linux.git/fs/fuse/dir.c, branch v5.7

fuse: Support RENAME_WHITEOUT flag

2020-02-06T15:39:28+00:00

Allow fuse to pass RENAME_WHITEOUT to fuse server.  Overlayfs on top of
virtiofs uses RENAME_WHITEOUT.

Without this patch renaming a directory in overlayfs (dir is on lower)
fails with -EINVAL. With this patch it works.

Signed-off-by: Vivek Goyal 
Signed-off-by: Miklos Szeredi

fuse: verify nlink

2019-11-12T10:49:04+00:00

When adding a new hard link, make sure that i_nlink doesn't overflow.

Fixes: ac45d61357e8 ("fuse: fix nlink after unlink")
Cc:  # v3.4
Signed-off-by: Miklos Szeredi

fuse: verify attributes

2019-11-12T10:49:04+00:00

If a filesystem returns negative inode sizes, future reads on the file were
causing the cpu to spin on truncate_pagecache.

Create a helper to validate the attributes.  This now does two things:

 - check the file mode
 - check if the file size fits in i_size without overflowing

Reported-by: Arijit Banerjee 
Fixes: d8a5ba45457e ("[PATCH] FUSE - core")
Cc:  # v2.6.14
Signed-off-by: Miklos Szeredi

fuse: flush dirty data/metadata before non-truncate setattr

2019-10-23T12:26:37+00:00

If writeback cache is enabled, then writes might get reordered with
chmod/chown/utimes.  The problem with this is that performing the write in
the fuse daemon might itself change some of these attributes.  In such case
the following sequence of operations will result in file ending up with the
wrong mode, for example:

  int fd = open ("suid", O_WRONLY|O_CREAT|O_EXCL);
  write (fd, "1", 1);
  fchown (fd, 0, 0);
  fchmod (fd, 04755);
  close (fd);

This patch fixes this by flushing pending writes before performing
chown/chmod/utimes.

Reported-by: Giuseppe Scrivano 
Tested-by: Giuseppe Scrivano 
Fixes: 4d99ff8f12eb ("fuse: Turn writeback cache on")
Cc:  # v3.15+
Signed-off-by: Miklos Szeredi

fuse: don't advise readdirplus for negative lookup

2019-10-21T13:57:07+00:00

If the FUSE_READDIRPLUS_AUTO feature is enabled, then lookups on a
directory before/during readdir are used as an indication that READDIRPLUS
should be used instead of READDIR.  However if the lookup turns out to be
negative, then selecting READDIRPLUS makes no sense.

Signed-off-by: Miklos Szeredi

fuse: kmemcg account fs data

2019-09-24T13:28:01+00:00

account per-file, dentry, and inode data

blockdev/superblock and temporary per-request data was left alone, as
this usually isn't accounted

Reviewed-by: Shakeel Butt 
Signed-off-by: Khazhismel Kumykov 
Signed-off-by: Miklos Szeredi

fuse: on 64-bit store time in d_fsdata directly

2019-09-24T13:28:01+00:00

Implements the optimization noted in commit f75fdf22b0a8 ("fuse: don't
use ->d_time"), as the additional memory can be significant.  (In
particular, on SLAB configurations this 8-byte alloc becomes 32 bytes).
Per-dentry, this can consume significant memory.

Reviewed-by: Shakeel Butt 
Signed-off-by: Khazhismel Kumykov 
Signed-off-by: Miklos Szeredi

fuse: delete dentry if timeout is zero

2019-09-12T12:59:41+00:00

Don't hold onto dentry in lru list if need to re-lookup it anyway at next
access.  Only do this if explicitly enabled, otherwise it could result in
performance regression.

More advanced version of this patch would periodically flush out dentries
from the lru which have gone stale.

Signed-off-by: Miklos Szeredi

fuse: convert readlink to simple api

2019-09-10T14:29:49+00:00

Also turn BUG_ON into gracefully recovered WARN_ON.

Signed-off-by: Miklos Szeredi

fuse: flatten 'struct fuse_args'

2019-09-10T14:29:48+00:00

...to make future expansion simpler.  The hiearachical structure is a
historical thing that does not serve any practical purpose.

The generated code is excatly the same before and after the patch.

Signed-off-by: Miklos Szeredi