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f2fs: do not preallocate blocks which has wrong buffer

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Sheng Yong reports needless preallocation if write(small_buffer, large_size)
is called.

In that case, f2fs preallocates large_size, but vfs returns early due to
small_buffer size. Let's detect it before preallocation phase in f2fs.

Reported-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim 2017-01-13 13:12:29 -08:00
parent dcc9165dbf
commit dc91de78e5
3 changed files with 13 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/f2fs/data.c
View File

@ -749,6 +749,9 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
struct f2fs_map_blocks map;
int err = 0;
if (is_inode_flag_set(inode, FI_NO_PREALLOC))
return 0;
map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);
map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from));
if (map.m_len > map.m_lblk)
@ -1653,7 +1656,8 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
* we already allocated all the blocks, so we don't need to get
* the block addresses when there is no need to fill the page.
*/
if (!f2fs_has_inline_data(inode) && len == PAGE_SIZE)
if (!f2fs_has_inline_data(inode) && len == PAGE_SIZE &&
!is_inode_flag_set(inode, FI_NO_PREALLOC))
return 0;
if (f2fs_has_inline_data(inode) ||

1
fs/f2fs/f2fs.h
View File

@ -1665,6 +1665,7 @@ enum {
FI_INLINE_DOTS, /* indicate inline dot dentries */
FI_DO_DEFRAG, /* indicate defragment is running */
FI_DIRTY_FILE, /* indicate regular/symlink has dirty pages */
FI_NO_PREALLOC, /* indicate skipped preallocated blocks */
};
static inline void __mark_inode_dirty_flag(struct inode *inode,

8
fs/f2fs/file.c
View File

@ -20,6 +20,7 @@
#include <linux/uaccess.h>
#include <linux/mount.h>
#include <linux/pagevec.h>
#include <linux/uio.h>
#include <linux/uuid.h>
#include <linux/file.h>
@ -2258,8 +2259,12 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
inode_lock(inode);
ret = generic_write_checks(iocb, from);
if (ret > 0) {
int err = f2fs_preallocate_blocks(iocb, from);
int err;
if (iov_iter_fault_in_readable(from, iov_iter_count(from)))
set_inode_flag(inode, FI_NO_PREALLOC);
err = f2fs_preallocate_blocks(iocb, from);
if (err) {
inode_unlock(inode);
return err;
@ -2267,6 +2272,7 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
blk_start_plug(&plug);
ret = __generic_file_write_iter(iocb, from);
blk_finish_plug(&plug);
clear_inode_flag(inode, FI_NO_PREALLOC);
}
inode_unlock(inode);