Original patch rh6/diff-ext4-fallocate-mode-convert-and-extend-v3
The patch introduces new fallocate mode: FALLOC_FL_CONVERT_AND_EXTEND. It
performs two actions:
- convert all uninitialized extends in the range <offset, offset + length>
- set i_size to "offset + length".
The feature will be used by ploop io_direct module for optimizing submit_alloc
path.
Changed in v2 (thanks to Dima for findings):
- moved journal start/stop into while(){...}
- added update_fsync_trans call
Changed in v3 (thanks again to Dima for findings):
- protected operations on extnet tree by i_data_sem
https://jira.sw.ru/browse/PSBM-22381
Signed-off-by: Dmitry Monakhov <dmonak...@openvz.org>
---
fs/ext4/extents.c | 135 ++++++++++++++++++++++++++++++++++++++++++-
include/uapi/linux/falloc.h | 3 +
2 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 606a47c..dfa4e7a 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4448,6 +4448,131 @@ static void ext4_falloc_update_inode(struct inode
*inode,
}
+
+static int ext4_convert_and_extend_locked(struct inode *inode, loff_t offset,
+ loff_t len)
+{
+ struct ext4_ext_path *path = NULL;
+ loff_t new_size = offset + len;
+ ext4_lblk_t iblock = offset >> inode->i_blkbits;
+ ext4_lblk_t new_iblock = new_size >> inode->i_blkbits;
+ unsigned int max_blocks = new_iblock - iblock;
+ handle_t *handle;
+ unsigned int credits;
+ int err = 0;
+ int ret = 0;
+
+ if ((loff_t)iblock << inode->i_blkbits != offset ||
+ (loff_t)new_iblock << inode->i_blkbits != new_size)
+ return -EINVAL;
+
+ while (max_blocks > 0) {
+ struct ext4_extent *ex;
+ ext4_lblk_t ee_block;
+ ext4_fsblk_t ee_start;
+ unsigned short ee_len;
+ int depth;
+
+ /*
+ * credits to insert 1 extents into extent tree
+ */
+ credits = ext4_chunk_trans_blocks(inode, max_blocks);
+ handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ down_write((&EXT4_I(inode)->i_data_sem));
+
+ /* find extent for this block */
+ path = ext4_ext_find_extent(inode, iblock, NULL);
+ if (IS_ERR(path)) {
+ err = PTR_ERR(path);
+ goto done;
+ }
+
+ depth = ext_depth(inode);
+ ex = path[depth].p_ext;
+ BUG_ON(ex == NULL && depth != 0);
+
+ if (ex == NULL) {
+ err = -ENOENT;
+ goto done;
+ }
+
+ ee_block = le32_to_cpu(ex->ee_block);
+ ee_start = ext4_ext_pblock(ex);
+ ee_len = ext4_ext_get_actual_len(ex);
+ if (!in_range(iblock, ee_block, ee_len)) {
+ err = -ERANGE;
+ goto done;
+ }
+
+ if (ext4_ext_is_uninitialized(ex)) {
+ struct ext4_map_blocks map = {0};
+
+ map.m_lblk = iblock;
+ map.m_len = max_blocks;
+ err = ext4_convert_unwritten_extents_endio(handle,
inode,
+ &map,
+ path);
+ if (err < 0)
+ goto done;
+
+ ext4_update_inode_fsync_trans(handle, inode, 1);
+ err = check_eofblocks_fl(handle, inode, iblock, path,
+ max_blocks);
+ if (err)
+ goto done;
+ }
+
+
+ up_write((&EXT4_I(inode)->i_data_sem));
+
+ iblock += ee_len;
+ max_blocks -= (ee_len < max_blocks) ? ee_len : max_blocks;
+
+ if (!max_blocks && new_size > i_size_read(inode)) {
+ i_size_write(inode, new_size);
+ ext4_update_i_disksize(inode, new_size);
+ }
+
+ ret = ext4_mark_inode_dirty(handle, inode);
+done:
+ if (err)
+ up_write((&EXT4_I(inode)->i_data_sem));
+ else
+ err = ret;
+
+ if (path) {
+ ext4_ext_drop_refs(path);
+ kfree(path);
+ }
+
+ ret = ext4_journal_stop(handle);
+ if (!err && ret)
+ err = ret;
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int ext4_convert_and_extend(struct inode *inode, loff_t offset,
+ loff_t len)
+{
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ mutex_lock(&inode->i_mutex);
+ err = ext4_convert_and_extend_locked(inode, offset, len);
+ mutex_unlock(&inode->i_mutex);
+
+ return err;
+}
+
/*
* preallocate space for a file. This implements ext4's fallocate file
* operation, which gets called from sys_fallocate system call.
@@ -4474,20 +4599,26 @@ long ext4_fallocate(struct file *file, int mode, loff_t
offset, loff_t len)
*/
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
return -EOPNOTSUPP;
-
+
/* Return error if mode is not supported */
- if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
+ FALLOC_FL_CONVERT_AND_EXTEND))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
return ext4_punch_hole(file, offset, len);
+ if (mode & FALLOC_FL_CONVERT_AND_EXTEND)
+ return ext4_convert_and_extend(inode, offset, len);
+
ret = ext4_convert_inline_data(inode);
if (ret)
return ret;
trace_ext4_fallocate_enter(inode, offset, len, mode);
map.m_lblk = offset >> blkbits;
+
+
/*
* We can't just convert len to max_blocks because
* If blocksize = 4096 offset = 3072 and len = 2048
diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h
index 990c4cc..17b618f 100644
--- a/include/uapi/linux/falloc.h
+++ b/include/uapi/linux/falloc.h
@@ -4,6 +4,9 @@
#define FALLOC_FL_KEEP_SIZE 0x01 /* default is extend size */
#define FALLOC_FL_PUNCH_HOLE 0x02 /* de-allocates range */
#define FALLOC_FL_NO_HIDE_STALE 0x04 /* reserved codepoint */
+#define FALLOC_FL_CONVERT_AND_EXTEND 0x100 /* mark extents as initialized
+ * and extend i_size */
+
#endif /* _UAPI_FALLOC_H_ */
--
1.7.1
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