diff options
| -rw-r--r-- | fs/btrfs/file.c | 102 | ||||
| -rw-r--r-- | fs/btrfs/inode.c | 8 |
2 files changed, 39 insertions, 71 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index bd329316945f..ceac806155b8 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1460,8 +1460,27 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages, return ret; } -static int check_can_nocow(struct btrfs_inode *inode, loff_t pos, - size_t *write_bytes, bool nowait) +/* + * Check if we can do nocow write into the range [@pos, @pos + @write_bytes) + * + * @pos: File offset. + * @write_bytes: The length to write, will be updated to the nocow writeable + * range. + * + * This function will flush ordered extents in the range to ensure proper + * nocow checks. + * + * Return: + * > 0 If we can nocow, and updates @write_bytes. + * 0 If we can't do a nocow write. + * -EAGAIN If we can't do a nocow write because snapshoting of the inode's + * root is in progress. + * < 0 If an error happened. + * + * NOTE: Callers need to call btrfs_check_nocow_unlock() if we return > 0. + */ +int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos, + size_t *write_bytes) { struct btrfs_fs_info *fs_info = inode->root->fs_info; struct btrfs_root *root = inode->root; @@ -1472,7 +1491,7 @@ static int check_can_nocow(struct btrfs_inode *inode, loff_t pos, if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC))) return 0; - if (!nowait && !btrfs_drew_try_write_lock(&root->snapshot_lock)) + if (!btrfs_drew_try_write_lock(&root->snapshot_lock)) return -EAGAIN; lockstart = round_down(pos, fs_info->sectorsize); @@ -1480,71 +1499,21 @@ static int check_can_nocow(struct btrfs_inode *inode, loff_t pos, fs_info->sectorsize) - 1; num_bytes = lockend - lockstart + 1; - if (nowait) { - struct btrfs_ordered_extent *ordered; - - if (!try_lock_extent(&inode->io_tree, lockstart, lockend)) - return -EAGAIN; - - ordered = btrfs_lookup_ordered_range(inode, lockstart, - num_bytes); - if (ordered) { - btrfs_put_ordered_extent(ordered); - ret = -EAGAIN; - goto out_unlock; - } - } else { - btrfs_lock_and_flush_ordered_range(inode, lockstart, - lockend, NULL); - } - + btrfs_lock_and_flush_ordered_range(inode, lockstart, lockend, NULL); ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes, NULL, NULL, NULL, false); if (ret <= 0) { ret = 0; - if (!nowait) - btrfs_drew_write_unlock(&root->snapshot_lock); + btrfs_drew_write_unlock(&root->snapshot_lock); } else { *write_bytes = min_t(size_t, *write_bytes , num_bytes - pos + lockstart); } -out_unlock: unlock_extent(&inode->io_tree, lockstart, lockend); return ret; } -static int check_nocow_nolock(struct btrfs_inode *inode, loff_t pos, - size_t *write_bytes) -{ - return check_can_nocow(inode, pos, write_bytes, true); -} - -/* - * Check if we can do nocow write into the range [@pos, @pos + @write_bytes) - * - * @pos: File offset - * @write_bytes: The length to write, will be updated to the nocow writeable - * range - * - * This function will flush ordered extents in the range to ensure proper - * nocow checks. - * - * Return: - * >0 and update @write_bytes if we can do nocow write - * 0 if we can't do nocow write - * -EAGAIN if we can't get the needed lock or there are ordered extents - * for * (nowait == true) case - * <0 if other error happened - * - * NOTE: Callers need to release the lock by btrfs_check_nocow_unlock(). - */ -int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos, - size_t *write_bytes) -{ - return check_can_nocow(inode, pos, write_bytes, false); -} - void btrfs_check_nocow_unlock(struct btrfs_inode *inode) { btrfs_drew_write_unlock(&inode->root->snapshot_lock); @@ -1579,20 +1548,15 @@ static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from, loff_t oldsize; loff_t start_pos; - if (iocb->ki_flags & IOCB_NOWAIT) { - size_t nocow_bytes = count; - - /* We will allocate space in case nodatacow is not set, so bail */ - if (check_nocow_nolock(BTRFS_I(inode), pos, &nocow_bytes) <= 0) - return -EAGAIN; - /* - * There are holes in the range or parts of the range that must - * be COWed (shared extents, RO block groups, etc), so just bail - * out. - */ - if (nocow_bytes < count) - return -EAGAIN; - } + /* + * Quickly bail out on NOWAIT writes if we don't have the nodatacow or + * prealloc flags, as without those flags we always have to COW. We will + * later check if we can really COW into the target range (using + * can_nocow_extent() at btrfs_get_blocks_direct_write()). + */ + if ((iocb->ki_flags & IOCB_NOWAIT) && + !(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC))) + return -EAGAIN; current->backing_dev_info = inode_to_bdi(inode); ret = file_remove_privs(file); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index fa5dd209ca58..05cb7b1ab172 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7403,7 +7403,8 @@ static struct extent_map *create_io_em(struct btrfs_inode *inode, u64 start, static int btrfs_get_blocks_direct_write(struct extent_map **map, struct inode *inode, struct btrfs_dio_data *dio_data, - u64 start, u64 len) + u64 start, u64 len, + unsigned int iomap_flags) { struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct extent_map *em = *map; @@ -7473,6 +7474,9 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map, free_extent_map(em); *map = NULL; + if (iomap_flags & IOMAP_NOWAIT) + return -EAGAIN; + /* We have to COW, so need to reserve metadata and data space. */ ret = btrfs_delalloc_reserve_space(BTRFS_I(inode), &dio_data->data_reserved, @@ -7649,7 +7653,7 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start, if (write) { ret = btrfs_get_blocks_direct_write(&em, inode, dio_data, - start, len); + start, len, flags); if (ret < 0) goto unlock_err; unlock_extents = true; |