Merge tag 'vfs-6.16-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull misc vfs updates from Christian Brauner:
 "This contains the usual selections of misc updates for this cycle.

  Features:

   - Use folios for symlinks in the page cache

     FUSE already uses folios for its symlinks. Mirror that conversion
     in the generic code and the NFS code. That lets us get rid of a few
     folio->page->folio conversions in this path, and some of the few
     remaining users of read_cache_page() / read_mapping_page()

   - Try and make a few filesystem operations killable on the VFS
     inode->i_mutex level

   - Add sysctl vfs_cache_pressure_denom for bulk file operations

     Some workloads need to preserve more dentries than we currently
     allow through out sysctl interface

     A HDFS servers with 12 HDDs per server, on a HDFS datanode startup
     involves scanning all files and caching their metadata (including
     dentries and inodes) in memory. Each HDD contains approximately 2
     million files, resulting in a total of ~20 million cached dentries
     after initialization

     To minimize dentry reclamation, they set vfs_cache_pressure to 1.
     Despite this configuration, memory pressure conditions can still
     trigger reclamation of up to 50% of cached dentries, reducing the
     cache from 20 million to approximately 10 million entries. During
     the subsequent cache rebuild period, any HDFS datanode restart
     operation incurs substantial latency penalties until full cache
     recovery completes

     To maintain service stability, more dentries need to be preserved
     during memory reclamation. The current minimum reclaim ratio (1/100
     of total dentries) remains too aggressive for such workload. This
     patch introduces vfs_cache_pressure_denom for more granular cache
     pressure control

     The configuration [vfs_cache_pressure=1,
     vfs_cache_pressure_denom=10000] effectively maintains the full 20
     million dentry cache under memory pressure, preventing datanode
     restart performance degradation

   - Avoid some jumps in inode_permission() using likely()/unlikely()

   - Avid a memory access which is most likely a cache miss when
     descending into devcgroup_inode_permission()

   - Add fastpath predicts for stat() and fdput()

   - Anonymous inodes currently don't come with a proper mode causing
     issues in the kernel when we want to add useful VFS debug assert.
     Fix that by giving them a proper mode and masking it off when we
     report it to userspace which relies on them not having any mode

   - Anonymous inodes currently allow to change inode attributes because
     the VFS falls back to simple_setattr() if i_op->setattr isn't
     implemented. This means the ownership and mode for every single
     user of anon_inode_inode can be changed. Block that as it's either
     useless or actively harmful. If specific ownership is needed the
     respective subsystem should allocate anonymous inodes from their
     own private superblock

   - Raise SB_I_NODEV and SB_I_NOEXEC on the anonymous inode superblock

   - Add proper tests for anonymous inode behavior

   - Make it easy to detect proper anonymous inodes and to ensure that
     we can detect them in codepaths such as readahead()

  Cleanups:

   - Port pidfs to the new anon_inode_{g,s}etattr() helpers

   - Try to remove the uselib() system call

   - Add unlikely branch hint return path for poll

   - Add unlikely branch hint on return path for core_sys_select

   - Don't allow signals to interrupt getdents copying for fuse

   - Provide a size hint to dir_context for during readdir()

   - Use writeback_iter directly in mpage_writepages

   - Update compression and mtime descriptions in initramfs
     documentation

   - Update main netfs API document

   - Remove useless plus one in super_cache_scan()

   - Remove unnecessary NULL-check guards during setns()

   - Add separate separate {get,put}_cgroup_ns no-op cases

  Fixes:

   - Fix typo in root= kernel parameter description

   - Use KERN_INFO for infof()|info_plog()|infofc()

   - Correct comments of fs_validate_description()

   - Mark an unlikely if condition with unlikely() in
     vfs_parse_monolithic_sep()

   - Delete macro fsparam_u32hex()

   - Remove unused and problematic validate_constant_table()

   - Fix potential unsigned integer underflow in fs_name()

   - Make file-nr output the total allocated file handles"

* tag 'vfs-6.16-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (43 commits)
  fs: Pass a folio to page_put_link()
  nfs: Use a folio in nfs_get_link()
  fs: Convert __page_get_link() to use a folio
  fs/read_write: make default_llseek() killable
  fs/open: make do_truncate() killable
  fs/open: make chmod_common() and chown_common() killable
  include/linux/fs.h: add inode_lock_killable()
  readdir: supply dir_context.count as readdir buffer size hint
  vfs: Add sysctl vfs_cache_pressure_denom for bulk file operations
  fuse: don't allow signals to interrupt getdents copying
  Documentation: fix typo in root= kernel parameter description
  include/cgroup: separate {get,put}_cgroup_ns no-op case
  kernel/nsproxy: remove unnecessary guards
  fs: use writeback_iter directly in mpage_writepages
  fs: remove useless plus one in super_cache_scan()
  fs: add S_ANON_INODE
  fs: remove uselib() system call
  device_cgroup: avoid access to ->i_rdev in the common case in devcgroup_inode_permission()
  fs/fs_parse: Remove unused and problematic validate_constant_table()
  fs: touch up predicts in inode_permission()
  ...

Author: torvalds

Documentation/admin-guide/kernel-parameters.txt

@@ -6268,7 +6268,7 @@
 			port and the regular usb controller gets disabled.
 
 	root=		[KNL] Root filesystem
-			Usually this a a block device specifier of some kind,
+			Usually this is a block device specifier of some kind,
 			see the early_lookup_bdev comment in
 			block/early-lookup.c for details.
 			Alternatively this can be "ram" for the legacy initial

Documentation/admin-guide/sysctl/vm.rst

@@ -75,6 +75,7 @@ Currently, these files are in /proc/sys/vm:
 - unprivileged_userfaultfd
 - user_reserve_kbytes
 - vfs_cache_pressure
+- vfs_cache_pressure_denom
 - watermark_boost_factor
 - watermark_scale_factor
 - zone_reclaim_mode
@@ -1017,19 +1018,28 @@ vfs_cache_pressure
 This percentage value controls the tendency of the kernel to reclaim
 the memory which is used for caching of directory and inode objects.
 
-At the default value of vfs_cache_pressure=100 the kernel will attempt to
-reclaim dentries and inodes at a "fair" rate with respect to pagecache and
-swapcache reclaim.  Decreasing vfs_cache_pressure causes the kernel to prefer
-to retain dentry and inode caches. When vfs_cache_pressure=0, the kernel will
-never reclaim dentries and inodes due to memory pressure and this can easily
-lead to out-of-memory conditions. Increasing vfs_cache_pressure beyond 100
-causes the kernel to prefer to reclaim dentries and inodes.
+At the default value of vfs_cache_pressure=vfs_cache_pressure_denom the kernel
+will attempt to reclaim dentries and inodes at a "fair" rate with respect to
+pagecache and swapcache reclaim.  Decreasing vfs_cache_pressure causes the
+kernel to prefer to retain dentry and inode caches. When vfs_cache_pressure=0,
+the kernel will never reclaim dentries and inodes due to memory pressure and
+this can easily lead to out-of-memory conditions. Increasing vfs_cache_pressure
+beyond vfs_cache_pressure_denom causes the kernel to prefer to reclaim dentries
+and inodes.
 
-Increasing vfs_cache_pressure significantly beyond 100 may have negative
-performance impact. Reclaim code needs to take various locks to find freeable
-directory and inode objects. With vfs_cache_pressure=1000, it will look for
-ten times more freeable objects than there are.
+Increasing vfs_cache_pressure significantly beyond vfs_cache_pressure_denom may
+have negative performance impact. Reclaim code needs to take various locks to
+find freeable directory and inode objects. When vfs_cache_pressure equals
+(10 * vfs_cache_pressure_denom), it will look for ten times more freeable
+objects than there are.
 
+Note: This setting should always be used together with vfs_cache_pressure_denom.
+
+vfs_cache_pressure_denom
+========================
+
+Defaults to 100 (minimum allowed value). Requires corresponding
+vfs_cache_pressure setting to take effect.
 
 watermark_boost_factor
 ======================

Documentation/driver-api/early-userspace/buffer-format.rst

@@ -4,33 +4,39 @@ initramfs buffer format
 
 Al Viro, H. Peter Anvin
 
-Last revision: 2002-01-13
-
-Starting with kernel 2.5.x, the old "initial ramdisk" protocol is
-getting {replaced/complemented} with the new "initial ramfs"
-(initramfs) protocol.  The initramfs contents is passed using the same
-memory buffer protocol used by the initrd protocol, but the contents
+With kernel 2.5.x, the old "initial ramdisk" protocol was complemented
+with an "initial ramfs" protocol.  The initramfs content is passed
+using the same memory buffer protocol used by initrd, but the content
 is different.  The initramfs buffer contains an archive which is
-expanded into a ramfs filesystem; this document details the format of
-the initramfs buffer format.
+expanded into a ramfs filesystem; this document details the initramfs
+buffer format.
 
 The initramfs buffer format is based around the "newc" or "crc" CPIO
 formats, and can be created with the cpio(1) utility.  The cpio
-archive can be compressed using gzip(1).  One valid version of an
-initramfs buffer is thus a single .cpio.gz file.
+archive can be compressed using gzip(1), or any other algorithm provided
+via CONFIG_DECOMPRESS_*.  One valid version of an initramfs buffer is
+thus a single .cpio.gz file.
 
 The full format of the initramfs buffer is defined by the following
 grammar, where::
 
 	*	is used to indicate "0 or more occurrences of"
 	(|)	indicates alternatives
 	+	indicates concatenation
-	GZIP()	indicates the gzip(1) of the operand
+	GZIP()	indicates gzip compression of the operand
+	BZIP2()	indicates bzip2 compression of the operand
+	LZMA()	indicates lzma compression of the operand
+	XZ()	indicates xz compression of the operand
+	LZO()	indicates lzo compression of the operand
+	LZ4()	indicates lz4 compression of the operand
+	ZSTD()	indicates zstd compression of the operand
 	ALGN(n)	means padding with null bytes to an n-byte boundary
 
-	initramfs  := ("\0" | cpio_archive | cpio_gzip_archive)*
+	initramfs := ("\0" | cpio_archive | cpio_compressed_archive)*
 
-	cpio_gzip_archive := GZIP(cpio_archive)
+	cpio_compressed_archive := (GZIP(cpio_archive) | BZIP2(cpio_archive)
+		| LZMA(cpio_archive) | XZ(cpio_archive) | LZO(cpio_archive)
+		| LZ4(cpio_archive) | ZSTD(cpio_archive))
 
 	cpio_archive := cpio_file* + (<nothing> | cpio_trailer)
 
@@ -75,6 +81,8 @@ c_chksum      8 bytes		 Checksum of data field if c_magic is 070702;
 The c_mode field matches the contents of st_mode returned by stat(2)
 on Linux, and encodes the file type and file permissions.
 
+c_mtime is ignored unless CONFIG_INITRAMFS_PRESERVE_MTIME=y is set.
+
 The c_filesize should be zero for any file which is not a regular file
 or symlink.
 

Documentation/filesystems/mount_api.rst

@@ -671,7 +671,6 @@ The members are as follows:
 	fsparam_bool()		fs_param_is_bool
 	fsparam_u32()		fs_param_is_u32
 	fsparam_u32oct()	fs_param_is_u32_octal
-	fsparam_u32hex()	fs_param_is_u32_hex
 	fsparam_s32()		fs_param_is_s32
 	fsparam_u64()		fs_param_is_u64
 	fsparam_enum()		fs_param_is_enum
@@ -753,21 +752,6 @@ process the parameters it is given.
      If a match is found, the corresponding value is returned.  If a match
      isn't found, the not_found value is returned instead.
 
-   * ::
-
-       bool validate_constant_table(const struct constant_table *tbl,
-				    size_t tbl_size,
-				    int low, int high, int special);
-
-     Validate a constant table.  Checks that all the elements are appropriately
-     ordered, that there are no duplicates and that the values are between low
-     and high inclusive, though provision is made for one allowable special
-     value outside of that range.  If no special value is required, special
-     should just be set to lie inside the low-to-high range.
-
-     If all is good, true is returned.  If the table is invalid, errors are
-     logged to the kernel log buffer and false is returned.
-
    * ::
 
        bool fs_validate_description(const char *name,