Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[~shefty/rdma-dev.git] / fs / btrfs / file.c
index ab22ca4f237fcaad91aae7b54bbc675a4d639d30..f447b783bb84ce25af44cb2276b3d49684948166 100644 (file)
@@ -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,