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ext4: refactor truncate code 

Move common code in ext4_ind_truncate() and ext4_ext_truncate() into
ext4_truncate().  This saves over 60 lines of code.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2013-04-03 12:47:17 -04:00
parent 26a4c0c6cc
commit 819c4920b7
4 changed files with 78 additions and 148 deletions
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4
fs/ext4/ext4.h
View File

@ -2109,7 +2109,7 @@ extern ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
unsigned long nr_segs);
extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk);
extern void ext4_ind_truncate(struct inode *inode);
extern void ext4_ind_truncate(handle_t *, struct inode *inode);
extern int ext4_free_hole_blocks(handle_t *handle, struct inode *inode,
ext4_lblk_t first, ext4_lblk_t stop);
@ -2575,7 +2575,7 @@ extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
int chunk);
extern int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
struct ext4_map_blocks *map, int flags);
extern void ext4_ext_truncate(struct inode *);
extern void ext4_ext_truncate(handle_t *, struct inode *);
extern int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
ext4_lblk_t end);
extern void ext4_ext_init(struct super_block *);

60
fs/ext4/extents.c
View File

@ -4257,47 +4257,12 @@ out3:
return err ? err : allocated;
}
void ext4_ext_truncate(struct inode *inode)
void ext4_ext_truncate(handle_t *handle, struct inode *inode)
{
struct address_space *mapping = inode->i_mapping;
struct super_block *sb = inode->i_sb;
ext4_lblk_t last_block;
handle_t *handle;
loff_t page_len;
int err = 0;
/*
* finish any pending end_io work so we won't run the risk of
* converting any truncated blocks to initialized later
*/
ext4_flush_unwritten_io(inode);
/*
* probably first extent we're gonna free will be last in block
*/
err = ext4_writepage_trans_blocks(inode);
handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, err);
if (IS_ERR(handle))
return;
if (inode->i_size % PAGE_CACHE_SIZE != 0) {
page_len = PAGE_CACHE_SIZE -
(inode->i_size & (PAGE_CACHE_SIZE - 1));
err = ext4_discard_partial_page_buffers(handle,
mapping, inode->i_size, page_len, 0);
if (err)
goto out_stop;
}
if (ext4_orphan_add(handle, inode))
goto out_stop;
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode);
/*
* TODO: optimization is possible here.
* Probably we need not scan at all,
@ -4313,29 +4278,6 @@ void ext4_ext_truncate(struct inode *inode)
err = ext4_es_remove_extent(inode, last_block,
EXT_MAX_BLOCKS - last_block);
err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
/* In a multi-transaction truncate, we only make the final
* transaction synchronous.
*/
if (IS_SYNC(inode))
ext4_handle_sync(handle);
up_write(&EXT4_I(inode)->i_data_sem);
out_stop:
/*
* If this was a simple ftruncate() and the file will remain alive,
* then we need to clear up the orphan record which we created above.
* However, if this was a real unlink then we were called by
* ext4_delete_inode(), and we allow that function to clean up the
* orphan info for us.
*/
if (inode->i_nlink)
ext4_orphan_del(handle, inode);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
ext4_journal_stop(handle);
}
static void ext4_falloc_update_inode(struct inode *inode,

88
fs/ext4/indirect.c
View File

@ -806,26 +806,9 @@ int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk)
* be able to restart the transaction at a conventient checkpoint to make
* sure we don't overflow the journal.
*
* start_transaction gets us a new handle for a truncate transaction,
* and extend_transaction tries to extend the existing one a bit. If
* Try to extend this transaction for the purposes of truncation. If
* extend fails, we need to propagate the failure up and restart the
* transaction in the top-level truncate loop. --sct
*/
static handle_t *start_transaction(struct inode *inode)
{
handle_t *result;
result = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
ext4_blocks_for_truncate(inode));
if (!IS_ERR(result))
return result;
ext4_std_error(inode->i_sb, PTR_ERR(result));
return result;
}
/*
* Try to extend this transaction for the purposes of truncation.
*
* Returns 0 if we managed to create more room. If we can't create more
* room, and the transaction must be restarted we return 1.
@ -1218,68 +1201,30 @@ static void ext4_free_branches(handle_t *handle, struct inode *inode,
}
}
void ext4_ind_truncate(struct inode *inode)
void ext4_ind_truncate(handle_t *handle, struct inode *inode)
{
handle_t *handle;
struct ext4_inode_info *ei = EXT4_I(inode);
__le32 *i_data = ei->i_data;
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
struct address_space *mapping = inode->i_mapping;
ext4_lblk_t offsets[4];
Indirect chain[4];
Indirect *partial;
__le32 nr = 0;
int n = 0;
ext4_lblk_t last_block, max_block;
loff_t page_len;
unsigned blocksize = inode->i_sb->s_blocksize;
int err;
handle = start_transaction(inode);
if (IS_ERR(handle))
return; /* AKPM: return what? */
last_block = (inode->i_size + blocksize-1)
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
if (inode->i_size % PAGE_CACHE_SIZE != 0) {
page_len = PAGE_CACHE_SIZE -
(inode->i_size & (PAGE_CACHE_SIZE - 1));
err = ext4_discard_partial_page_buffers(handle,
mapping, inode->i_size, page_len, 0);
if (err)
goto out_stop;
}
if (last_block != max_block) {
n = ext4_block_to_path(inode, last_block, offsets, NULL);
if (n == 0)
goto out_stop; /* error */
return;
}
/*
* OK. This truncate is going to happen. We add the inode to the
* orphan list, so that if this truncate spans multiple transactions,
* and we crash, we will resume the truncate when the filesystem
* recovers. It also marks the inode dirty, to catch the new size.
*
* Implication: the file must always be in a sane, consistent
* truncatable state while each transaction commits.
*/
if (ext4_orphan_add(handle, inode))
goto out_stop;
/*
* From here we block out all ext4_get_block() callers who want to
* modify the block allocation tree.
*/
down_write(&ei->i_data_sem);
ext4_discard_preallocations(inode);
ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
/*
@ -1296,7 +1241,7 @@ void ext4_ind_truncate(struct inode *inode)
* It is unnecessary to free any data blocks if last_block is
* equal to the indirect block limit.
*/
goto out_unlock;
return;
} else if (n == 1) { /* direct blocks */
ext4_free_data(handle, inode, NULL, i_data+offsets[0],
i_data + EXT4_NDIR_BLOCKS);
@ -1356,31 +1301,6 @@ do_indirects:
case EXT4_TIND_BLOCK:
;
}
out_unlock:
up_write(&ei->i_data_sem);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
/*
* In a multi-transaction truncate, we only make the final transaction
* synchronous
*/
if (IS_SYNC(inode))
ext4_handle_sync(handle);
out_stop:
/*
* If this was a simple ftruncate(), and the file will remain alive
* then we need to clear up the orphan record which we created above.
* However, if this was a real unlink then we were called by
* ext4_delete_inode(), and we allow that function to clean up the
* orphan info for us.
*/
if (inode->i_nlink)
ext4_orphan_del(handle, inode);
ext4_journal_stop(handle);
trace_ext4_truncate_exit(inode);
}
static int free_hole_blocks(handle_t *handle, struct inode *inode,

74
fs/ext4/inode.c
View File

@ -3738,9 +3738,9 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
stop_block);
ext4_discard_preallocations(inode);
up_write(&EXT4_I(inode)->i_data_sem);
if (IS_SYNC(inode))
ext4_handle_sync(handle);
up_write(&EXT4_I(inode)->i_data_sem);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
out_stop:
@ -3782,6 +3782,12 @@ out_mutex:
*/
void ext4_truncate(struct inode *inode)
{
struct ext4_inode_info *ei = EXT4_I(inode);
unsigned int credits;
handle_t *handle;
struct address_space *mapping = inode->i_mapping;
loff_t page_len;
trace_ext4_truncate_enter(inode);
if (!ext4_can_truncate(inode))
@ -3800,10 +3806,72 @@ void ext4_truncate(struct inode *inode)
return;
}
/*
* finish any pending end_io work so we won't run the risk of
* converting any truncated blocks to initialized later
*/
ext4_flush_unwritten_io(inode);
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
ext4_ext_truncate(inode);
credits = ext4_writepage_trans_blocks(inode);
else
ext4_ind_truncate(inode);
credits = ext4_blocks_for_truncate(inode);
handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
if (IS_ERR(handle)) {
ext4_std_error(inode->i_sb, PTR_ERR(handle));
return;
}
if (inode->i_size % PAGE_CACHE_SIZE != 0) {
page_len = PAGE_CACHE_SIZE -
(inode->i_size & (PAGE_CACHE_SIZE - 1));
if (ext4_discard_partial_page_buffers(handle,
mapping, inode->i_size, page_len, 0))
goto out_stop;
}
/*
* We add the inode to the orphan list, so that if this
* truncate spans multiple transactions, and we crash, we will
* resume the truncate when the filesystem recovers. It also
* marks the inode dirty, to catch the new size.
*
* Implication: the file must always be in a sane, consistent
* truncatable state while each transaction commits.
*/
if (ext4_orphan_add(handle, inode))
goto out_stop;
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode);
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
ext4_ext_truncate(handle, inode);
else
ext4_ind_truncate(handle, inode);
up_write(&ei->i_data_sem);
if (IS_SYNC(inode))
ext4_handle_sync(handle);
out_stop:
/*
* If this was a simple ftruncate() and the file will remain alive,
* then we need to clear up the orphan record which we created above.
* However, if this was a real unlink then we were called by
* ext4_delete_inode(), and we allow that function to clean up the
* orphan info for us.
*/
if (inode->i_nlink)
ext4_orphan_del(handle, inode);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
ext4_journal_stop(handle);
trace_ext4_truncate_exit(inode);
}