| Message ID | 1529060762-4372-3-git-send-email-nborisov@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jun 15, 2018 at 02:05:58PM +0300, Nikolay Borisov wrote: > Those functions are in preparation for adding the freespace tree > repair code since it needs to be able to deal with bitmap based fsts. > This patch adds extent_buffer_bitmap_set and extent_buffer_bitmap_clear > functions. Since in userspace we don't have to deal with page mappings > their implementation is vastly simplified by simply setting each bit in > the passed range. > > Signed-off-by: Nikolay Borisov <nborisov@suse.com> > --- > extent_io.c | 39 +++++++++++++++++++++++++++++++++++++++ > extent_io.h | 15 +++++++++++++++ > 2 files changed, 54 insertions(+) > > diff --git a/extent_io.c b/extent_io.c > index 198492699438..568a12f7084b 100644 > --- a/extent_io.c > +++ b/extent_io.c > @@ -204,6 +204,45 @@ static int clear_state_bit(struct extent_io_tree *tree, > return ret; > } > > +/** > + * extent_buffer_bitmap_set - set an area of a bitmap > + * @eb: the extent buffer > + * @start: offset of the bitmap item in the extent buffer > + * @pos: bit number of the first bit > + * @len: number of bits to set > + */ > +void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, > + unsigned long pos, unsigned long len) > +{ > + u8 *kaddr = (u8 *)eb->data + start; > + > + while (len) { > + le_set_bit(pos, kaddr); > + pos++; > + len--; > + } > +} > + > + > +/** > + * extent_buffer_bitmap_clear - clear an area of a bitmap > + * @eb: the extent buffer > + * @start: offset of the bitmap item in the extent buffer > + * @pos: bit number of the first bit > + * @len: number of bits to clear > + */ > +void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, > + unsigned long pos, unsigned long len) > +{ > + u8 *kaddr = (u8 *)eb->data + start; > + > + while (len) { > + le_clear_bit(pos, kaddr); > + pos++; > + len--; > + } > +} > + Hm, bit-by-bit is pretty slow. We don't have to worry about the kmap nonsense, but we can still do this byte-by-byte: /** * extent_buffer_bitmap_set - set an area of a bitmap * @eb: the extent buffer * @start: offset of the bitmap item in the extent buffer * @pos: bit number of the first bit * @len: number of bits to set */ void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, unsigned long pos, unsigned long len) { u8 *p = (u8 *)eb->data + start + BIT_BYTE(pos); const unsigned int size = pos + len; int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE); u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos); while (len >= bits_to_set) { *p |= mask_to_set; len -= bits_to_set; bits_to_set = BITS_PER_BYTE; mask_to_set = ~0; p++; } if (len) { mask_to_set &= BITMAP_LAST_BYTE_MASK(size); *p |= mask_to_set; } } /** * extent_buffer_bitmap_clear - clear an area of a bitmap * @eb: the extent buffer * @start: offset of the bitmap item in the extent buffer * @pos: bit number of the first bit * @len: number of bits to clear */ void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, unsigned long pos, unsigned long len) { u8 *p = (u8 *)eb->data + start + BIT_BYTE(pos); const unsigned int size = pos + len; int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE); u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos); while (len >= bits_to_clear) { *p &= ~mask_to_clear; len -= bits_to_clear; bits_to_clear = BITS_PER_BYTE; mask_to_clear = ~0; p++; } if (len) { mask_to_clear &= BITMAP_LAST_BYTE_MASK(size); *p &= ~mask_to_clear; } } I'm 95% sure that's right ;) Compare to __bitmap_set() and __bitmap_clear() in the kernel.
diff --git a/extent_io.c b/extent_io.c index 198492699438..568a12f7084b 100644 --- a/extent_io.c +++ b/extent_io.c @@ -204,6 +204,45 @@ static int clear_state_bit(struct extent_io_tree *tree, return ret; } +/** + * extent_buffer_bitmap_set - set an area of a bitmap + * @eb: the extent buffer + * @start: offset of the bitmap item in the extent buffer + * @pos: bit number of the first bit + * @len: number of bits to set + */ +void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, + unsigned long pos, unsigned long len) +{ + u8 *kaddr = (u8 *)eb->data + start; + + while (len) { + le_set_bit(pos, kaddr); + pos++; + len--; + } +} + + +/** + * extent_buffer_bitmap_clear - clear an area of a bitmap + * @eb: the extent buffer + * @start: offset of the bitmap item in the extent buffer + * @pos: bit number of the first bit + * @len: number of bits to clear + */ +void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, + unsigned long pos, unsigned long len) +{ + u8 *kaddr = (u8 *)eb->data + start; + + while (len) { + le_clear_bit(pos, kaddr); + pos++; + len--; + } +} + /* * clear some bits on a range in the tree. */ diff --git a/extent_io.h b/extent_io.h index d407d93d617e..f9097911f5ef 100644 --- a/extent_io.h +++ b/extent_io.h @@ -68,6 +68,17 @@ static inline int le_test_bit(int nr, const u8 *addr) return 1U & (addr[BIT_BYTE(nr)] >> (nr & (BITS_PER_BYTE-1))); } + +static inline void le_set_bit(int nr, u8 *addr) +{ + addr[BIT_BYTE(nr)] |= (1U << (nr & (BITS_PER_BYTE-1))); +} + +static inline void le_clear_bit(int nr, u8 *addr) +{ + addr[BIT_BYTE(nr)] &= ~(1U << (nr & (BITS_PER_BYTE-1))); +} + struct btrfs_fs_info; struct extent_io_tree { @@ -175,4 +186,8 @@ int read_data_from_disk(struct btrfs_fs_info *info, void *buf, u64 offset, u64 bytes, int mirror); int write_data_to_disk(struct btrfs_fs_info *info, void *buf, u64 offset, u64 bytes, int mirror); +void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, + unsigned long pos, unsigned long len); +void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, + unsigned long pos, unsigned long len); #endif
Those functions are in preparation for adding the freespace tree repair code since it needs to be able to deal with bitmap based fsts. This patch adds extent_buffer_bitmap_set and extent_buffer_bitmap_clear functions. Since in userspace we don't have to deal with page mappings their implementation is vastly simplified by simply setting each bit in the passed range. Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- extent_io.c | 39 +++++++++++++++++++++++++++++++++++++++ extent_io.h | 15 +++++++++++++++ 2 files changed, 54 insertions(+)