| Message ID | 20190409030158.136316-1-houtao1@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fat: issue flush after the writeback of FAT | expand |
On Tue, Apr 09, 2019 at 11:01:58AM +0800, Hou Tao wrote: > fsync() needs to make sure the data & meta-data of file are persistent > after the return of fsync(), even when a power-failure occurs later. > In the case of fat-fs, the FAT belongs to the meta-data of file, > so we need to issue a flush after the writeback of FAT instead before. > > Also bail out early when any stage of fsync fails. > > Signed-off-by: Hou Tao <houtao1@huawei.com> > --- > fs/fat/file.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/fs/fat/file.c b/fs/fat/file.c > index b3bed32946b1..0e3ed79fcc3f 100644 > --- a/fs/fat/file.c > +++ b/fs/fat/file.c > @@ -193,12 +193,17 @@ static int fat_file_release(struct inode *inode, struct file *filp) > int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) > { > struct inode *inode = filp->f_mapping->host; > - int res, err; > + int err; > + > + err = __generic_file_fsync(filp, start, end, datasync); > + if (err) > + return err; > > - res = generic_file_fsync(filp, start, end, datasync); > err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping); Huh. I would've thought that flushing the FAT would also be required at the end of a WB_SYNC_ALL (aka data integrity) writepages call? The patch itself seems good, though. --D > + if (err) > + return err; > > - return res ? res : err; > + return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); > } > > > -- > 2.16.2.dirty >
Hou Tao <houtao1@huawei.com> writes: > fsync() needs to make sure the data & meta-data of file are persistent > after the return of fsync(), even when a power-failure occurs later. > In the case of fat-fs, the FAT belongs to the meta-data of file, > so we need to issue a flush after the writeback of FAT instead before. > > Also bail out early when any stage of fsync fails. > > Signed-off-by: Hou Tao <houtao1@huawei.com> Looks good. Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> > --- > fs/fat/file.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/fs/fat/file.c b/fs/fat/file.c > index b3bed32946b1..0e3ed79fcc3f 100644 > --- a/fs/fat/file.c > +++ b/fs/fat/file.c > @@ -193,12 +193,17 @@ static int fat_file_release(struct inode *inode, struct file *filp) > int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) > { > struct inode *inode = filp->f_mapping->host; > - int res, err; > + int err; > + > + err = __generic_file_fsync(filp, start, end, datasync); > + if (err) > + return err; > > - res = generic_file_fsync(filp, start, end, datasync); > err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping); > + if (err) > + return err; > > - return res ? res : err; > + return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); > }
"Darrick J. Wong" <darrick.wong@oracle.com> writes: >> + err = __generic_file_fsync(filp, start, end, datasync); >> + if (err) >> + return err; >> >> - res = generic_file_fsync(filp, start, end, datasync); >> err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping); > > Huh. I would've thought that flushing the FAT would also be required > at the end of a WB_SYNC_ALL (aka data integrity) writepages call? In fatfs implement, FAT area is flushed by sync_mapping_buffers(fat_inode). (FAT buffer is dirtied only by using bh->b_assoc_map to fat_inode) Thanks.
diff --git a/fs/fat/file.c b/fs/fat/file.c index b3bed32946b1..0e3ed79fcc3f 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -193,12 +193,17 @@ static int fat_file_release(struct inode *inode, struct file *filp) int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) { struct inode *inode = filp->f_mapping->host; - int res, err; + int err; + + err = __generic_file_fsync(filp, start, end, datasync); + if (err) + return err; - res = generic_file_fsync(filp, start, end, datasync); err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping); + if (err) + return err; - return res ? res : err; + return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); }
fsync() needs to make sure the data & meta-data of file are persistent after the return of fsync(), even when a power-failure occurs later. In the case of fat-fs, the FAT belongs to the meta-data of file, so we need to issue a flush after the writeback of FAT instead before. Also bail out early when any stage of fsync fails. Signed-off-by: Hou Tao <houtao1@huawei.com> --- fs/fat/file.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)