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Date: Sun, 24 Mar 2013 20:06:52 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH 5/7] 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@....edu>
---
fs/ext4/ext4.h | 4 +--
fs/ext4/extents.c | 60 +------------------------------------
fs/ext4/indirect.c | 88 +++---------------------------------------------------
fs/ext4/inode.c | 72 ++++++++++++++++++++++++++++++++++++++++++--
4 files changed, 77 insertions(+), 147 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0649253..d05ba38 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -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 *);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 8f6b3de..57cb4b7 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4254,48 +4254,13 @@ 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,
* because page truncation is enough.
@@ -4310,29 +4275,6 @@ 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,
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 926028c..80a798b 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -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,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 11cf505..ab20015 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3783,6 +3783,12 @@ 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))
@@ -3801,10 +3807,72 @@ 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);
}
--
1.7.12.rc0.22.gcdd159b
--
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