Revision b91e1302ad9b80c174a4855533f7e3aa2873355e authored by Linus Torvalds on 27 December 2016, 19:40:38 UTC, committed by Linus Torvalds on 29 December 2016, 19:03:15 UTC
In commit 62906027091f ("mm: add PageWaiters indicating tasks are
waiting for a page bit") Nick Piggin made our page locking no longer
unconditionally touch the hashed page waitqueue, which not only helps
performance in general, but is particularly helpful on NUMA machines
where the hashed wait queues can bounce around a lot.
However, the "clear lock bit atomically and then test the waiters bit"
sequence turns out to be much more expensive than it needs to be,
because you get a nasty stall when trying to access the same word that
just got updated atomically.
On architectures where locking is done with LL/SC, this would be trivial
to fix with a new primitive that clears one bit and tests another
atomically, but that ends up not working on x86, where the only atomic
operations that return the result end up being cmpxchg and xadd. The
atomic bit operations return the old value of the same bit we changed,
not the value of an unrelated bit.
On x86, we could put the lock bit in the high bit of the byte, and use
"xadd" with that bit (where the overflow ends up not touching other
bits), and look at the other bits of the result. However, an even
simpler model is to just use a regular atomic "and" to clear the lock
bit, and then the sign bit in eflags will indicate the resulting state
of the unrelated bit #7.
So by moving the PageWaiters bit up to bit #7, we can atomically clear
the lock bit and test the waiters bit on x86 too. And architectures
with LL/SC (which is all the usual RISC suspects), the particular bit
doesn't matter, so they are fine with this approach too.
This avoids the extra access to the same atomic word, and thus avoids
the costly stall at page unlock time.
The only downside is that the interface ends up being a bit odd and
specialized: clear a bit in a byte, and test the sign bit. Nick doesn't
love the resulting name of the new primitive, but I'd rather make the
name be descriptive and very clear about the limitation imposed by
trying to work across all relevant architectures than make it be some
generic thing that doesn't make the odd semantics explicit.
So this introduces the new architecture primitive
clear_bit_unlock_is_negative_byte();
and adds the trivial implementation for x86. We have a generic
non-optimized fallback (that just does a "clear_bit()"+"test_bit(7)"
combination) which can be overridden by any architecture that can do
better. According to Nick, Power has the same hickup x86 has, for
example, but some other architectures may not even care.
All these optimizations mean that my page locking stress-test (which is
just executing a lot of small short-lived shell scripts: "make test" in
the git source tree) no longer makes our page locking look horribly bad.
Before all these optimizations, just the unlock_page() costs were just
over 3% of all CPU overhead on "make test". After this, it's down to
0.66%, so just a quarter of the cost it used to be.
(The difference on NUMA is bigger, but there this micro-optimization is
likely less noticeable, since the big issue on NUMA was not the accesses
to 'struct page', but the waitqueue accesses that were already removed
by Nick's earlier commit).
Acked-by: Nick Piggin <npiggin@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 2d706e7
dir.c
/* dir.c: AFS filesystem directory handling
*
* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include "internal.h"
static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);
static int afs_dir_open(struct inode *inode, struct file *file);
static int afs_readdir(struct file *file, struct dir_context *ctx);
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
static int afs_d_delete(const struct dentry *dentry);
static void afs_d_release(struct dentry *dentry);
static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
loff_t fpos, u64 ino, unsigned dtype);
static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool excl);
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
static int afs_rmdir(struct inode *dir, struct dentry *dentry);
static int afs_unlink(struct inode *dir, struct dentry *dentry);
static int afs_link(struct dentry *from, struct inode *dir,
struct dentry *dentry);
static int afs_symlink(struct inode *dir, struct dentry *dentry,
const char *content);
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags);
const struct file_operations afs_dir_file_operations = {
.open = afs_dir_open,
.release = afs_release,
.iterate_shared = afs_readdir,
.lock = afs_lock,
.llseek = generic_file_llseek,
};
const struct inode_operations afs_dir_inode_operations = {
.create = afs_create,
.lookup = afs_lookup,
.link = afs_link,
.unlink = afs_unlink,
.symlink = afs_symlink,
.mkdir = afs_mkdir,
.rmdir = afs_rmdir,
.rename = afs_rename,
.permission = afs_permission,
.getattr = afs_getattr,
.setattr = afs_setattr,
};
const struct dentry_operations afs_fs_dentry_operations = {
.d_revalidate = afs_d_revalidate,
.d_delete = afs_d_delete,
.d_release = afs_d_release,
.d_automount = afs_d_automount,
};
#define AFS_DIR_HASHTBL_SIZE 128
#define AFS_DIR_DIRENT_SIZE 32
#define AFS_DIRENT_PER_BLOCK 64
union afs_dirent {
struct {
uint8_t valid;
uint8_t unused[1];
__be16 hash_next;
__be32 vnode;
__be32 unique;
uint8_t name[16];
uint8_t overflow[4]; /* if any char of the name (inc
* NUL) reaches here, consume
* the next dirent too */
} u;
uint8_t extended_name[32];
};
/* AFS directory page header (one at the beginning of every 2048-byte chunk) */
struct afs_dir_pagehdr {
__be16 npages;
__be16 magic;
#define AFS_DIR_MAGIC htons(1234)
uint8_t nentries;
uint8_t bitmap[8];
uint8_t pad[19];
};
/* directory block layout */
union afs_dir_block {
struct afs_dir_pagehdr pagehdr;
struct {
struct afs_dir_pagehdr pagehdr;
uint8_t alloc_ctrs[128];
/* dir hash table */
uint16_t hashtable[AFS_DIR_HASHTBL_SIZE];
} hdr;
union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
};
/* layout on a linux VM page */
struct afs_dir_page {
union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
};
struct afs_lookup_cookie {
struct dir_context ctx;
struct afs_fid fid;
struct qstr name;
int found;
};
/*
* check that a directory page is valid
*/
static inline bool afs_dir_check_page(struct inode *dir, struct page *page)
{
struct afs_dir_page *dbuf;
loff_t latter;
int tmp, qty;
#if 0
/* check the page count */
qty = desc.size / sizeof(dbuf->blocks[0]);
if (qty == 0)
goto error;
if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
__func__, dir->i_ino, qty,
ntohs(dbuf->blocks[0].pagehdr.npages));
goto error;
}
#endif
/* determine how many magic numbers there should be in this page */
latter = dir->i_size - page_offset(page);
if (latter >= PAGE_SIZE)
qty = PAGE_SIZE;
else
qty = latter;
qty /= sizeof(union afs_dir_block);
/* check them */
dbuf = page_address(page);
for (tmp = 0; tmp < qty; tmp++) {
if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
__func__, dir->i_ino, tmp, qty,
ntohs(dbuf->blocks[tmp].pagehdr.magic));
goto error;
}
}
SetPageChecked(page);
return true;
error:
SetPageError(page);
return false;
}
/*
* discard a page cached in the pagecache
*/
static inline void afs_dir_put_page(struct page *page)
{
kunmap(page);
put_page(page);
}
/*
* get a page into the pagecache
*/
static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
struct key *key)
{
struct page *page;
_enter("{%lu},%lu", dir->i_ino, index);
page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
if (!IS_ERR(page)) {
kmap(page);
if (unlikely(!PageChecked(page))) {
if (PageError(page) || !afs_dir_check_page(dir, page))
goto fail;
}
}
return page;
fail:
afs_dir_put_page(page);
_leave(" = -EIO");
return ERR_PTR(-EIO);
}
/*
* open an AFS directory file
*/
static int afs_dir_open(struct inode *inode, struct file *file)
{
_enter("{%lu}", inode->i_ino);
BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
return -ENOENT;
return afs_open(inode, file);
}
/*
* deal with one block in an AFS directory
*/
static int afs_dir_iterate_block(struct dir_context *ctx,
union afs_dir_block *block,
unsigned blkoff)
{
union afs_dirent *dire;
unsigned offset, next, curr;
size_t nlen;
int tmp;
_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
curr = (ctx->pos - blkoff) / sizeof(union afs_dirent);
/* walk through the block, an entry at a time */
for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
offset < AFS_DIRENT_PER_BLOCK;
offset = next
) {
next = offset + 1;
/* skip entries marked unused in the bitmap */
if (!(block->pagehdr.bitmap[offset / 8] &
(1 << (offset % 8)))) {
_debug("ENT[%Zu.%u]: unused",
blkoff / sizeof(union afs_dir_block), offset);
if (offset >= curr)
ctx->pos = blkoff +
next * sizeof(union afs_dirent);
continue;
}
/* got a valid entry */
dire = &block->dirents[offset];
nlen = strnlen(dire->u.name,
sizeof(*block) -
offset * sizeof(union afs_dirent));
_debug("ENT[%Zu.%u]: %s %Zu \"%s\"",
blkoff / sizeof(union afs_dir_block), offset,
(offset < curr ? "skip" : "fill"),
nlen, dire->u.name);
/* work out where the next possible entry is */
for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {
if (next >= AFS_DIRENT_PER_BLOCK) {
_debug("ENT[%Zu.%u]:"
" %u travelled beyond end dir block"
" (len %u/%Zu)",
blkoff / sizeof(union afs_dir_block),
offset, next, tmp, nlen);
return -EIO;
}
if (!(block->pagehdr.bitmap[next / 8] &
(1 << (next % 8)))) {
_debug("ENT[%Zu.%u]:"
" %u unmarked extension (len %u/%Zu)",
blkoff / sizeof(union afs_dir_block),
offset, next, tmp, nlen);
return -EIO;
}
_debug("ENT[%Zu.%u]: ext %u/%Zu",
blkoff / sizeof(union afs_dir_block),
next, tmp, nlen);
next++;
}
/* skip if starts before the current position */
if (offset < curr)
continue;
/* found the next entry */
if (!dir_emit(ctx, dire->u.name, nlen,
ntohl(dire->u.vnode),
ctx->actor == afs_lookup_filldir ?
ntohl(dire->u.unique) : DT_UNKNOWN)) {
_leave(" = 0 [full]");
return 0;
}
ctx->pos = blkoff + next * sizeof(union afs_dirent);
}
_leave(" = 1 [more]");
return 1;
}
/*
* iterate through the data blob that lists the contents of an AFS directory
*/
static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
struct key *key)
{
union afs_dir_block *dblock;
struct afs_dir_page *dbuf;
struct page *page;
unsigned blkoff, limit;
int ret;
_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
_leave(" = -ESTALE");
return -ESTALE;
}
/* round the file position up to the next entry boundary */
ctx->pos += sizeof(union afs_dirent) - 1;
ctx->pos &= ~(sizeof(union afs_dirent) - 1);
/* walk through the blocks in sequence */
ret = 0;
while (ctx->pos < dir->i_size) {
blkoff = ctx->pos & ~(sizeof(union afs_dir_block) - 1);
/* fetch the appropriate page from the directory */
page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
if (IS_ERR(page)) {
ret = PTR_ERR(page);
break;
}
limit = blkoff & ~(PAGE_SIZE - 1);
dbuf = page_address(page);
/* deal with the individual blocks stashed on this page */
do {
dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
sizeof(union afs_dir_block)];
ret = afs_dir_iterate_block(ctx, dblock, blkoff);
if (ret != 1) {
afs_dir_put_page(page);
goto out;
}
blkoff += sizeof(union afs_dir_block);
} while (ctx->pos < dir->i_size && blkoff < limit);
afs_dir_put_page(page);
ret = 0;
}
out:
_leave(" = %d", ret);
return ret;
}
/*
* read an AFS directory
*/
static int afs_readdir(struct file *file, struct dir_context *ctx)
{
return afs_dir_iterate(file_inode(file),
ctx, file->private_data);
}
/*
* search the directory for a name
* - if afs_dir_iterate_block() spots this function, it'll pass the FID
* uniquifier through dtype
*/
static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
struct afs_lookup_cookie *cookie =
container_of(ctx, struct afs_lookup_cookie, ctx);
_enter("{%s,%u},%s,%u,,%llu,%u",
cookie->name.name, cookie->name.len, name, nlen,
(unsigned long long) ino, dtype);
/* insanity checks first */
BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
if (cookie->name.len != nlen ||
memcmp(cookie->name.name, name, nlen) != 0) {
_leave(" = 0 [no]");
return 0;
}
cookie->fid.vnode = ino;
cookie->fid.unique = dtype;
cookie->found = 1;
_leave(" = -1 [found]");
return -1;
}
/*
* do a lookup in a directory
* - just returns the FID the dentry name maps to if found
*/
static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
struct afs_fid *fid, struct key *key)
{
struct afs_super_info *as = dir->i_sb->s_fs_info;
struct afs_lookup_cookie cookie = {
.ctx.actor = afs_lookup_filldir,
.name = dentry->d_name,
.fid.vid = as->volume->vid
};
int ret;
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
/* search the directory */
ret = afs_dir_iterate(dir, &cookie.ctx, key);
if (ret < 0) {
_leave(" = %d [iter]", ret);
return ret;
}
ret = -ENOENT;
if (!cookie.found) {
_leave(" = -ENOENT [not found]");
return -ENOENT;
}
*fid = cookie.fid;
_leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);
return 0;
}
/*
* Try to auto mount the mountpoint with pseudo directory, if the autocell
* operation is setted.
*/
static struct inode *afs_try_auto_mntpt(
int ret, struct dentry *dentry, struct inode *dir, struct key *key,
struct afs_fid *fid)
{
const char *devname = dentry->d_name.name;
struct afs_vnode *vnode = AFS_FS_I(dir);
struct inode *inode;
_enter("%d, %p{%pd}, {%x:%u}, %p",
ret, dentry, dentry, vnode->fid.vid, vnode->fid.vnode, key);
if (ret != -ENOENT ||
!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
goto out;
inode = afs_iget_autocell(dir, devname, strlen(devname), key);
if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
goto out;
}
*fid = AFS_FS_I(inode)->fid;
_leave("= %p", inode);
return inode;
out:
_leave("= %d", ret);
return ERR_PTR(ret);
}
/*
* look up an entry in a directory
*/
static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct afs_vnode *vnode;
struct afs_fid fid;
struct inode *inode;
struct key *key;
int ret;
vnode = AFS_FS_I(dir);
_enter("{%x:%u},%p{%pd},",
vnode->fid.vid, vnode->fid.vnode, dentry, dentry);
ASSERTCMP(d_inode(dentry), ==, NULL);
if (dentry->d_name.len >= AFSNAMEMAX) {
_leave(" = -ENAMETOOLONG");
return ERR_PTR(-ENAMETOOLONG);
}
if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
_leave(" = -ESTALE");
return ERR_PTR(-ESTALE);
}
key = afs_request_key(vnode->volume->cell);
if (IS_ERR(key)) {
_leave(" = %ld [key]", PTR_ERR(key));
return ERR_CAST(key);
}
ret = afs_validate(vnode, key);
if (ret < 0) {
key_put(key);
_leave(" = %d [val]", ret);
return ERR_PTR(ret);
}
ret = afs_do_lookup(dir, dentry, &fid, key);
if (ret < 0) {
inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
if (!IS_ERR(inode)) {
key_put(key);
goto success;
}
ret = PTR_ERR(inode);
key_put(key);
if (ret == -ENOENT) {
d_add(dentry, NULL);
_leave(" = NULL [negative]");
return NULL;
}
_leave(" = %d [do]", ret);
return ERR_PTR(ret);
}
dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
/* instantiate the dentry */
inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);
key_put(key);
if (IS_ERR(inode)) {
_leave(" = %ld", PTR_ERR(inode));
return ERR_CAST(inode);
}
success:
d_add(dentry, inode);
_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
fid.vnode,
fid.unique,
d_inode(dentry)->i_ino,
d_inode(dentry)->i_generation);
return NULL;
}
/*
* check that a dentry lookup hit has found a valid entry
* - NOTE! the hit can be a negative hit too, so we can't assume we have an
* inode
*/
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
{
struct afs_vnode *vnode, *dir;
struct afs_fid uninitialized_var(fid);
struct dentry *parent;
struct key *key;
void *dir_version;
int ret;
if (flags & LOOKUP_RCU)
return -ECHILD;
vnode = AFS_FS_I(d_inode(dentry));
if (d_really_is_positive(dentry))
_enter("{v={%x:%u} n=%pd fl=%lx},",
vnode->fid.vid, vnode->fid.vnode, dentry,
vnode->flags);
else
_enter("{neg n=%pd}", dentry);
key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
if (IS_ERR(key))
key = NULL;
/* lock down the parent dentry so we can peer at it */
parent = dget_parent(dentry);
dir = AFS_FS_I(d_inode(parent));
/* validate the parent directory */
if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
afs_validate(dir, key);
if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
_debug("%pd: parent dir deleted", dentry);
goto out_bad;
}
dir_version = (void *) (unsigned long) dir->status.data_version;
if (dentry->d_fsdata == dir_version)
goto out_valid; /* the dir contents are unchanged */
_debug("dir modified");
/* search the directory for this vnode */
ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
switch (ret) {
case 0:
/* the filename maps to something */
if (d_really_is_negative(dentry))
goto out_bad;
if (is_bad_inode(d_inode(dentry))) {
printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n",
dentry);
goto out_bad;
}
/* if the vnode ID has changed, then the dirent points to a
* different file */
if (fid.vnode != vnode->fid.vnode) {
_debug("%pd: dirent changed [%u != %u]",
dentry, fid.vnode,
vnode->fid.vnode);
goto not_found;
}
/* if the vnode ID uniqifier has changed, then the file has
* been deleted and replaced, and the original vnode ID has
* been reused */
if (fid.unique != vnode->fid.unique) {
_debug("%pd: file deleted (uq %u -> %u I:%u)",
dentry, fid.unique,
vnode->fid.unique,
d_inode(dentry)->i_generation);
spin_lock(&vnode->lock);
set_bit(AFS_VNODE_DELETED, &vnode->flags);
spin_unlock(&vnode->lock);
goto not_found;
}
goto out_valid;
case -ENOENT:
/* the filename is unknown */
_debug("%pd: dirent not found", dentry);
if (d_really_is_positive(dentry))
goto not_found;
goto out_valid;
default:
_debug("failed to iterate dir %pd: %d",
parent, ret);
goto out_bad;
}
out_valid:
dentry->d_fsdata = dir_version;
dput(parent);
key_put(key);
_leave(" = 1 [valid]");
return 1;
/* the dirent, if it exists, now points to a different vnode */
not_found:
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_NFSFS_RENAMED;
spin_unlock(&dentry->d_lock);
out_bad:
_debug("dropping dentry %pd2", dentry);
dput(parent);
key_put(key);
_leave(" = 0 [bad]");
return 0;
}
/*
* allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
* sleep)
* - called from dput() when d_count is going to 0.
* - return 1 to request dentry be unhashed, 0 otherwise
*/
static int afs_d_delete(const struct dentry *dentry)
{
_enter("%pd", dentry);
if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
goto zap;
if (d_really_is_positive(dentry) &&
(test_bit(AFS_VNODE_DELETED, &AFS_FS_I(d_inode(dentry))->flags) ||
test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(d_inode(dentry))->flags)))
goto zap;
_leave(" = 0 [keep]");
return 0;
zap:
_leave(" = 1 [zap]");
return 1;
}
/*
* handle dentry release
*/
static void afs_d_release(struct dentry *dentry)
{
_enter("%pd", dentry);
}
/*
* create a directory on an AFS filesystem
*/
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
struct afs_file_status status;
struct afs_callback cb;
struct afs_server *server;
struct afs_vnode *dvnode, *vnode;
struct afs_fid fid;
struct inode *inode;
struct key *key;
int ret;
dvnode = AFS_FS_I(dir);
_enter("{%x:%u},{%pd},%ho",
dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
mode |= S_IFDIR;
ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
mode, &fid, &status, &cb, &server);
if (ret < 0)
goto mkdir_error;
inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
if (IS_ERR(inode)) {
/* ENOMEM at a really inconvenient time - just abandon the new
* directory on the server */
ret = PTR_ERR(inode);
goto iget_error;
}
/* apply the status report we've got for the new vnode */
vnode = AFS_FS_I(inode);
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_vnode_finalise_status_update(vnode, server);
afs_put_server(server);
d_instantiate(dentry, inode);
if (d_unhashed(dentry)) {
_debug("not hashed");
d_rehash(dentry);
}
key_put(key);
_leave(" = 0");
return 0;
iget_error:
afs_put_server(server);
mkdir_error:
key_put(key);
error:
d_drop(dentry);
_leave(" = %d", ret);
return ret;
}
/*
* remove a directory from an AFS filesystem
*/
static int afs_rmdir(struct inode *dir, struct dentry *dentry)
{
struct afs_vnode *dvnode, *vnode;
struct key *key;
int ret;
dvnode = AFS_FS_I(dir);
_enter("{%x:%u},{%pd}",
dvnode->fid.vid, dvnode->fid.vnode, dentry);
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
if (ret < 0)
goto rmdir_error;
if (d_really_is_positive(dentry)) {
vnode = AFS_FS_I(d_inode(dentry));
clear_nlink(&vnode->vfs_inode);
set_bit(AFS_VNODE_DELETED, &vnode->flags);
afs_discard_callback_on_delete(vnode);
}
key_put(key);
_leave(" = 0");
return 0;
rmdir_error:
key_put(key);
error:
_leave(" = %d", ret);
return ret;
}
/*
* remove a file from an AFS filesystem
*/
static int afs_unlink(struct inode *dir, struct dentry *dentry)
{
struct afs_vnode *dvnode, *vnode;
struct key *key;
int ret;
dvnode = AFS_FS_I(dir);
_enter("{%x:%u},{%pd}",
dvnode->fid.vid, dvnode->fid.vnode, dentry);
ret = -ENAMETOOLONG;
if (dentry->d_name.len >= AFSNAMEMAX)
goto error;
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
if (d_really_is_positive(dentry)) {
vnode = AFS_FS_I(d_inode(dentry));
/* make sure we have a callback promise on the victim */
ret = afs_validate(vnode, key);
if (ret < 0)
goto error;
}
ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
if (ret < 0)
goto remove_error;
if (d_really_is_positive(dentry)) {
/* if the file wasn't deleted due to excess hard links, the
* fileserver will break the callback promise on the file - if
* it had one - before it returns to us, and if it was deleted,
* it won't
*
* however, if we didn't have a callback promise outstanding,
* or it was outstanding on a different server, then it won't
* break it either...
*/
vnode = AFS_FS_I(d_inode(dentry));
if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
_debug("AFS_VNODE_DELETED");
if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
_debug("AFS_VNODE_CB_BROKEN");
set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
ret = afs_validate(vnode, key);
_debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
}
key_put(key);
_leave(" = 0");
return 0;
remove_error:
key_put(key);
error:
_leave(" = %d", ret);
return ret;
}
/*
* create a regular file on an AFS filesystem
*/
static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
bool excl)
{
struct afs_file_status status;
struct afs_callback cb;
struct afs_server *server;
struct afs_vnode *dvnode, *vnode;
struct afs_fid fid;
struct inode *inode;
struct key *key;
int ret;
dvnode = AFS_FS_I(dir);
_enter("{%x:%u},{%pd},%ho,",
dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
mode |= S_IFREG;
ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
mode, &fid, &status, &cb, &server);
if (ret < 0)
goto create_error;
inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
if (IS_ERR(inode)) {
/* ENOMEM at a really inconvenient time - just abandon the new
* directory on the server */
ret = PTR_ERR(inode);
goto iget_error;
}
/* apply the status report we've got for the new vnode */
vnode = AFS_FS_I(inode);
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_vnode_finalise_status_update(vnode, server);
afs_put_server(server);
d_instantiate(dentry, inode);
if (d_unhashed(dentry)) {
_debug("not hashed");
d_rehash(dentry);
}
key_put(key);
_leave(" = 0");
return 0;
iget_error:
afs_put_server(server);
create_error:
key_put(key);
error:
d_drop(dentry);
_leave(" = %d", ret);
return ret;
}
/*
* create a hard link between files in an AFS filesystem
*/
static int afs_link(struct dentry *from, struct inode *dir,
struct dentry *dentry)
{
struct afs_vnode *dvnode, *vnode;
struct key *key;
int ret;
vnode = AFS_FS_I(d_inode(from));
dvnode = AFS_FS_I(dir);
_enter("{%x:%u},{%x:%u},{%pd}",
vnode->fid.vid, vnode->fid.vnode,
dvnode->fid.vid, dvnode->fid.vnode,
dentry);
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
ret = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
if (ret < 0)
goto link_error;
ihold(&vnode->vfs_inode);
d_instantiate(dentry, &vnode->vfs_inode);
key_put(key);
_leave(" = 0");
return 0;
link_error:
key_put(key);
error:
d_drop(dentry);
_leave(" = %d", ret);
return ret;
}
/*
* create a symlink in an AFS filesystem
*/
static int afs_symlink(struct inode *dir, struct dentry *dentry,
const char *content)
{
struct afs_file_status status;
struct afs_server *server;
struct afs_vnode *dvnode, *vnode;
struct afs_fid fid;
struct inode *inode;
struct key *key;
int ret;
dvnode = AFS_FS_I(dir);
_enter("{%x:%u},{%pd},%s",
dvnode->fid.vid, dvnode->fid.vnode, dentry,
content);
ret = -EINVAL;
if (strlen(content) >= AFSPATHMAX)
goto error;
key = afs_request_key(dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
ret = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
&fid, &status, &server);
if (ret < 0)
goto create_error;
inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
if (IS_ERR(inode)) {
/* ENOMEM at a really inconvenient time - just abandon the new
* directory on the server */
ret = PTR_ERR(inode);
goto iget_error;
}
/* apply the status report we've got for the new vnode */
vnode = AFS_FS_I(inode);
spin_lock(&vnode->lock);
vnode->update_cnt++;
spin_unlock(&vnode->lock);
afs_vnode_finalise_status_update(vnode, server);
afs_put_server(server);
d_instantiate(dentry, inode);
if (d_unhashed(dentry)) {
_debug("not hashed");
d_rehash(dentry);
}
key_put(key);
_leave(" = 0");
return 0;
iget_error:
afs_put_server(server);
create_error:
key_put(key);
error:
d_drop(dentry);
_leave(" = %d", ret);
return ret;
}
/*
* rename a file in an AFS filesystem and/or move it between directories
*/
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
struct key *key;
int ret;
if (flags)
return -EINVAL;
vnode = AFS_FS_I(d_inode(old_dentry));
orig_dvnode = AFS_FS_I(old_dir);
new_dvnode = AFS_FS_I(new_dir);
_enter("{%x:%u},{%x:%u},{%x:%u},{%pd}",
orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
vnode->fid.vid, vnode->fid.vnode,
new_dvnode->fid.vid, new_dvnode->fid.vnode,
new_dentry);
key = afs_request_key(orig_dvnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
old_dentry->d_name.name,
new_dentry->d_name.name);
if (ret < 0)
goto rename_error;
key_put(key);
_leave(" = 0");
return 0;
rename_error:
key_put(key);
error:
d_drop(new_dentry);
_leave(" = %d", ret);
return ret;
}
Computing file changes ...
