| Message ID | 20160706103753.4908-2-wangxg.fnst@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 07/06/16 12:37, Wang Xiaoguang wrote: > Below test scripts can reproduce this false ENOSPC: > #!/bin/bash > dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 > dev=$(losetup --show -f fs.img) > mkfs.btrfs -f -M $dev > mkdir /tmp/mntpoint > mount /dev/loop0 /tmp/mntpoint > cd mntpoint > xfs_io -f -c "falloc 0 $((40*1024*1024))" testfile > > Above fallocate(2) operation will fail for ENOSPC reason, but indeed > fs still has free space to satisfy this request. The reason is > btrfs_fallocate() dose not decrease btrfs_space_info's bytes_may_use > just in time, and it calls btrfs_free_reserved_data_space_noquota() in > the end of btrfs_fallocate(), which is too late and have already added > false unnecessary pressure to enospc system. See call graph: > btrfs_fallocate() > |-> btrfs_alloc_data_chunk_ondemand() > It will add btrfs_space_info's bytes_may_use accordingly. > |-> btrfs_prealloc_file_range() > It will call btrfs_reserve_extent(), but note that alloc type is > RESERVE_ALLOC_NO_ACCOUNT, so btrfs_update_reserved_bytes() will > only increase btrfs_space_info's bytes_reserved accordingly, but > will not decrease btrfs_space_info's bytes_may_use, then obviously > we have overestimated real needed disk space, and it'll impact > other processes who do write(2) or fallocate(2) operations, also > can impact metadata reservation in mixed mode, and bytes_max_use > will only be decreased in the end of btrfs_fallocate(). To fix > this false ENOSPC, we need to decrease btrfs_space_info's > bytes_may_use in btrfs_prealloc_file_range() in time, as what we > do in cow_file_range(), > See call graph in : > cow_file_range() > |-> extent_clear_unlock_delalloc() > |-> clear_extent_bit() > |-> btrfs_clear_bit_hook() > |-> btrfs_free_reserved_data_space_noquota() > This function will decrease bytes_may_use accordingly. > > So this patch choose to call btrfs_free_reserved_data_space() in > __btrfs_prealloc_file_range() for both successful and failed path. > > Also this patch removes some old and useless comments. > > Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Verified that the reproducer script indeed fails (with btrfs ~4.7) and the patch (on top of 1/2) fixes it. Also ran a bunch of other fallocating things without problem. Free space also still seems sane, as far as I could tell. So for both patches: Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> cheers, Holger -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
hello, On 07/06/2016 08:27 PM, Holger Hoffstätte wrote: > On 07/06/16 12:37, Wang Xiaoguang wrote: >> Below test scripts can reproduce this false ENOSPC: >> #!/bin/bash >> dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 >> dev=$(losetup --show -f fs.img) >> mkfs.btrfs -f -M $dev >> mkdir /tmp/mntpoint >> mount /dev/loop0 /tmp/mntpoint >> cd mntpoint >> xfs_io -f -c "falloc 0 $((40*1024*1024))" testfile >> >> Above fallocate(2) operation will fail for ENOSPC reason, but indeed >> fs still has free space to satisfy this request. The reason is >> btrfs_fallocate() dose not decrease btrfs_space_info's bytes_may_use >> just in time, and it calls btrfs_free_reserved_data_space_noquota() in >> the end of btrfs_fallocate(), which is too late and have already added >> false unnecessary pressure to enospc system. See call graph: >> btrfs_fallocate() >> |-> btrfs_alloc_data_chunk_ondemand() >> It will add btrfs_space_info's bytes_may_use accordingly. >> |-> btrfs_prealloc_file_range() >> It will call btrfs_reserve_extent(), but note that alloc type is >> RESERVE_ALLOC_NO_ACCOUNT, so btrfs_update_reserved_bytes() will >> only increase btrfs_space_info's bytes_reserved accordingly, but >> will not decrease btrfs_space_info's bytes_may_use, then obviously >> we have overestimated real needed disk space, and it'll impact >> other processes who do write(2) or fallocate(2) operations, also >> can impact metadata reservation in mixed mode, and bytes_max_use >> will only be decreased in the end of btrfs_fallocate(). To fix >> this false ENOSPC, we need to decrease btrfs_space_info's >> bytes_may_use in btrfs_prealloc_file_range() in time, as what we >> do in cow_file_range(), >> See call graph in : >> cow_file_range() >> |-> extent_clear_unlock_delalloc() >> |-> clear_extent_bit() >> |-> btrfs_clear_bit_hook() >> |-> btrfs_free_reserved_data_space_noquota() >> This function will decrease bytes_may_use accordingly. >> >> So this patch choose to call btrfs_free_reserved_data_space() in >> __btrfs_prealloc_file_range() for both successful and failed path. >> >> Also this patch removes some old and useless comments. >> >> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> > Verified that the reproducer script indeed fails (with btrfs ~4.7) and > the patch (on top of 1/2) fixes it. Also ran a bunch of other fallocating > things without problem. Free space also still seems sane, as far as I > could tell. > > So for both patches: > > Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Thanks very much :) Regards, Xiaoguang Wang > > cheers, > Holger > > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
hello, Please ignore this patch, though this patch is correct to me, and pass the fstests test. I have prepared a new common patch to fix this false ENOSPC bug. Currently I'm doing fstests test, and will sent them tomorrow, thanks. Regards, Xiaoguang Wang On 07/06/2016 06:37 PM, Wang Xiaoguang wrote: > Below test scripts can reproduce this false ENOSPC: > #!/bin/bash > dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 > dev=$(losetup --show -f fs.img) > mkfs.btrfs -f -M $dev > mkdir /tmp/mntpoint > mount /dev/loop0 /tmp/mntpoint > cd mntpoint > xfs_io -f -c "falloc 0 $((40*1024*1024))" testfile > > Above fallocate(2) operation will fail for ENOSPC reason, but indeed > fs still has free space to satisfy this request. The reason is > btrfs_fallocate() dose not decrease btrfs_space_info's bytes_may_use > just in time, and it calls btrfs_free_reserved_data_space_noquota() in > the end of btrfs_fallocate(), which is too late and have already added > false unnecessary pressure to enospc system. See call graph: > btrfs_fallocate() > |-> btrfs_alloc_data_chunk_ondemand() > It will add btrfs_space_info's bytes_may_use accordingly. > |-> btrfs_prealloc_file_range() > It will call btrfs_reserve_extent(), but note that alloc type is > RESERVE_ALLOC_NO_ACCOUNT, so btrfs_update_reserved_bytes() will > only increase btrfs_space_info's bytes_reserved accordingly, but > will not decrease btrfs_space_info's bytes_may_use, then obviously > we have overestimated real needed disk space, and it'll impact > other processes who do write(2) or fallocate(2) operations, also > can impact metadata reservation in mixed mode, and bytes_max_use > will only be decreased in the end of btrfs_fallocate(). To fix > this false ENOSPC, we need to decrease btrfs_space_info's > bytes_may_use in btrfs_prealloc_file_range() in time, as what we > do in cow_file_range(), > See call graph in : > cow_file_range() > |-> extent_clear_unlock_delalloc() > |-> clear_extent_bit() > |-> btrfs_clear_bit_hook() > |-> btrfs_free_reserved_data_space_noquota() > This function will decrease bytes_may_use accordingly. > > So this patch choose to call btrfs_free_reserved_data_space() in > __btrfs_prealloc_file_range() for both successful and failed path. > > Also this patch removes some old and useless comments. > > Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> > --- > fs/btrfs/extent-tree.c | 1 - > fs/btrfs/file.c | 23 ++++++++++++----------- > fs/btrfs/inode-map.c | 3 +-- > fs/btrfs/inode.c | 12 ++++++++++++ > fs/btrfs/relocation.c | 10 +++++++++- > 5 files changed, 34 insertions(+), 15 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 82b912a..b0c86d2 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -3490,7 +3490,6 @@ again: > dcs = BTRFS_DC_SETUP; > else if (ret == -ENOSPC) > set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags); > - btrfs_free_reserved_data_space(inode, 0, num_pages); > > out_put: > iput(inode); > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 2234e88..f872113 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -2669,6 +2669,7 @@ static long btrfs_fallocate(struct file *file, int mode, > > alloc_start = round_down(offset, blocksize); > alloc_end = round_up(offset + len, blocksize); > + cur_offset = alloc_start; > > /* Make sure we aren't being give some crap mode */ > if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) > @@ -2761,7 +2762,6 @@ static long btrfs_fallocate(struct file *file, int mode, > > /* First, check if we exceed the qgroup limit */ > INIT_LIST_HEAD(&reserve_list); > - cur_offset = alloc_start; > while (1) { > em = btrfs_get_extent(inode, NULL, 0, cur_offset, > alloc_end - cur_offset, 0); > @@ -2788,6 +2788,14 @@ static long btrfs_fallocate(struct file *file, int mode, > last_byte - cur_offset); > if (ret < 0) > break; > + } else { > + /* > + * Do not need to reserve unwritten extent for this > + * range, free reserved data space first, otherwise > + * it'll result false ENOSPC error. > + */ > + btrfs_free_reserved_data_space(inode, cur_offset, > + last_byte - cur_offset); > } > free_extent_map(em); > cur_offset = last_byte; > @@ -2839,18 +2847,11 @@ out_unlock: > unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, > &cached_state, GFP_KERNEL); > out: > - /* > - * As we waited the extent range, the data_rsv_map must be empty > - * in the range, as written data range will be released from it. > - * And for prealloacted extent, it will also be released when > - * its metadata is written. > - * So this is completely used as cleanup. > - */ > - btrfs_qgroup_free_data(inode, alloc_start, alloc_end - alloc_start); > inode_unlock(inode); > /* Let go of our reservation. */ > - btrfs_free_reserved_data_space(inode, alloc_start, > - alloc_end - alloc_start); > + if (ret != 0) > + btrfs_free_reserved_data_space(inode, cur_offset, > + alloc_end - cur_offset); > return ret; > } > > diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c > index 70107f7..e59e7d6 100644 > --- a/fs/btrfs/inode-map.c > +++ b/fs/btrfs/inode-map.c > @@ -495,10 +495,9 @@ again: > ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc, > prealloc, prealloc, &alloc_hint); > if (ret) { > - btrfs_delalloc_release_space(inode, 0, prealloc); > + btrfs_delalloc_release_metadata(inode, prealloc); > goto out_put; > } > - btrfs_free_reserved_data_space(inode, 0, prealloc); > > ret = btrfs_write_out_ino_cache(root, trans, path, inode); > out_put: > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 4421954..4dc7c838 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -10269,6 +10269,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode, > u64 last_alloc = (u64)-1; > int ret = 0; > bool own_trans = true; > + u64 end = start + num_bytes - 1; > > if (trans) > own_trans = false; > @@ -10347,6 +10348,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode, > } > free_extent_map(em); > next: > + btrfs_free_reserved_data_space(inode, cur_offset, ins.offset); > num_bytes -= ins.offset; > cur_offset += ins.offset; > *alloc_hint = ins.objectid + ins.offset; > @@ -10377,9 +10379,18 @@ next: > if (own_trans) > btrfs_end_transaction(trans, root); > } > + > + if (cur_offset < end) > + btrfs_free_reserved_data_space(inode, cur_offset, > + end - cur_offset + 1); > return ret; > } > > +/* > + * __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() > + * internally for both sucessful and failed path, btrfs_prealloc_file_range()'s > + * callers does not need to call btrfs_free_reserved_data_space() any more. > + */ > int btrfs_prealloc_file_range(struct inode *inode, int mode, > u64 start, u64 num_bytes, u64 min_size, > loff_t actual_len, u64 *alloc_hint) > @@ -10389,6 +10400,7 @@ int btrfs_prealloc_file_range(struct inode *inode, int mode, > NULL); > } > > +/* Please see same comments in btrfs_prealloc_file_range() */ > int btrfs_prealloc_file_range_trans(struct inode *inode, > struct btrfs_trans_handle *trans, int mode, > u64 start, u64 num_bytes, u64 min_size, > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index abc2f69..70756fd 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -3031,6 +3031,7 @@ int prealloc_file_extent_cluster(struct inode *inode, > int nr = 0; > int ret = 0; > u64 prealloc_start, prealloc_end; > + u64 cur_offset; > > BUG_ON(cluster->start != cluster->boundary[0]); > inode_lock(inode); > @@ -3041,6 +3042,7 @@ int prealloc_file_extent_cluster(struct inode *inode, > if (ret) > goto out; > > + cur_offset = start; > while (nr < cluster->nr) { > prealloc_start = cluster->boundary[nr] - offset; > if (nr + 1 < cluster->nr) > @@ -3051,16 +3053,22 @@ int prealloc_file_extent_cluster(struct inode *inode, > lock_extent(&BTRFS_I(inode)->io_tree, prealloc_start, > prealloc_end); > num_bytes = prealloc_end + 1 - prealloc_start; > + if (cur_offset < start) > + btrfs_free_reserved_data_space(inode, cur_offset, > + start - cur_offset); > ret = btrfs_prealloc_file_range(inode, 0, prealloc_start, > num_bytes, num_bytes, > prealloc_end + 1, &alloc_hint); > unlock_extent(&BTRFS_I(inode)->io_tree, prealloc_start, > prealloc_end); > + cur_offset = prealloc_end + 1; > if (ret) > break; > nr++; > } > - btrfs_free_reserved_data_space(inode, start, end + 1 - start); > + if (cur_offset < end) > + btrfs_free_reserved_data_space(inode, cur_offset, > + end + 1 - cur_offset); > out: > inode_unlock(inode); > return ret; -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 82b912a..b0c86d2 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3490,7 +3490,6 @@ again: dcs = BTRFS_DC_SETUP; else if (ret == -ENOSPC) set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags); - btrfs_free_reserved_data_space(inode, 0, num_pages); out_put: iput(inode); diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 2234e88..f872113 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2669,6 +2669,7 @@ static long btrfs_fallocate(struct file *file, int mode, alloc_start = round_down(offset, blocksize); alloc_end = round_up(offset + len, blocksize); + cur_offset = alloc_start; /* Make sure we aren't being give some crap mode */ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) @@ -2761,7 +2762,6 @@ static long btrfs_fallocate(struct file *file, int mode, /* First, check if we exceed the qgroup limit */ INIT_LIST_HEAD(&reserve_list); - cur_offset = alloc_start; while (1) { em = btrfs_get_extent(inode, NULL, 0, cur_offset, alloc_end - cur_offset, 0); @@ -2788,6 +2788,14 @@ static long btrfs_fallocate(struct file *file, int mode, last_byte - cur_offset); if (ret < 0) break; + } else { + /* + * Do not need to reserve unwritten extent for this + * range, free reserved data space first, otherwise + * it'll result false ENOSPC error. + */ + btrfs_free_reserved_data_space(inode, cur_offset, + last_byte - cur_offset); } free_extent_map(em); cur_offset = last_byte; @@ -2839,18 +2847,11 @@ out_unlock: unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, &cached_state, GFP_KERNEL); out: - /* - * As we waited the extent range, the data_rsv_map must be empty - * in the range, as written data range will be released from it. - * And for prealloacted extent, it will also be released when - * its metadata is written. - * So this is completely used as cleanup. - */ - btrfs_qgroup_free_data(inode, alloc_start, alloc_end - alloc_start); inode_unlock(inode); /* Let go of our reservation. */ - btrfs_free_reserved_data_space(inode, alloc_start, - alloc_end - alloc_start); + if (ret != 0) + btrfs_free_reserved_data_space(inode, cur_offset, + alloc_end - cur_offset); return ret; } diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c index 70107f7..e59e7d6 100644 --- a/fs/btrfs/inode-map.c +++ b/fs/btrfs/inode-map.c @@ -495,10 +495,9 @@ again: ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc, prealloc, prealloc, &alloc_hint); if (ret) { - btrfs_delalloc_release_space(inode, 0, prealloc); + btrfs_delalloc_release_metadata(inode, prealloc); goto out_put; } - btrfs_free_reserved_data_space(inode, 0, prealloc); ret = btrfs_write_out_ino_cache(root, trans, path, inode); out_put: diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 4421954..4dc7c838 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -10269,6 +10269,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode, u64 last_alloc = (u64)-1; int ret = 0; bool own_trans = true; + u64 end = start + num_bytes - 1; if (trans) own_trans = false; @@ -10347,6 +10348,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode, } free_extent_map(em); next: + btrfs_free_reserved_data_space(inode, cur_offset, ins.offset); num_bytes -= ins.offset; cur_offset += ins.offset; *alloc_hint = ins.objectid + ins.offset; @@ -10377,9 +10379,18 @@ next: if (own_trans) btrfs_end_transaction(trans, root); } + + if (cur_offset < end) + btrfs_free_reserved_data_space(inode, cur_offset, + end - cur_offset + 1); return ret; } +/* + * __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() + * internally for both sucessful and failed path, btrfs_prealloc_file_range()'s + * callers does not need to call btrfs_free_reserved_data_space() any more. + */ int btrfs_prealloc_file_range(struct inode *inode, int mode, u64 start, u64 num_bytes, u64 min_size, loff_t actual_len, u64 *alloc_hint) @@ -10389,6 +10400,7 @@ int btrfs_prealloc_file_range(struct inode *inode, int mode, NULL); } +/* Please see same comments in btrfs_prealloc_file_range() */ int btrfs_prealloc_file_range_trans(struct inode *inode, struct btrfs_trans_handle *trans, int mode, u64 start, u64 num_bytes, u64 min_size, diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index abc2f69..70756fd 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3031,6 +3031,7 @@ int prealloc_file_extent_cluster(struct inode *inode, int nr = 0; int ret = 0; u64 prealloc_start, prealloc_end; + u64 cur_offset; BUG_ON(cluster->start != cluster->boundary[0]); inode_lock(inode); @@ -3041,6 +3042,7 @@ int prealloc_file_extent_cluster(struct inode *inode, if (ret) goto out; + cur_offset = start; while (nr < cluster->nr) { prealloc_start = cluster->boundary[nr] - offset; if (nr + 1 < cluster->nr) @@ -3051,16 +3053,22 @@ int prealloc_file_extent_cluster(struct inode *inode, lock_extent(&BTRFS_I(inode)->io_tree, prealloc_start, prealloc_end); num_bytes = prealloc_end + 1 - prealloc_start; + if (cur_offset < start) + btrfs_free_reserved_data_space(inode, cur_offset, + start - cur_offset); ret = btrfs_prealloc_file_range(inode, 0, prealloc_start, num_bytes, num_bytes, prealloc_end + 1, &alloc_hint); unlock_extent(&BTRFS_I(inode)->io_tree, prealloc_start, prealloc_end); + cur_offset = prealloc_end + 1; if (ret) break; nr++; } - btrfs_free_reserved_data_space(inode, start, end + 1 - start); + if (cur_offset < end) + btrfs_free_reserved_data_space(inode, cur_offset, + end + 1 - cur_offset); out: inode_unlock(inode); return ret;
Below test scripts can reproduce this false ENOSPC: #!/bin/bash dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 dev=$(losetup --show -f fs.img) mkfs.btrfs -f -M $dev mkdir /tmp/mntpoint mount /dev/loop0 /tmp/mntpoint cd mntpoint xfs_io -f -c "falloc 0 $((40*1024*1024))" testfile Above fallocate(2) operation will fail for ENOSPC reason, but indeed fs still has free space to satisfy this request. The reason is btrfs_fallocate() dose not decrease btrfs_space_info's bytes_may_use just in time, and it calls btrfs_free_reserved_data_space_noquota() in the end of btrfs_fallocate(), which is too late and have already added false unnecessary pressure to enospc system. See call graph: btrfs_fallocate() |-> btrfs_alloc_data_chunk_ondemand() It will add btrfs_space_info's bytes_may_use accordingly. |-> btrfs_prealloc_file_range() It will call btrfs_reserve_extent(), but note that alloc type is RESERVE_ALLOC_NO_ACCOUNT, so btrfs_update_reserved_bytes() will only increase btrfs_space_info's bytes_reserved accordingly, but will not decrease btrfs_space_info's bytes_may_use, then obviously we have overestimated real needed disk space, and it'll impact other processes who do write(2) or fallocate(2) operations, also can impact metadata reservation in mixed mode, and bytes_max_use will only be decreased in the end of btrfs_fallocate(). To fix this false ENOSPC, we need to decrease btrfs_space_info's bytes_may_use in btrfs_prealloc_file_range() in time, as what we do in cow_file_range(), See call graph in : cow_file_range() |-> extent_clear_unlock_delalloc() |-> clear_extent_bit() |-> btrfs_clear_bit_hook() |-> btrfs_free_reserved_data_space_noquota() This function will decrease bytes_may_use accordingly. So this patch choose to call btrfs_free_reserved_data_space() in __btrfs_prealloc_file_range() for both successful and failed path. Also this patch removes some old and useless comments. Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> --- fs/btrfs/extent-tree.c | 1 - fs/btrfs/file.c | 23 ++++++++++++----------- fs/btrfs/inode-map.c | 3 +-- fs/btrfs/inode.c | 12 ++++++++++++ fs/btrfs/relocation.c | 10 +++++++++- 5 files changed, 34 insertions(+), 15 deletions(-)