Merge tag 'vfs-7.4-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull netfs updates from Christian Brauner:
 "This contains the netfs and cachefiles changes for this cycle from
  David.

  Cachefiles learns to cache the most common class of files properly,
  files that are created or truncated, written once sequentially and
  closed. So far it relied on the backing filesystem's idea of what is
  stored and asked with SEEK_DATA and SEEK_HOLE before every read it
  prepared, two seeks per read, and the backing filesystem is free to
  insert or remove runs of zeros which produces false positives and
  false negatives. The object type in the state xattr is now actually
  set to CACHEFILES_CONTENT_{SINGLE,ALL,BACKFS_MAP} instead of zero. For
  files written contiguously the type is ALL, the backing file's i_size
  tracks how much is cached and the object size lives in the xattr, and
  reads skip the seeks entirely. Netfslib queries the cache occupancy
  through a new ->query_occupancy() method that returns up to two
  extents at once, ->prepare_read() only limits the size of a cache read
  anymore and a new ->collect_write() lets the cache update its metadata
  once a contiguous run of writes completes. The state xattr is preset
  when the tmpfile is created so ENOSPC from setxattr can't scrap a
  fully written cache file. Two fixes for this followed, one for resize
  handling where the cache's idea of the size can be stale and one for
  an unset error that hung a request on a failed cache write.

  Preparatory work converts file positions that can't be negative to
  uoff_t, removes the writethrough code whose locking looked like it
  could deadlock with ceph snapshots, makes the deprecated PG_private_2
  support opt-in so mm can get its page bit back, adds helpers for the
  NETFS_RREQ_ALL_QUEUED barriers and adds the cache object id to the
  read and write tracepoints. Plus an unused header removal and two
  documentation fixes"

* tag 'vfs-7.4-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fscache, cachefiles: Fix resize handling
  cachefiles: Fix unset error when calling netfs_prepare_write_failed()
  netfs: remove unused fscache_internal.h header
  cachefiles: Preset the state xattr when creating a new file
  cachefiles: Don't rely on backing fs storage map for most use cases
  netfs: Document the remote size member and its accessors
  cachefiles: Add a tracepoint to log insufficient space errors
  netfs, cachefiles: Add a couple of traces for write failure
  cachefiles: Clean up cachefiles_do_prepare_read()
  netfs: Set subrequest->source at alloc before trace emission
  netfs: Add some functions to wrap the all-queued handling
  netfs: Make deprecated PG_private_2 support opt-in
  netfs: Add the cache object ID to netfs_read/write tracepoints
  netfs: trace: Rejig a couple of the tracepoints
  cachefiles: Fix path of the "debug" module parameter in help paragraph
  netfs: trace: Change the "clear" folio traces to "endwb"
  netfs: Remove the writethrough code
  netfs: Use uoff_t instead of unsigned long long and loff_t

3 files changed, 7 insertions, 4 deletions

diff --git a/Documentation/filesystems/caching/backend-api.rst b/Documentation/filesystems/caching/backend-api.rst
index 3a199fc50828..df837531b3fd 100644
--- a/Documentation/filesystems/caching/backend-api.rst
+++ b/Documentation/filesystems/caching/backend-api.rst
@@ -339,7 +339,7 @@ pointers to methods to allow fscache to request management of the cache:
    * Change the size of a data storage object [mandatory]::
 
 	void (*resize_cookie)(struct netfs_cache_resources *cres,
-			      loff_t new_size);
+			      loff_t new_size, bool shrank);
 
      This method is called to inform the cache backend of a change in size of
      the netfs file due to local truncation.  The cache backend should make all
diff --git a/Documentation/filesystems/caching/netfs-api.rst b/Documentation/filesystems/caching/netfs-api.rst
index 665b27f1556e..3154a1686480 100644
--- a/Documentation/filesystems/caching/netfs-api.rst
+++ b/Documentation/filesystems/caching/netfs-api.rst
@@ -226,7 +226,7 @@ If a network filesystem file is resized locally by truncation, the following
 should be called to notify the cache::
 
 	void fscache_resize_cookie(struct fscache_cookie *cookie,
-				   loff_t new_size);
+				   loff_t new_size, bool shrank);
 
 The caller must have first marked the cookie in-use.  The cookie and the new
 size are passed in and the cache is synchronously resized.  This is expected to
diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst
index a9de281db8ee..215a6621f3d3 100644
--- a/Documentation/filesystems/netfs_library.rst
+++ b/Documentation/filesystems/netfs_library.rst
@@ -195,7 +195,7 @@ structure is defined::
 		struct inode inode;
 		const struct netfs_request_ops *ops;
 		struct fscache_cookie * cache;
-		loff_t remote_i_size;
+		loff_t _remote_i_size;
 		unsigned long flags;
 		...
 	};
@@ -229,11 +229,14 @@ filesystem:
    Local caching cookie, or NULL if no caching is enabled.  This field does not
    exist if fscache is disabled.
 
- * ``remote_i_size``
+ * ``_remote_i_size``
 
    The size of the file on the server.  This differs from inode->i_size if
    local modifications have been made but not yet written back.
 
+   Use netfs_read_remote_i_size() and netfs_write_remote_i_size() to access
+   this field.  Hold inode->i_lock when writing it.
+
  * ``flags``
 
    A set of flags, some of which the filesystem might be interested in: