The original truncation of btrfs has a bug, that is the orphan item will not be
dropped when the truncation fails. This bug will trigger BUG() when unlink that
truncated file. And besides that, if the user does pre-allocation for the file
which is truncated unsuccessfully, after re-mount(umount-mount, not -o remount),
the pre-allocated extent will be dropped.
This patch modified the relative functions of the truncation, and makes the
truncation update i_size and disk_i_size of i-nodes every time we drop the file
extent successfully, and set them to the real value. By this way, we
needn''t
add orphan items to guarantee the consistency of the meta-data.
By this patch, it is possible that the file may not be truncated to the size
that the user expects(may be <= the orignal size and >= the expected one),
so I
think it is better that we shouldn''t lose the data that lies within the
range
<the expected size, the real size>, because the user may take it for
granted
that the data in that extent is not lost. In order to implement it, we just
write out all the dirty pages which are beyond the expected size of the file.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
Changes v1 -> v2:
- None.
---
fs/btrfs/inode.c | 159 +++++++++++++++++-------------------------------------
1 files changed, 49 insertions(+), 110 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4d1d4c4..77a295d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -88,7 +88,7 @@ static unsigned char btrfs_type_by_mode[S_IFMT >>
S_SHIFT] = {
};
static int btrfs_setsize(struct inode *inode, loff_t newsize);
-static int btrfs_truncate(struct inode *inode);
+static int btrfs_truncate(struct inode *inode, loff_t newsize);
static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
static noinline int cow_file_range(struct inode *inode,
struct page *locked_page,
@@ -2230,7 +2230,7 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
* btrfs_delalloc_reserve_space to catch offenders.
*/
mutex_lock(&inode->i_mutex);
- ret = btrfs_truncate(inode);
+ ret = btrfs_truncate(inode, inode->i_size);
mutex_unlock(&inode->i_mutex);
} else {
nr_unlink++;
@@ -2993,7 +2993,7 @@ static int btrfs_release_and_test_inline_data_extent(
return 0;
/*
- * Truncate inline items is special, we have done it by
+ * Truncate inline items is special, we will do it by
* btrfs_truncate_page();
*/
if (offset < new_size)
@@ -3124,9 +3124,9 @@ static int btrfs_release_and_test_data_extent(struct
btrfs_trans_handle *trans,
* will kill all the items on this inode, including the INODE_ITEM_KEY.
*/
int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct inode *inode,
- u64 new_size, u32 min_type)
+ struct btrfs_root *root,
+ struct inode *inode,
+ u64 new_size, u32 min_type)
{
struct btrfs_path *path;
struct extent_buffer *leaf;
@@ -3134,6 +3134,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle
*trans,
struct btrfs_key found_key;
u64 mask = root->sectorsize - 1;
u64 ino = btrfs_ino(inode);
+ u64 old_size = i_size_read(inode);
u32 found_type;
int pending_del_nr = 0;
int pending_del_slot = 0;
@@ -3141,6 +3142,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle
*trans,
int err = 0;
BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
+ BUG_ON(new_size & mask);
path = btrfs_alloc_path();
if (!path)
@@ -3193,6 +3195,13 @@ search_again:
ret = btrfs_release_and_test_data_extent(trans, root,
path, inode, found_key.offset,
new_size);
+ if (root->ref_cows ||
+ root == root->fs_info->tree_root) {
+ if (ret && found_key.offset < old_size)
+ i_size_write(inode, found_key.offset);
+ else if (!ret)
+ i_size_write(inode, new_size);
+ }
if (!ret)
break;
}
@@ -3250,12 +3259,10 @@ out:
static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
{
struct inode *inode = mapping->host;
- struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
struct btrfs_ordered_extent *ordered;
struct extent_state *cached_state = NULL;
char *kaddr;
- u32 blocksize = root->sectorsize;
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
struct page *page;
@@ -3264,8 +3271,6 @@ static int btrfs_truncate_page(struct address_space
*mapping, loff_t from)
u64 page_start;
u64 page_end;
- if ((offset & (blocksize - 1)) == 0)
- goto out;
ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
if (ret)
goto out;
@@ -3332,6 +3337,7 @@ again:
}
ClearPageChecked(page);
set_page_dirty(page);
+ i_size_write(inode, from);
unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
GFP_NOFS);
@@ -3462,7 +3468,9 @@ static int btrfs_setsize(struct inode *inode, loff_t
newsize)
ret = btrfs_update_inode(trans, root, inode);
btrfs_end_transaction_throttle(trans, root);
} else {
-
+ btrfs_wait_ordered_range(inode,
+ newsize & ~(root->sectorsize - 1),
+ (u64)-1);
/*
* We''re truncating a file that used to have good data down to
* zero. Make sure it gets into the ordered flush list so that
@@ -3472,8 +3480,8 @@ static int btrfs_setsize(struct inode *inode, loff_t
newsize)
BTRFS_I(inode)->ordered_data_close = 1;
/* we don''t support swapfiles, so vmtruncate shouldn''t fail
*/
- truncate_setsize(inode, newsize);
- ret = btrfs_truncate(inode);
+ truncate_pagecache(inode, oldsize, newsize);
+ ret = btrfs_truncate(inode, newsize);
}
return ret;
@@ -6525,87 +6533,43 @@ out:
return ret;
}
-static int btrfs_truncate(struct inode *inode)
+static int btrfs_truncate(struct inode *inode, loff_t newsize)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
- struct btrfs_block_rsv *rsv;
int ret;
int err = 0;
struct btrfs_trans_handle *trans;
unsigned long nr;
u64 mask = root->sectorsize - 1;
- u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
-
- ret = btrfs_truncate_page(inode->i_mapping, inode->i_size);
- if (ret)
- return ret;
-
- btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
- btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
/*
* Yes ladies and gentelment, this is indeed ugly. The fact is we have
- * 3 things going on here
+ * 2 things going on here
*
- * 1) We need to reserve space for our orphan item and the space to
- * delete our orphan item. Lord knows we don''t want to have a
dangling
- * orphan item because we didn''t reserve space to remove it.
+ * 1) We need to reserve space to update our inode.
*
- * 2) We need to reserve space to update our inode.
- *
- * 3) We need to have something to cache all the space that is going to
+ * 2) We need to have something to cache all the space that is going to
* be free''d up by the truncate operation, but also have some slack
* space reserved in case it uses space during the truncate (thank you
* very much snapshotting).
*
- * And we need these to all be seperate. The fact is we can use alot of
- * space doing the truncate, and we have no earthly idea how much space
- * we will use, so we need the truncate reservation to be seperate so it
- * doesn''t end up using space reserved for updating the inode or
- * removing the orphan item. We also need to be able to stop the
- * transaction and start a new one, which means we need to be able to
- * update the inode several times, and we have no idea of knowing how
- * many times that will be, so we can''t just reserve 1 item for the
- * entirety of the opration, so that has to be done seperately as well.
- * Then there is the orphan item, which does indeed need to be held on
- * to for the whole operation, and we need nobody to touch this reserved
- * space except the orphan code.
- *
- * So that leaves us with
- *
- * 1) root->orphan_block_rsv - for the orphan deletion.
- * 2) rsv - for the truncate reservation, which we will steal from the
- * transaction reservation.
- * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
- * updating the inode.
+ * And we need these to all be seperate. The fact is we can use a lot
+ * of space doing the truncate, and we have no earthly idea how much
+ * space we will use, so we need the truncate reservation to be
+ * seperate. We also need to be able to stop the transaction and start
+ * a new one, which means we need to be able to update the inode several
+ * times, and we have no idea of knowing how many times that will be,
+ * so we can''t just reserve 1 item for the entirety of the operation,
+ * so that has to be done seperately as well.
*/
- rsv = btrfs_alloc_block_rsv(root);
- if (!rsv)
- return -ENOMEM;
- rsv->size = min_size;
/*
* 1 for the truncate slack space
- * 1 for the orphan item we''re going to add
- * 1 for the orphan item deletion
* 1 for updating the inode.
*/
- trans = btrfs_start_transaction(root, 4);
- if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
- goto out;
- }
-
- /* Migrate the slack space for the truncate to our reserve */
- ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
- min_size);
- BUG_ON(ret);
-
- ret = btrfs_orphan_add(trans, inode);
- if (ret) {
- btrfs_end_transaction(trans, root);
- goto out;
- }
+ trans = btrfs_start_transaction(root, 2);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
/*
* setattr is responsible for setting the ordered_data_close flag,
@@ -6624,26 +6588,12 @@ static int btrfs_truncate(struct inode *inode)
* using truncate to replace the contents of the file will
* end up with a zero length file after a crash.
*/
- if (inode->i_size == 0 && BTRFS_I(inode)->ordered_data_close)
+ if (newsize == 0 && BTRFS_I(inode)->ordered_data_close)
btrfs_add_ordered_operation(trans, root, inode);
while (1) {
- ret = btrfs_block_rsv_refill(root, rsv, min_size);
- if (ret) {
- /*
- * This can only happen with the original transaction we
- * started above, every other time we shouldn''t have a
- * transaction started yet.
- */
- if (ret == -EAGAIN)
- goto end_trans;
- err = ret;
- break;
- }
-
if (!trans) {
- /* Just need the 1 for updating the inode */
- trans = btrfs_start_transaction(root, 1);
+ trans = btrfs_start_transaction(root, 2);
if (IS_ERR(trans)) {
ret = err = PTR_ERR(trans);
trans = NULL;
@@ -6651,44 +6601,28 @@ static int btrfs_truncate(struct inode *inode)
}
}
- trans->block_rsv = rsv;
-
ret = btrfs_truncate_inode_items(trans, root, inode,
- inode->i_size,
+ round_up(newsize, mask + 1),
BTRFS_EXTENT_DATA_KEY);
+ btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
if (ret != -EAGAIN) {
err = ret;
break;
}
- trans->block_rsv = &root->fs_info->trans_block_rsv;
ret = btrfs_update_inode(trans, root, inode);
if (ret) {
err = ret;
break;
}
-end_trans:
+
nr = trans->blocks_used;
btrfs_end_transaction(trans, root);
trans = NULL;
btrfs_btree_balance_dirty(root, nr);
}
- if (ret == 0 && inode->i_nlink > 0) {
- trans->block_rsv = root->orphan_block_rsv;
- ret = btrfs_orphan_del(trans, inode);
- if (ret)
- err = ret;
- } else if (ret && inode->i_nlink > 0) {
- /*
- * Failed to do the truncate, remove us from the in memory
- * orphan list.
- */
- ret = btrfs_orphan_del(NULL, inode);
- }
-
if (trans) {
- trans->block_rsv = &root->fs_info->trans_block_rsv;
ret = btrfs_update_inode(trans, root, inode);
if (ret && !err)
err = ret;
@@ -6698,12 +6632,17 @@ end_trans:
btrfs_btree_balance_dirty(root, nr);
}
-out:
- btrfs_free_block_rsv(root, rsv);
-
if (ret && !err)
err = ret;
+ if (!err && (newsize & mask)) {
+ ret = btrfs_truncate_page(inode->i_mapping, newsize);
+ if (ret)
+ return ret;
+
+ btrfs_wait_ordered_range(inode, newsize & (~mask), (u64)-1);
+ }
+
return err;
}
--
1.7.6.5
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