diff options
| -rw-r--r-- | fs/btrfs/file.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 1be96ba6f6bb..f155179877a6 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -920,26 +920,35 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf, start_pos = pos; vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + + /* do the reserve before the mutex lock in case we have to do some + * flushing. We wouldn't deadlock, but this is more polite. + */ + err = btrfs_reserve_metadata_for_delalloc(root, inode, 1); + if (err) + goto out_nolock; + + mutex_lock(&inode->i_mutex); + current->backing_dev_info = inode->i_mapping->backing_dev_info; err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); if (err) - goto out_nolock; + goto out; + if (count == 0) - goto out_nolock; + goto out; err = file_remove_suid(file); if (err) - goto out_nolock; - - err = btrfs_reserve_metadata_for_delalloc(root, inode, 1); - if (err) - goto out_nolock; + goto out; file_update_time(file); pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); - mutex_lock(&inode->i_mutex); + /* generic_write_checks can change our pos */ + start_pos = pos; + BTRFS_I(inode)->sequence++; first_index = pos >> PAGE_CACHE_SHIFT; last_index = (pos + count) >> PAGE_CACHE_SHIFT; |