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fuse: invalidate inode attr in writeback cache mode

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Under writeback mode, inode->i_blocks is not updated, making utils du
read st.blocks as 0.

For example, when using virtiofs (cache=always & nondax mode) with
writeback_cache enabled, writing a new file and check its disk usage
with du, du reports 0 usage.

  # uname -r
  5.6.0-rc6+
  # mount -t virtiofs virtiofs /mnt/virtiofs
  # rm -f /mnt/virtiofs/testfile

  # create new file and do extend write
  # xfs_io -fc "pwrite 0 4k" /mnt/virtiofs/testfile
  wrote 4096/4096 bytes at offset 0
  4 KiB, 1 ops; 0.0001 sec (28.103 MiB/sec and 7194.2446 ops/sec)
  # du -k /mnt/virtiofs/testfile
  0               <==== disk usage is 0
  # stat -c %s,%b /mnt/virtiofs/testfile
  4096,0          <==== i_size is correct, but st_blocks is 0

Fix it by invalidating attr in fuse_flush(), so we get up-to-date attr
from server on next getattr.

Signed-off-by: Eryu Guan <eguan@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Eryu Guan 2020-05-12 10:29:04 +08:00 committed by Miklos Szeredi
parent 75d892588e
commit cf576c58b3
1 changed files with 10 additions and 1 deletions
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11
fs/fuse/file.c
View File

@ -445,8 +445,9 @@ static int fuse_flush(struct file *file, fl_owner_t id)
if (is_bad_inode(inode))
return -EIO;
err = 0;
if (fc->no_flush)
return 0;
goto inval_attr_out;
err = write_inode_now(inode, 1);
if (err)
@ -475,6 +476,14 @@ static int fuse_flush(struct file *file, fl_owner_t id)
fc->no_flush = 1;
err = 0;
}
inval_attr_out:
/*
* In memory i_blocks is not maintained by fuse, if writeback cache is
* enabled, i_blocks from cached attr may not be accurate.
*/
if (!err && fc->writeback_cache)
fuse_invalidate_attr(inode);
return err;
}