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btrfs: Factor out write portion of btrfs_get_blocks_direct
Now that the read side is extracted into its own function, do the same to the write side. This leaves btrfs_get_blocks_direct_write with the sole purpose of handling common locking required. Also flip the condition in btrfs_get_blocks_direct_write so that the write case comes first and we check for if (Create) rather than if (!create). This is purely subjective but I believe makes reading a bit more "linear". No functional changes. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov
David Sterba
parent
1c8d0175df
commit
c5794e5178
207
fs/btrfs/inode.c
207
fs/btrfs/inode.c
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@ -7561,6 +7561,104 @@ static int btrfs_get_blocks_direct_read(struct extent_map *em,
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return 0;
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return 0;
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}
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}
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static int btrfs_get_blocks_direct_write(struct extent_map **map,
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struct buffer_head *bh_result,
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struct inode *inode,
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struct btrfs_dio_data *dio_data,
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u64 start, u64 len)
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{
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struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
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struct extent_map *em = *map;
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int ret = 0;
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/*
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* We don't allocate a new extent in the following cases
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*
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* 1) The inode is marked as NODATACOW. In this case we'll just use the
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* existing extent.
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* 2) The extent is marked as PREALLOC. We're good to go here and can
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* just use the extent.
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*
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*/
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if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
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((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
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em->block_start != EXTENT_MAP_HOLE)) {
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int type;
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u64 block_start, orig_start, orig_block_len, ram_bytes;
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if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
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type = BTRFS_ORDERED_PREALLOC;
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else
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type = BTRFS_ORDERED_NOCOW;
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len = min(len, em->len - (start - em->start));
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block_start = em->block_start + (start - em->start);
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if (can_nocow_extent(inode, start, &len, &orig_start,
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&orig_block_len, &ram_bytes) == 1 &&
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btrfs_inc_nocow_writers(fs_info, block_start)) {
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struct extent_map *em2;
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em2 = btrfs_create_dio_extent(inode, start, len,
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orig_start, block_start,
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len, orig_block_len,
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ram_bytes, type);
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btrfs_dec_nocow_writers(fs_info, block_start);
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if (type == BTRFS_ORDERED_PREALLOC) {
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free_extent_map(em);
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*map = em = em2;
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}
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if (em2 && IS_ERR(em2)) {
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ret = PTR_ERR(em2);
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goto out;
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}
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/*
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* For inode marked NODATACOW or extent marked PREALLOC,
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* use the existing or preallocated extent, so does not
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* need to adjust btrfs_space_info's bytes_may_use.
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*/
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btrfs_free_reserved_data_space_noquota(inode, start,
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len);
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goto skip_cow;
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}
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}
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/* this will cow the extent */
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len = bh_result->b_size;
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free_extent_map(em);
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*map = em = btrfs_new_extent_direct(inode, start, len);
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if (IS_ERR(em)) {
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ret = PTR_ERR(em);
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goto out;
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}
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len = min(len, em->len - (start - em->start));
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skip_cow:
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bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
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inode->i_blkbits;
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bh_result->b_size = len;
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bh_result->b_bdev = em->bdev;
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set_buffer_mapped(bh_result);
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if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
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set_buffer_new(bh_result);
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/*
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* Need to update the i_size under the extent lock so buffered
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* readers will get the updated i_size when we unlock.
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*/
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if (!dio_data->overwrite && start + len > i_size_read(inode))
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i_size_write(inode, start + len);
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WARN_ON(dio_data->reserve < len);
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dio_data->reserve -= len;
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dio_data->unsubmitted_oe_range_end = start + len;
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current->journal_info = dio_data;
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out:
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return ret;
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}
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static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
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static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
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struct buffer_head *bh_result, int create)
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struct buffer_head *bh_result, int create)
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{
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{
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@ -7629,7 +7727,16 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
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goto unlock_err;
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goto unlock_err;
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}
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}
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if (!create) {
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if (create) {
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ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
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dio_data, start, len);
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if (ret < 0)
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goto unlock_err;
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/* clear and unlock the entire range */
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clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
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unlock_bits, 1, 0, &cached_state);
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} else {
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ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
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ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
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start, len);
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start, len);
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/* Can be negative only if we read from a hole */
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/* Can be negative only if we read from a hole */
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@ -7650,106 +7757,8 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
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} else {
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} else {
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free_extent_state(cached_state);
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free_extent_state(cached_state);
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}
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}
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free_extent_map(em);
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return 0;
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}
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}
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/*
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* We don't allocate a new extent in the following cases
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*
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* 1) The inode is marked as NODATACOW. In this case we'll just use the
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* existing extent.
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* 2) The extent is marked as PREALLOC. We're good to go here and can
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* just use the extent.
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*
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*/
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if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
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((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
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em->block_start != EXTENT_MAP_HOLE)) {
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int type;
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u64 block_start, orig_start, orig_block_len, ram_bytes;
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if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
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type = BTRFS_ORDERED_PREALLOC;
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else
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type = BTRFS_ORDERED_NOCOW;
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len = min(len, em->len - (start - em->start));
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block_start = em->block_start + (start - em->start);
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if (can_nocow_extent(inode, start, &len, &orig_start,
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&orig_block_len, &ram_bytes) == 1 &&
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btrfs_inc_nocow_writers(fs_info, block_start)) {
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struct extent_map *em2;
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em2 = btrfs_create_dio_extent(inode, start, len,
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orig_start, block_start,
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len, orig_block_len,
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ram_bytes, type);
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btrfs_dec_nocow_writers(fs_info, block_start);
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if (type == BTRFS_ORDERED_PREALLOC) {
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free_extent_map(em);
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em = em2;
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}
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if (em2 && IS_ERR(em2)) {
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ret = PTR_ERR(em2);
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goto unlock_err;
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}
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/*
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* For inode marked NODATACOW or extent marked PREALLOC,
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* use the existing or preallocated extent, so does not
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* need to adjust btrfs_space_info's bytes_may_use.
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*/
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btrfs_free_reserved_data_space_noquota(inode,
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start, len);
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goto unlock;
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}
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}
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/*
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* this will cow the extent, reset the len in case we changed
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* it above
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*/
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len = bh_result->b_size;
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free_extent_map(em);
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em = btrfs_new_extent_direct(inode, start, len);
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if (IS_ERR(em)) {
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ret = PTR_ERR(em);
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goto unlock_err;
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}
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len = min(len, em->len - (start - em->start));
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unlock:
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bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
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inode->i_blkbits;
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bh_result->b_size = len;
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bh_result->b_bdev = em->bdev;
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set_buffer_mapped(bh_result);
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if (create) {
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if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
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set_buffer_new(bh_result);
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/*
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* Need to update the i_size under the extent lock so buffered
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* readers will get the updated i_size when we unlock.
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*/
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if (!dio_data->overwrite && start + len > i_size_read(inode))
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i_size_write(inode, start + len);
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WARN_ON(dio_data->reserve < len);
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dio_data->reserve -= len;
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dio_data->unsubmitted_oe_range_end = start + len;
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current->journal_info = dio_data;
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}
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/*
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* In the case of write we need to clear and unlock the entire range,
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* in the case of read we need to unlock only the end area that we
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* aren't using if there is any left over space.
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*/
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if (lockstart < lockend) {
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clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
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lockend, unlock_bits, 1, 0,
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&cached_state);
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}
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free_extent_map(em);
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free_extent_map(em);
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return 0;
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return 0;
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