * - * Return: 0 or -ENOMEM. + * Return: the new ordered extent or ERR_PTR(-ENOMEM). */ -int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, - u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, - u64 disk_num_bytes, u64 offset, unsigned flags, - int compress_type) +struct btrfs_ordered_extent *btrfs_alloc_ordered_extent( + struct btrfs_inode *inode, u64 file_offset, + u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, + u64 disk_num_bytes, u64 offset, unsigned long flags, + int compress_type) { struct btrfs_root *root = inode->root; struct btrfs_fs_info *fs_info = root->fs_info; @@ -181,7 +183,7 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, /* For nocow write, we can release the qgroup rsv right now */ ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes); if (ret < 0) - return ret; + return ERR_PTR(ret); ret = 0; } else { /* @@ -190,11 +192,11 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, */ ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes); if (ret < 0) - return ret; + return ERR_PTR(ret); } entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS); if (!entry) - return -ENOMEM; + return ERR_PTR(-ENOMEM); entry->file_offset = file_offset; entry->num_bytes = num_bytes; @@ -256,6 +258,32 @@ int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, btrfs_mod_outstanding_extents(inode, 1); spin_unlock(&inode->lock); + /* One ref for the returned entry to match semantics of lookup. */ + refcount_inc(&entry->refs); + + return entry; +} + +/* + * Add a new btrfs_ordered_extent for the range, but drop the reference instead + * of returning it to the caller. + */ +int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, + u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, + u64 disk_num_bytes, u64 offset, unsigned flags, + int compress_type) +{ + struct btrfs_ordered_extent *ordered; + + ordered = btrfs_alloc_ordered_extent(inode, file_offset, num_bytes, + ram_bytes, disk_bytenr, + disk_num_bytes, offset, flags, + compress_type); + + if (IS_ERR(ordered)) + return PTR_ERR(ordered); + btrfs_put_ordered_extent(ordered); + return 0; } diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h index eb40cb39f842e6..c00a5a3f060fa2 100644 --- a/fs/btrfs/ordered-data.h +++ b/fs/btrfs/ordered-data.h @@ -178,6 +178,11 @@ void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode, bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode, struct btrfs_ordered_extent **cached, u64 file_offset, u64 io_size); +struct btrfs_ordered_extent *btrfs_alloc_ordered_extent( + struct btrfs_inode *inode, u64 file_offset, + u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, + u64 disk_num_bytes, u64 offset, unsigned long flags, + int compress_type); int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset, u64 num_bytes, u64 ram_bytes, u64 disk_bytenr, u64 disk_num_bytes, u64 offset, unsigned flags,