linux/fs/afs/super.c
Linus Torvalds 8834147f95 fscache rewrite
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Merge tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull fscache rewrite from David Howells:
 "This is a set of patches that rewrites the fscache driver and the
  cachefiles driver, significantly simplifying the code compared to
  what's upstream, removing the complex operation scheduling and object
  state machine in favour of something much smaller and simpler.

  The series is structured such that the first few patches disable
  fscache use by the network filesystems using it, remove the cachefiles
  driver entirely and as much of the fscache driver as can be got away
  with without causing build failures in the network filesystems.

  The patches after that recreate fscache and then cachefiles,
  attempting to add the pieces in a logical order. Finally, the
  filesystems are reenabled and then the very last patch changes the
  documentation.

  [!] Note: I have dropped the cifs patch for the moment, leaving local
      caching in cifs disabled. I've been having trouble getting that
      working. I think I have it done, but it needs more testing (there
      seem to be some test failures occurring with v5.16 also from
      xfstests), so I propose deferring that patch to the end of the
      merge window.

  WHY REWRITE?
  ============

  Fscache's operation scheduling API was intended to handle sequencing
  of cache operations, which were all required (where possible) to run
  asynchronously in parallel with the operations being done by the
  network filesystem, whilst allowing the cache to be brought online and
  offline and to interrupt service for invalidation.

  With the advent of the tmpfile capacity in the VFS, however, an
  opportunity arises to do invalidation much more simply, without having
  to wait for I/O that's actually in progress: Cachefiles can simply
  create a tmpfile, cut over the file pointer for the backing object
  attached to a cookie and abandon the in-progress I/O, dismissing it
  upon completion.

  Future work here would involve using Omar Sandoval's vfs_link() with
  AT_LINK_REPLACE[1] to allow an extant file to be displaced by a new
  hard link from a tmpfile as currently I have to unlink the old file
  first.

  These patches can also simplify the object state handling as I/O
  operations to the cache don't all have to be brought to a stop in
  order to invalidate a file. To that end, and with an eye on to writing
  a new backing cache model in the future, I've taken the opportunity to
  simplify the indexing structure.

  I've separated the index cookie concept from the file cookie concept
  by C type now. The former is now called a "volume cookie" (struct
  fscache_volume) and there is a container of file cookies. There are
  then just the two levels. All the index cookie levels are collapsed
  into a single volume cookie, and this has a single printable string as
  a key. For instance, an AFS volume would have a key of something like
  "afs,example.com,1000555", combining the filesystem name, cell name
  and volume ID. This is freeform, but must not have '/' chars in it.

  I've also eliminated all pointers back from fscache into the network
  filesystem. This required the duplication of a little bit of data in
  the cookie (cookie key, coherency data and file size), but it's not
  actually that much. This gets rid of problems with making sure we keep
  netfs data structures around so that the cache can access them.

  These patches mean that most of the code that was in the drivers
  before is simply gone and those drivers are now almost entirely new
  code. That being the case, there doesn't seem any particular reason to
  try and maintain bisectability across it. Further, there has to be a
  point in the middle where things are cut over as there's a single
  point everything has to go through (ie. /dev/cachefiles) and it can't
  be in use by two drivers at once.

  ISSUES YET OUTSTANDING
  ======================

  There are some issues still outstanding, unaddressed by this patchset,
  that will need fixing in future patchsets, but that don't stop this
  series from being usable:

  (1) The cachefiles driver needs to stop using the backing filesystem's
      metadata to store information about what parts of the cache are
      populated. This is not reliable with modern extent-based
      filesystems.

      Fixing this is deferred to a separate patchset as it involves
      negotiation with the network filesystem and the VM as to how much
      data to download to fulfil a read - which brings me on to (2)...

  (2) NFS (and CIFS with the dropped patch) do not take account of how
      the cache would like I/O to be structured to meet its granularity
      requirements. Previously, the cache used page granularity, which
      was fine as the network filesystems also dealt in page
      granularity, and the backing filesystem (ext4, xfs or whatever)
      did whatever it did out of sight. However, we now have folios to
      deal with and the cache will now have to store its own metadata to
      track its contents.

      The change I'm looking at making for cachefiles is to store
      content bitmaps in one or more xattrs and making a bit in the map
      correspond to something like a 256KiB block. However, the size of
      an xattr and the fact that they have to be read/updated in one go
      means that I'm looking at covering 1GiB of data per 512-byte map
      and storing each map in an xattr. Cachefiles has the potential to
      grow into a fully fledged filesystem of its very own if I'm not
      careful.

      However, I'm also looking at changing things even more radically
      and going to a different model of how the cache is arranged and
      managed - one that's more akin to the way, say, openafs does
      things - which brings me on to (3)...

  (3) The way cachefilesd does culling is very inefficient for large
      caches and it would be better to move it into the kernel if I can
      as cachefilesd has to keep asking the kernel if it can cull a
      file. Changing the way the backend works would allow this to be
      addressed.

  BITS THAT MAY BE CONTROVERSIAL
  ==============================

  There are some bits I've added that may be controversial:

  (1) I've provided a flag, S_KERNEL_FILE, that cachefiles uses to check
      if a files is already being used by some other kernel service
      (e.g. a duplicate cachefiles cache in the same directory) and
      reject it if it is. This isn't entirely necessary, but it helps
      prevent accidental data corruption.

      I don't want to use S_SWAPFILE as that has other effects, but
      quite possibly swapon() should set S_KERNEL_FILE too.

      Note that it doesn't prevent userspace from interfering, though
      perhaps it should. (I have made it prevent a marked directory from
      being rmdir-able).

  (2) Cachefiles wants to keep the backing file for a cookie open whilst
      we might need to write to it from network filesystem writeback.
      The problem is that the network filesystem unuses its cookie when
      its file is closed, and so we have nothing pinning the cachefiles
      file open and it will get closed automatically after a short time
      to avoid EMFILE/ENFILE problems.

      Reopening the cache file, however, is a problem if this is being
      done due to writeback triggered by exit(). Some filesystems will
      oops if we try to open a file in that context because they want to
      access current->fs or suchlike.

      To get around this, I added the following:

      (A) An inode flag, I_PINNING_FSCACHE_WB, to be set on a network
          filesystem inode to indicate that we have a usage count on the
          cookie caching that inode.

      (B) A flag in struct writeback_control, unpinned_fscache_wb, that
          is set when __writeback_single_inode() clears the last dirty
          page from i_pages - at which point it clears
          I_PINNING_FSCACHE_WB and sets this flag.

          This has to be done here so that clearing I_PINNING_FSCACHE_WB
          can be done atomically with the check of PAGECACHE_TAG_DIRTY
          that clears I_DIRTY_PAGES.

      (C) A function, fscache_set_page_dirty(), which if it is not set,
          sets I_PINNING_FSCACHE_WB and calls fscache_use_cookie() to
          pin the cache resources.

      (D) A function, fscache_unpin_writeback(), to be called by
          ->write_inode() to unuse the cookie.

      (E) A function, fscache_clear_inode_writeback(), to be called when
          the inode is evicted, before clear_inode() is called. This
          cleans up any lingering I_PINNING_FSCACHE_WB.

      The network filesystem can then use these tools to make sure that
      fscache_write_to_cache() can write locally modified data to the
      cache as well as to the server.

      For the future, I'm working on write helpers for netfs lib that
      should allow this facility to be removed by keeping track of the
      dirty regions separately - but that's incomplete at the moment and
      is also going to be affected by folios, one way or another, since
      it deals with pages"

Link: https://lore.kernel.org/all/510611.1641942444@warthog.procyon.org.uk/
Tested-by: Dominique Martinet <asmadeus@codewreck.org> # 9p
Tested-by: kafs-testing@auristor.com # afs
Tested-by: Jeff Layton <jlayton@kernel.org> # ceph
Tested-by: Dave Wysochanski <dwysocha@redhat.com> # nfs
Tested-by: Daire Byrne <daire@dneg.com> # nfs

* tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (67 commits)
  9p, afs, ceph, nfs: Use current_is_kswapd() rather than gfpflags_allow_blocking()
  fscache: Add a tracepoint for cookie use/unuse
  fscache: Rewrite documentation
  ceph: add fscache writeback support
  ceph: conversion to new fscache API
  nfs: Implement cache I/O by accessing the cache directly
  nfs: Convert to new fscache volume/cookie API
  9p: Copy local writes to the cache when writing to the server
  9p: Use fscache indexing rewrite and reenable caching
  afs: Skip truncation on the server of data we haven't written yet
  afs: Copy local writes to the cache when writing to the server
  afs: Convert afs to use the new fscache API
  fscache, cachefiles: Display stat of culling events
  fscache, cachefiles: Display stats of no-space events
  cachefiles: Allow cachefiles to actually function
  fscache, cachefiles: Store the volume coherency data
  cachefiles: Implement the I/O routines
  cachefiles: Implement cookie resize for truncate
  cachefiles: Implement begin and end I/O operation
  cachefiles: Implement backing file wrangling
  ...
2022-01-12 13:45:12 -08:00

779 lines
18 KiB
C

/* AFS superblock handling
*
* Copyright (c) 2002, 2007, 2018 Red Hat, Inc. All rights reserved.
*
* This software may be freely redistributed under the terms of the
* GNU General Public License.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Authors: David Howells <dhowells@redhat.com>
* David Woodhouse <dwmw2@infradead.org>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/fs_parser.h>
#include <linux/statfs.h>
#include <linux/sched.h>
#include <linux/nsproxy.h>
#include <linux/magic.h>
#include <net/net_namespace.h>
#include "internal.h"
static void afs_i_init_once(void *foo);
static void afs_kill_super(struct super_block *sb);
static struct inode *afs_alloc_inode(struct super_block *sb);
static void afs_destroy_inode(struct inode *inode);
static void afs_free_inode(struct inode *inode);
static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
static int afs_show_devname(struct seq_file *m, struct dentry *root);
static int afs_show_options(struct seq_file *m, struct dentry *root);
static int afs_init_fs_context(struct fs_context *fc);
static const struct fs_parameter_spec afs_fs_parameters[];
struct file_system_type afs_fs_type = {
.owner = THIS_MODULE,
.name = "afs",
.init_fs_context = afs_init_fs_context,
.parameters = afs_fs_parameters,
.kill_sb = afs_kill_super,
.fs_flags = FS_RENAME_DOES_D_MOVE,
};
MODULE_ALIAS_FS("afs");
int afs_net_id;
static const struct super_operations afs_super_ops = {
.statfs = afs_statfs,
.alloc_inode = afs_alloc_inode,
.write_inode = afs_write_inode,
.drop_inode = afs_drop_inode,
.destroy_inode = afs_destroy_inode,
.free_inode = afs_free_inode,
.evict_inode = afs_evict_inode,
.show_devname = afs_show_devname,
.show_options = afs_show_options,
};
static struct kmem_cache *afs_inode_cachep;
static atomic_t afs_count_active_inodes;
enum afs_param {
Opt_autocell,
Opt_dyn,
Opt_flock,
Opt_source,
};
static const struct constant_table afs_param_flock[] = {
{"local", afs_flock_mode_local },
{"openafs", afs_flock_mode_openafs },
{"strict", afs_flock_mode_strict },
{"write", afs_flock_mode_write },
{}
};
static const struct fs_parameter_spec afs_fs_parameters[] = {
fsparam_flag ("autocell", Opt_autocell),
fsparam_flag ("dyn", Opt_dyn),
fsparam_enum ("flock", Opt_flock, afs_param_flock),
fsparam_string("source", Opt_source),
{}
};
/*
* initialise the filesystem
*/
int __init afs_fs_init(void)
{
int ret;
_enter("");
/* create ourselves an inode cache */
atomic_set(&afs_count_active_inodes, 0);
ret = -ENOMEM;
afs_inode_cachep = kmem_cache_create("afs_inode_cache",
sizeof(struct afs_vnode),
0,
SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
afs_i_init_once);
if (!afs_inode_cachep) {
printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
return ret;
}
/* now export our filesystem to lesser mortals */
ret = register_filesystem(&afs_fs_type);
if (ret < 0) {
kmem_cache_destroy(afs_inode_cachep);
_leave(" = %d", ret);
return ret;
}
_leave(" = 0");
return 0;
}
/*
* clean up the filesystem
*/
void afs_fs_exit(void)
{
_enter("");
afs_mntpt_kill_timer();
unregister_filesystem(&afs_fs_type);
if (atomic_read(&afs_count_active_inodes) != 0) {
printk("kAFS: %d active inode objects still present\n",
atomic_read(&afs_count_active_inodes));
BUG();
}
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(afs_inode_cachep);
_leave("");
}
/*
* Display the mount device name in /proc/mounts.
*/
static int afs_show_devname(struct seq_file *m, struct dentry *root)
{
struct afs_super_info *as = AFS_FS_S(root->d_sb);
struct afs_volume *volume = as->volume;
struct afs_cell *cell = as->cell;
const char *suf = "";
char pref = '%';
if (as->dyn_root) {
seq_puts(m, "none");
return 0;
}
switch (volume->type) {
case AFSVL_RWVOL:
break;
case AFSVL_ROVOL:
pref = '#';
if (volume->type_force)
suf = ".readonly";
break;
case AFSVL_BACKVOL:
pref = '#';
suf = ".backup";
break;
}
seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
return 0;
}
/*
* Display the mount options in /proc/mounts.
*/
static int afs_show_options(struct seq_file *m, struct dentry *root)
{
struct afs_super_info *as = AFS_FS_S(root->d_sb);
const char *p = NULL;
if (as->dyn_root)
seq_puts(m, ",dyn");
if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
seq_puts(m, ",autocell");
switch (as->flock_mode) {
case afs_flock_mode_unset: break;
case afs_flock_mode_local: p = "local"; break;
case afs_flock_mode_openafs: p = "openafs"; break;
case afs_flock_mode_strict: p = "strict"; break;
case afs_flock_mode_write: p = "write"; break;
}
if (p)
seq_printf(m, ",flock=%s", p);
return 0;
}
/*
* Parse the source name to get cell name, volume name, volume type and R/W
* selector.
*
* This can be one of the following:
* "%[cell:]volume[.]" R/W volume
* "#[cell:]volume[.]" R/O or R/W volume (R/O parent),
* or R/W (R/W parent) volume
* "%[cell:]volume.readonly" R/O volume
* "#[cell:]volume.readonly" R/O volume
* "%[cell:]volume.backup" Backup volume
* "#[cell:]volume.backup" Backup volume
*/
static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_cell *cell;
const char *cellname, *suffix, *name = param->string;
int cellnamesz;
_enter(",%s", name);
if (fc->source)
return invalf(fc, "kAFS: Multiple sources not supported");
if (!name) {
printk(KERN_ERR "kAFS: no volume name specified\n");
return -EINVAL;
}
if ((name[0] != '%' && name[0] != '#') || !name[1]) {
/* To use dynroot, we don't want to have to provide a source */
if (strcmp(name, "none") == 0) {
ctx->no_cell = true;
return 0;
}
printk(KERN_ERR "kAFS: unparsable volume name\n");
return -EINVAL;
}
/* determine the type of volume we're looking for */
if (name[0] == '%') {
ctx->type = AFSVL_RWVOL;
ctx->force = true;
}
name++;
/* split the cell name out if there is one */
ctx->volname = strchr(name, ':');
if (ctx->volname) {
cellname = name;
cellnamesz = ctx->volname - name;
ctx->volname++;
} else {
ctx->volname = name;
cellname = NULL;
cellnamesz = 0;
}
/* the volume type is further affected by a possible suffix */
suffix = strrchr(ctx->volname, '.');
if (suffix) {
if (strcmp(suffix, ".readonly") == 0) {
ctx->type = AFSVL_ROVOL;
ctx->force = true;
} else if (strcmp(suffix, ".backup") == 0) {
ctx->type = AFSVL_BACKVOL;
ctx->force = true;
} else if (suffix[1] == 0) {
} else {
suffix = NULL;
}
}
ctx->volnamesz = suffix ?
suffix - ctx->volname : strlen(ctx->volname);
_debug("cell %*.*s [%p]",
cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
/* lookup the cell record */
if (cellname) {
cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
NULL, false);
if (IS_ERR(cell)) {
pr_err("kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");
return PTR_ERR(cell);
}
afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_parse);
afs_see_cell(cell, afs_cell_trace_see_source);
ctx->cell = cell;
}
_debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
ctx->cell->name, ctx->cell,
ctx->volnamesz, ctx->volnamesz, ctx->volname,
suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
fc->source = param->string;
param->string = NULL;
return 0;
}
/*
* Parse a single mount parameter.
*/
static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct fs_parse_result result;
struct afs_fs_context *ctx = fc->fs_private;
int opt;
opt = fs_parse(fc, afs_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_source:
return afs_parse_source(fc, param);
case Opt_autocell:
ctx->autocell = true;
break;
case Opt_dyn:
ctx->dyn_root = true;
break;
case Opt_flock:
ctx->flock_mode = result.uint_32;
break;
default:
return -EINVAL;
}
_leave(" = 0");
return 0;
}
/*
* Validate the options, get the cell key and look up the volume.
*/
static int afs_validate_fc(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_volume *volume;
struct afs_cell *cell;
struct key *key;
int ret;
if (!ctx->dyn_root) {
if (ctx->no_cell) {
pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
return -EINVAL;
}
if (!ctx->cell) {
pr_warn("kAFS: No cell specified\n");
return -EDESTADDRREQ;
}
reget_key:
/* We try to do the mount securely. */
key = afs_request_key(ctx->cell);
if (IS_ERR(key))
return PTR_ERR(key);
ctx->key = key;
if (ctx->volume) {
afs_put_volume(ctx->net, ctx->volume,
afs_volume_trace_put_validate_fc);
ctx->volume = NULL;
}
if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &ctx->cell->flags)) {
ret = afs_cell_detect_alias(ctx->cell, key);
if (ret < 0)
return ret;
if (ret == 1) {
_debug("switch to alias");
key_put(ctx->key);
ctx->key = NULL;
cell = afs_use_cell(ctx->cell->alias_of,
afs_cell_trace_use_fc_alias);
afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
ctx->cell = cell;
goto reget_key;
}
}
volume = afs_create_volume(ctx);
if (IS_ERR(volume))
return PTR_ERR(volume);
ctx->volume = volume;
}
return 0;
}
/*
* check a superblock to see if it's the one we're looking for
*/
static int afs_test_super(struct super_block *sb, struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_super_info *as = AFS_FS_S(sb);
return (as->net_ns == fc->net_ns &&
as->volume &&
as->volume->vid == ctx->volume->vid &&
as->cell == ctx->cell &&
!as->dyn_root);
}
static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
{
struct afs_super_info *as = AFS_FS_S(sb);
return (as->net_ns == fc->net_ns &&
as->dyn_root);
}
static int afs_set_super(struct super_block *sb, struct fs_context *fc)
{
return set_anon_super(sb, NULL);
}
/*
* fill in the superblock
*/
static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
{
struct afs_super_info *as = AFS_FS_S(sb);
struct inode *inode = NULL;
int ret;
_enter("");
/* fill in the superblock */
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_magic = AFS_FS_MAGIC;
sb->s_op = &afs_super_ops;
if (!as->dyn_root)
sb->s_xattr = afs_xattr_handlers;
ret = super_setup_bdi(sb);
if (ret)
return ret;
/* allocate the root inode and dentry */
if (as->dyn_root) {
inode = afs_iget_pseudo_dir(sb, true);
} else {
sprintf(sb->s_id, "%llu", as->volume->vid);
afs_activate_volume(as->volume);
inode = afs_root_iget(sb, ctx->key);
}
if (IS_ERR(inode))
return PTR_ERR(inode);
if (ctx->autocell || as->dyn_root)
set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
ret = -ENOMEM;
sb->s_root = d_make_root(inode);
if (!sb->s_root)
goto error;
if (as->dyn_root) {
sb->s_d_op = &afs_dynroot_dentry_operations;
ret = afs_dynroot_populate(sb);
if (ret < 0)
goto error;
} else {
sb->s_d_op = &afs_fs_dentry_operations;
rcu_assign_pointer(as->volume->sb, sb);
}
_leave(" = 0");
return 0;
error:
_leave(" = %d", ret);
return ret;
}
static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_super_info *as;
as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (as) {
as->net_ns = get_net(fc->net_ns);
as->flock_mode = ctx->flock_mode;
if (ctx->dyn_root) {
as->dyn_root = true;
} else {
as->cell = afs_use_cell(ctx->cell, afs_cell_trace_use_sbi);
as->volume = afs_get_volume(ctx->volume,
afs_volume_trace_get_alloc_sbi);
}
}
return as;
}
static void afs_destroy_sbi(struct afs_super_info *as)
{
if (as) {
struct afs_net *net = afs_net(as->net_ns);
afs_put_volume(net, as->volume, afs_volume_trace_put_destroy_sbi);
afs_unuse_cell(net, as->cell, afs_cell_trace_unuse_sbi);
put_net(as->net_ns);
kfree(as);
}
}
static void afs_kill_super(struct super_block *sb)
{
struct afs_super_info *as = AFS_FS_S(sb);
if (as->dyn_root)
afs_dynroot_depopulate(sb);
/* Clear the callback interests (which will do ilookup5) before
* deactivating the superblock.
*/
if (as->volume)
rcu_assign_pointer(as->volume->sb, NULL);
kill_anon_super(sb);
if (as->volume)
afs_deactivate_volume(as->volume);
afs_destroy_sbi(as);
}
/*
* Get an AFS superblock and root directory.
*/
static int afs_get_tree(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
struct super_block *sb;
struct afs_super_info *as;
int ret;
ret = afs_validate_fc(fc);
if (ret)
goto error;
_enter("");
/* allocate a superblock info record */
ret = -ENOMEM;
as = afs_alloc_sbi(fc);
if (!as)
goto error;
fc->s_fs_info = as;
/* allocate a deviceless superblock */
sb = sget_fc(fc,
as->dyn_root ? afs_dynroot_test_super : afs_test_super,
afs_set_super);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
goto error;
}
if (!sb->s_root) {
/* initial superblock/root creation */
_debug("create");
ret = afs_fill_super(sb, ctx);
if (ret < 0)
goto error_sb;
sb->s_flags |= SB_ACTIVE;
} else {
_debug("reuse");
ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
}
fc->root = dget(sb->s_root);
trace_afs_get_tree(as->cell, as->volume);
_leave(" = 0 [%p]", sb);
return 0;
error_sb:
deactivate_locked_super(sb);
error:
_leave(" = %d", ret);
return ret;
}
static void afs_free_fc(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
afs_destroy_sbi(fc->s_fs_info);
afs_put_volume(ctx->net, ctx->volume, afs_volume_trace_put_free_fc);
afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
key_put(ctx->key);
kfree(ctx);
}
static const struct fs_context_operations afs_context_ops = {
.free = afs_free_fc,
.parse_param = afs_parse_param,
.get_tree = afs_get_tree,
};
/*
* Set up the filesystem mount context.
*/
static int afs_init_fs_context(struct fs_context *fc)
{
struct afs_fs_context *ctx;
struct afs_cell *cell;
ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->type = AFSVL_ROVOL;
ctx->net = afs_net(fc->net_ns);
/* Default to the workstation cell. */
cell = afs_find_cell(ctx->net, NULL, 0, afs_cell_trace_use_fc);
if (IS_ERR(cell))
cell = NULL;
ctx->cell = cell;
fc->fs_private = ctx;
fc->ops = &afs_context_ops;
return 0;
}
/*
* Initialise an inode cache slab element prior to any use. Note that
* afs_alloc_inode() *must* reset anything that could incorrectly leak from one
* inode to another.
*/
static void afs_i_init_once(void *_vnode)
{
struct afs_vnode *vnode = _vnode;
memset(vnode, 0, sizeof(*vnode));
inode_init_once(&vnode->vfs_inode);
mutex_init(&vnode->io_lock);
init_rwsem(&vnode->validate_lock);
spin_lock_init(&vnode->wb_lock);
spin_lock_init(&vnode->lock);
INIT_LIST_HEAD(&vnode->wb_keys);
INIT_LIST_HEAD(&vnode->pending_locks);
INIT_LIST_HEAD(&vnode->granted_locks);
INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
INIT_LIST_HEAD(&vnode->cb_mmap_link);
seqlock_init(&vnode->cb_lock);
}
/*
* allocate an AFS inode struct from our slab cache
*/
static struct inode *afs_alloc_inode(struct super_block *sb)
{
struct afs_vnode *vnode;
vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
if (!vnode)
return NULL;
atomic_inc(&afs_count_active_inodes);
/* Reset anything that shouldn't leak from one inode to the next. */
memset(&vnode->fid, 0, sizeof(vnode->fid));
memset(&vnode->status, 0, sizeof(vnode->status));
vnode->volume = NULL;
vnode->lock_key = NULL;
vnode->permit_cache = NULL;
#ifdef CONFIG_AFS_FSCACHE
vnode->cache = NULL;
#endif
vnode->flags = 1 << AFS_VNODE_UNSET;
vnode->lock_state = AFS_VNODE_LOCK_NONE;
init_rwsem(&vnode->rmdir_lock);
INIT_WORK(&vnode->cb_work, afs_invalidate_mmap_work);
_leave(" = %p", &vnode->vfs_inode);
return &vnode->vfs_inode;
}
static void afs_free_inode(struct inode *inode)
{
kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
}
/*
* destroy an AFS inode struct
*/
static void afs_destroy_inode(struct inode *inode)
{
struct afs_vnode *vnode = AFS_FS_I(inode);
_enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
_debug("DESTROY INODE %p", inode);
atomic_dec(&afs_count_active_inodes);
}
static void afs_get_volume_status_success(struct afs_operation *op)
{
struct afs_volume_status *vs = &op->volstatus.vs;
struct kstatfs *buf = op->volstatus.buf;
if (vs->max_quota == 0)
buf->f_blocks = vs->part_max_blocks;
else
buf->f_blocks = vs->max_quota;
if (buf->f_blocks > vs->blocks_in_use)
buf->f_bavail = buf->f_bfree =
buf->f_blocks - vs->blocks_in_use;
}
static const struct afs_operation_ops afs_get_volume_status_operation = {
.issue_afs_rpc = afs_fs_get_volume_status,
.issue_yfs_rpc = yfs_fs_get_volume_status,
.success = afs_get_volume_status_success,
};
/*
* return information about an AFS volume
*/
static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
struct afs_operation *op;
struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
buf->f_type = dentry->d_sb->s_magic;
buf->f_bsize = AFS_BLOCK_SIZE;
buf->f_namelen = AFSNAMEMAX - 1;
if (as->dyn_root) {
buf->f_blocks = 1;
buf->f_bavail = 0;
buf->f_bfree = 0;
return 0;
}
op = afs_alloc_operation(NULL, as->volume);
if (IS_ERR(op))
return PTR_ERR(op);
afs_op_set_vnode(op, 0, vnode);
op->nr_files = 1;
op->volstatus.buf = buf;
op->ops = &afs_get_volume_status_operation;
return afs_do_sync_operation(op);
}