linux-toradex.git/fs/cachefiles/namei.c, branch v6.1

cachefiles: use vfs_tmpfile_open() helper

2022-09-24T05:00:00+00:00

Use the vfs_tmpfile_open() helper instead of doing tmpfile creation and
opening separately.

The only minor difference is that previously no permission checking was
done, while vfs_tmpfile_open() will call may_open() with zero access mask
(i.e. no access is checked).  Even if this would make a difference with
callers caps (don't see how it could, even in the LSM codepaths) cachfiles
raises caps before performing the tmpfile creation, so this extra
permission check will not result in any regression.

Reviewed-by: Christian Brauner (Microsoft) 
Signed-off-by: Miklos Szeredi

cachefiles: only pass inode to *mark_inode_inuse() helpers

2022-09-24T04:59:59+00:00

The only reason to pass dentry was because of a pr_notice() text.  Move
that to the two callers where it makes sense and add a WARN_ON() to the
third.

file_inode(file) is never NULL on an opened file. Remove check in
cachefiles_unmark_inode_in_use().

Do not open code cachefiles_do_unmark_inode_in_use() in
cachefiles_put_directory().

Signed-off-by: Miklos Szeredi

cachefiles: tmpfile error handling cleanup

2022-09-24T04:59:59+00:00

Separate the error labels from the success path and use 'ret' to store the
error value before jumping to the error label.

Signed-off-by: Miklos Szeredi

cachefiles: notify the user daemon when looking up cookie

2022-05-17T16:11:17+00:00

Fscache/CacheFiles used to serve as a local cache for a remote
networking fs. A new on-demand read mode will be introduced for
CacheFiles, which can boost the scenario where on-demand read semantics
are needed, e.g. container image distribution.

The essential difference between these two modes is seen when a cache
miss occurs: In the original mode, the netfs will fetch the data from
the remote server and then write it to the cache file; in on-demand
read mode, fetching the data and writing it into the cache is delegated
to a user daemon.

As the first step, notify the user daemon when looking up cookie. In
this case, an anonymous fd is sent to the user daemon, through which the
user daemon can write the fetched data to the cache file. Since the user
daemon may move the anonymous fd around, e.g. through dup(), an object
ID uniquely identifying the cache file is also attached.

Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that
the cache file size shall be retrieved at runtime. This helps the
scenario where one cache file contains multiple netfs files, e.g. for
the purpose of deduplication. In this case, netfs itself has no idea the
size of the cache file, whilst the user daemon should give the hint on
it.

Signed-off-by: Jeffle Xu 
Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com
Acked-by: David Howells 
Signed-off-by: Gao Xiang

cachefiles: unmark inode in use in error path

2022-04-08T22:32:30+00:00

Unmark inode in use if error encountered. If the in-use flag leakage
occurs in cachefiles_open_file(), Cachefiles will complain "Inode
already in use" when later another cookie with the same index key is
looked up.

If the in-use flag leakage occurs in cachefiles_create_tmpfile(), though
the "Inode already in use" warning won't be triggered, fix the leakage
anyway.

Reported-by: Gao Xiang 
Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling")
Signed-off-by: Jeffle Xu 
Signed-off-by: David Howells 
cc: linux-cachefs@redhat.com
Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006615.html # v1
Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006618.html # v2

cachefiles: Trace active-mark failure

2022-01-21T21:36:28+00:00

Add a tracepoint to log failure to apply an active mark to a file in
addition to tracing successfully setting and unsetting the mark.

Also include the backing file inode number in the message logged to dmesg.

Signed-off-by: David Howells 
Reviewed-by: Jeff Layton 
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164251404666.3435901.17331742792401482190.stgit@warthog.procyon.org.uk/ # v1

cachefiles: Make some tracepoint adjustments

2022-01-21T21:36:28+00:00

Make some adjustments to tracepoints to make the tracing a bit more
followable:

 (1) Standardise on displaying the backing inode number as "B=" with
     no leading zeros.

 (2) Make the cachefiles_lookup tracepoint log the directory inode number
     as well as the looked-up inode number.

 (3) Add a cachefiles_lookup tracepoint into cachefiles_get_directory() to
     log directory lookup.

 (4) Add a new cachefiles_mkdir tracepoint and use that to log a successful
     mkdir from cachefiles_get_directory().

 (5) Make the cachefiles_unlink and cachefiles_rename tracepoints log the
     inode number of the affected file/dir rather than dentry struct
     pointers.

Signed-off-by: David Howells 
Reviewed-by: Jeff Layton 
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164251403694.3435901.9797725381831316715.stgit@warthog.procyon.org.uk/ # v1

fscache, cachefiles: Display stat of culling events

2022-01-07T13:43:18+00:00

Add a stat counter of culling events whereby the cache backend culls a file
to make space (when asked by cachefilesd in this case) and display in
/proc/fs/fscache/stats.

Signed-off-by: David Howells 
Reviewed-by: Jeff Layton 
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819654165.215744.3797804661644212436.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906961387.143852.9291157239960289090.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967168266.1823006.14436200166581605746.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021567619.640689.4339228906248763197.stgit@warthog.procyon.org.uk/ # v4

fscache, cachefiles: Display stats of no-space events

2022-01-07T13:43:13+00:00

Add stat counters of no-space events that caused caching not to happen and
display in /proc/fs/fscache/stats.

Signed-off-by: David Howells 
Reviewed-by: Jeff Layton 
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819653216.215744.17210522251617386509.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906958369.143852.7257100711818401748.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967166917.1823006.14842444049198947892.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021566184.640689.4417328329632709265.stgit@warthog.procyon.org.uk/ # v4

cachefiles: Implement backing file wrangling

2022-01-07T13:42:40+00:00

Implement the wrangling of backing files, including the following pieces:

(1) Lookup and creation of a file on disk, using a tmpfile if the file
isn't yet present. The file is then opened, sized for DIO and the
file handle is attached to the cachefiles_object struct. The inode is
marked to indicate that it's in use by a kernel service.

(2) Invalidation of an object, creating a tmpfile and switching the file
pointer in the cachefiles object.

(3) Committing a file to disk, including setting the coherency xattr on it
and, if necessary, creating a hard link to it.

Note that this would be a good place to use Omar Sandoval's vfs_link()
with AT_LINK_REPLACE[1] as I may have to unlink an old file before I
can link a tmpfile into place.

(4) Withdrawal of open objects when a cache is being withdrawn or a cookie
is relinquished. This involves committing or discarding the file.

Changes
=======
ver #2:
- Fix logging of wrong error[1].

Signed-off-by: David Howells
Reviewed-by: Jeff Layton
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1]
Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4