diff options
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index ab22ca4f237f..f447b783bb84 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -24,6 +24,7 @@ #include <linux/string.h> #include <linux/backing-dev.h> #include <linux/mpage.h> +#include <linux/falloc.h> #include <linux/swap.h> #include <linux/writeback.h> #include <linux/statfs.h> @@ -1289,6 +1290,117 @@ static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) return 0; } +static long btrfs_fallocate(struct file *file, int mode, + loff_t offset, loff_t len) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct extent_state *cached_state = NULL; + u64 cur_offset; + u64 last_byte; + u64 alloc_start; + u64 alloc_end; + u64 alloc_hint = 0; + u64 locked_end; + u64 mask = BTRFS_I(inode)->root->sectorsize - 1; + struct extent_map *em; + int ret; + + alloc_start = offset & ~mask; + alloc_end = (offset + len + mask) & ~mask; + + /* We only support the FALLOC_FL_KEEP_SIZE mode */ + if (mode & ~FALLOC_FL_KEEP_SIZE) + return -EOPNOTSUPP; + + /* + * wait for ordered IO before we have any locks. We'll loop again + * below with the locks held. + */ + btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start); + + mutex_lock(&inode->i_mutex); + ret = inode_newsize_ok(inode, alloc_end); + if (ret) + goto out; + + if (alloc_start > inode->i_size) { + ret = btrfs_cont_expand(inode, alloc_start); + if (ret) + goto out; + } + + ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start); + if (ret) + goto out; + + locked_end = alloc_end - 1; + while (1) { + struct btrfs_ordered_extent *ordered; + + /* the extent lock is ordered inside the running + * transaction + */ + lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start, + locked_end, 0, &cached_state, GFP_NOFS); + ordered = btrfs_lookup_first_ordered_extent(inode, + alloc_end - 1); + if (ordered && + ordered->file_offset + ordered->len > alloc_start && + ordered->file_offset < alloc_end) { + btrfs_put_ordered_extent(ordered); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + alloc_start, locked_end, + &cached_state, GFP_NOFS); + /* + * we can't wait on the range with the transaction + * running or with the extent lock held + */ + btrfs_wait_ordered_range(inode, alloc_start, + alloc_end - alloc_start); + } else { + if (ordered) + btrfs_put_ordered_extent(ordered); + break; + } + } + + cur_offset = alloc_start; + while (1) { + em = btrfs_get_extent(inode, NULL, 0, cur_offset, + alloc_end - cur_offset, 0); + BUG_ON(IS_ERR(em) || !em); + last_byte = min(extent_map_end(em), alloc_end); + last_byte = (last_byte + mask) & ~mask; + if (em->block_start == EXTENT_MAP_HOLE || + (cur_offset >= inode->i_size && + !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) { + ret = btrfs_prealloc_file_range(inode, mode, cur_offset, + last_byte - cur_offset, + 1 << inode->i_blkbits, + offset + len, + &alloc_hint); + if (ret < 0) { + free_extent_map(em); + break; + } + } + free_extent_map(em); + + cur_offset = last_byte; + if (cur_offset >= alloc_end) { + ret = 0; + break; + } + } + unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, + &cached_state, GFP_NOFS); + + btrfs_free_reserved_data_space(inode, alloc_end - alloc_start); +out: + mutex_unlock(&inode->i_mutex); + return ret; +} + const struct file_operations btrfs_file_operations = { .llseek = generic_file_llseek, .read = do_sync_read, @@ -1300,6 +1412,7 @@ const struct file_operations btrfs_file_operations = { .open = generic_file_open, .release = btrfs_release_file, .fsync = btrfs_sync_file, + .fallocate = btrfs_fallocate, .unlocked_ioctl = btrfs_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = btrfs_ioctl, |