WSL2-Linux-Kernel/fs/ocfs2/dcache.c

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C
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* dcache.c
*
* dentry cache handling code
*
* Copyright (C) 2002, 2004 Oracle. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "alloc.h"
#include "dcache.h"
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
#include "ocfs2_trace.h"
void ocfs2_dentry_attach_gen(struct dentry *dentry)
{
unsigned long gen =
OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen;
BUG_ON(d_inode(dentry));
dentry->d_fsdata = (void *)gen;
}
static int ocfs2_dentry_revalidate(struct dentry *dentry, unsigned int flags)
{
struct inode *inode;
int ret = 0; /* if all else fails, just return false */
struct ocfs2_super *osb;
if (flags & LOOKUP_RCU)
return -ECHILD;
inode = d_inode(dentry);
osb = OCFS2_SB(dentry->d_sb);
trace_ocfs2_dentry_revalidate(dentry, dentry->d_name.len,
dentry->d_name.name);
/* For a negative dentry -
* check the generation number of the parent and compare with the
* one stored in the inode.
*/
if (inode == NULL) {
unsigned long gen = (unsigned long) dentry->d_fsdata;
unsigned long pgen;
spin_lock(&dentry->d_lock);
pgen = OCFS2_I(d_inode(dentry->d_parent))->ip_dir_lock_gen;
spin_unlock(&dentry->d_lock);
trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len,
dentry->d_name.name,
pgen, gen);
if (gen != pgen)
goto bail;
goto valid;
}
BUG_ON(!osb);
if (inode == osb->root_inode || is_bad_inode(inode))
goto bail;
spin_lock(&OCFS2_I(inode)->ip_lock);
/* did we or someone else delete this inode? */
if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
spin_unlock(&OCFS2_I(inode)->ip_lock);
trace_ocfs2_dentry_revalidate_delete(
(unsigned long long)OCFS2_I(inode)->ip_blkno);
goto bail;
}
spin_unlock(&OCFS2_I(inode)->ip_lock);
/*
* We don't need a cluster lock to test this because once an
* inode nlink hits zero, it never goes back.
*/
if (inode->i_nlink == 0) {
trace_ocfs2_dentry_revalidate_orphaned(
(unsigned long long)OCFS2_I(inode)->ip_blkno,
S_ISDIR(inode->i_mode));
goto bail;
}
/*
* If the last lookup failed to create dentry lock, let us
* redo it.
*/
if (!dentry->d_fsdata) {
trace_ocfs2_dentry_revalidate_nofsdata(
(unsigned long long)OCFS2_I(inode)->ip_blkno);
goto bail;
}
valid:
ret = 1;
bail:
trace_ocfs2_dentry_revalidate_ret(ret);
return ret;
}
static int ocfs2_match_dentry(struct dentry *dentry,
u64 parent_blkno,
int skip_unhashed)
{
struct inode *parent;
/*
* ocfs2_lookup() does a d_splice_alias() _before_ attaching
* to the lock data, so we skip those here, otherwise
* ocfs2_dentry_attach_lock() will get its original dentry
* back.
*/
if (!dentry->d_fsdata)
return 0;
if (!dentry->d_parent)
return 0;
if (skip_unhashed && d_unhashed(dentry))
return 0;
parent = d_inode(dentry->d_parent);
/* Negative parent dentry? */
if (!parent)
return 0;
/* Name is in a different directory. */
if (OCFS2_I(parent)->ip_blkno != parent_blkno)
return 0;
return 1;
}
/*
* Walk the inode alias list, and find a dentry which has a given
* parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it
* is looking for a dentry_lock reference. The downconvert thread is
* looking to unhash aliases, so we allow it to skip any that already
* have that property.
*/
struct dentry *ocfs2_find_local_alias(struct inode *inode,
u64 parent_blkno,
int skip_unhashed)
{
struct dentry *dentry;
spin_lock(&inode->i_lock);
hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
spin_lock(&dentry->d_lock);
if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) {
trace_ocfs2_find_local_alias(dentry->d_name.len,
dentry->d_name.name);
dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
return dentry;
}
spin_unlock(&dentry->d_lock);
}
spin_unlock(&inode->i_lock);
return NULL;
}
DEFINE_SPINLOCK(dentry_attach_lock);
/*
* Attach this dentry to a cluster lock.
*
* Dentry locks cover all links in a given directory to a particular
* inode. We do this so that ocfs2 can build a lock name which all
* nodes in the cluster can agree on at all times. Shoving full names
* in the cluster lock won't work due to size restrictions. Covering
* links inside of a directory is a good compromise because it still
* allows us to use the parent directory lock to synchronize
* operations.
*
* Call this function with the parent dir semaphore and the parent dir
* cluster lock held.
*
* The dir semaphore will protect us from having to worry about
* concurrent processes on our node trying to attach a lock at the
* same time.
*
* The dir cluster lock (held at either PR or EX mode) protects us
* from unlink and rename on other nodes.
*
* A dput() can happen asynchronously due to pruning, so we cover
* attaching and detaching the dentry lock with a
* dentry_attach_lock.
*
* A node which has done lookup on a name retains a protected read
* lock until final dput. If the user requests and unlink or rename,
* the protected read is upgraded to an exclusive lock. Other nodes
* who have seen the dentry will then be informed that they need to
* downgrade their lock, which will involve d_delete on the
* dentry. This happens in ocfs2_dentry_convert_worker().
*/
int ocfs2_dentry_attach_lock(struct dentry *dentry,
struct inode *inode,
u64 parent_blkno)
{
int ret;
struct dentry *alias;
struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name,
(unsigned long long)parent_blkno, dl);
/*
* Negative dentry. We ignore these for now.
*
* XXX: Could we can improve ocfs2_dentry_revalidate() by
* tracking these?
*/
if (!inode)
return 0;
if (d_really_is_negative(dentry) && dentry->d_fsdata) {
/* Converting a negative dentry to positive
Clear dentry->d_fsdata */
dentry->d_fsdata = dl = NULL;
}
if (dl) {
mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
" \"%pd\": old parent: %llu, new: %llu\n",
dentry,
(unsigned long long)parent_blkno,
(unsigned long long)dl->dl_parent_blkno);
return 0;
}
alias = ocfs2_find_local_alias(inode, parent_blkno, 0);
if (alias) {
/*
* Great, an alias exists, which means we must have a
* dentry lock already. We can just grab the lock off
* the alias and add it to the list.
*
* We're depending here on the fact that this dentry
* was found and exists in the dcache and so must have
* a reference to the dentry_lock because we can't
* race creates. Final dput() cannot happen on it
* since we have it pinned, so our reference is safe.
*/
dl = alias->d_fsdata;
mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n",
(unsigned long long)parent_blkno,
(unsigned long long)OCFS2_I(inode)->ip_blkno);
mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
" \"%pd\": old parent: %llu, new: %llu\n",
dentry,
(unsigned long long)parent_blkno,
(unsigned long long)dl->dl_parent_blkno);
trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name,
(unsigned long long)parent_blkno,
(unsigned long long)OCFS2_I(inode)->ip_blkno);
goto out_attach;
}
/*
* There are no other aliases
*/
dl = kmalloc(sizeof(*dl), GFP_NOFS);
if (!dl) {
ret = -ENOMEM;
mlog_errno(ret);
return ret;
}
dl->dl_count = 0;
/*
* Does this have to happen below, for all attaches, in case
* the struct inode gets blown away by the downconvert thread?
*/
dl->dl_inode = igrab(inode);
dl->dl_parent_blkno = parent_blkno;
ocfs2_dentry_lock_res_init(dl, parent_blkno, inode);
out_attach:
spin_lock(&dentry_attach_lock);
fs/ocfs2: fix race in ocfs2_dentry_attach_lock() ocfs2_dentry_attach_lock() can be executed in parallel threads against the same dentry. Make that race safe. The race is like this: thread A thread B (A1) enter ocfs2_dentry_attach_lock, seeing dentry->d_fsdata is NULL, and no alias found by ocfs2_find_local_alias, so kmalloc a new ocfs2_dentry_lock structure to local variable "dl", dl1 ..... (B1) enter ocfs2_dentry_attach_lock, seeing dentry->d_fsdata is NULL, and no alias found by ocfs2_find_local_alias so kmalloc a new ocfs2_dentry_lock structure to local variable "dl", dl2. ...... (A2) set dentry->d_fsdata with dl1, call ocfs2_dentry_lock() and increase dl1->dl_lockres.l_ro_holders to 1 on success. ...... (B2) set dentry->d_fsdata with dl2 call ocfs2_dentry_lock() and increase dl2->dl_lockres.l_ro_holders to 1 on success. ...... (A3) call ocfs2_dentry_unlock() and decrease dl2->dl_lockres.l_ro_holders to 0 on success. .... (B3) call ocfs2_dentry_unlock(), decreasing dl2->dl_lockres.l_ro_holders, but see it's zero now, panic Link: http://lkml.kernel.org/r/20190529174636.22364-1-wen.gang.wang@oracle.com Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com> Reported-by: Daniel Sobe <daniel.sobe@nxp.com> Tested-by: Daniel Sobe <daniel.sobe@nxp.com> Reviewed-by: Changwei Ge <gechangwei@live.cn> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-14 01:56:01 +03:00
if (unlikely(dentry->d_fsdata && !alias)) {
/* d_fsdata is set by a racing thread which is doing
* the same thing as this thread is doing. Leave the racing
* thread going ahead and we return here.
*/
spin_unlock(&dentry_attach_lock);
iput(dl->dl_inode);
ocfs2_lock_res_free(&dl->dl_lockres);
kfree(dl);
return 0;
}
dentry->d_fsdata = dl;
dl->dl_count++;
spin_unlock(&dentry_attach_lock);
/*
* This actually gets us our PRMODE level lock. From now on,
* we'll have a notification if one of these names is
* destroyed on another node.
*/
ret = ocfs2_dentry_lock(dentry, 0);
if (!ret)
ocfs2_dentry_unlock(dentry, 0);
else
mlog_errno(ret);
/*
* In case of error, manually free the allocation and do the iput().
* We need to do this because error here means no d_instantiate(),
* which means iput() will not be called during dput(dentry).
*/
if (ret < 0 && !alias) {
ocfs2_lock_res_free(&dl->dl_lockres);
BUG_ON(dl->dl_count != 1);
spin_lock(&dentry_attach_lock);
dentry->d_fsdata = NULL;
spin_unlock(&dentry_attach_lock);
kfree(dl);
iput(inode);
}
dput(alias);
return ret;
}
/*
* ocfs2_dentry_iput() and friends.
*
* At this point, our particular dentry is detached from the inodes
* alias list, so there's no way that the locking code can find it.
*
* The interesting stuff happens when we determine that our lock needs
* to go away because this is the last subdir alias in the
* system. This function needs to handle a couple things:
*
* 1) Synchronizing lock shutdown with the downconvert threads. This
* is already handled for us via the lockres release drop function
* called in ocfs2_release_dentry_lock()
*
* 2) A race may occur when we're doing our lock shutdown and
* another process wants to create a new dentry lock. Right now we
* let them race, which means that for a very short while, this
* node might have two locks on a lock resource. This should be a
* problem though because one of them is in the process of being
* thrown out.
*/
static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
struct ocfs2_dentry_lock *dl)
{
ocfs2: revert iput deferring code in ocfs2_drop_dentry_lock The following patches are reverted in this patch because these patches caused performance regression in the remote unlink() calls. ea455f8ab683 - ocfs2: Push out dropping of dentry lock to ocfs2_wq f7b1aa69be13 - ocfs2: Fix deadlock on umount 5fd131893793 - ocfs2: Don't oops in ocfs2_kill_sb on a failed mount Previous patches in this series removed the possible deadlocks from downconvert thread so the above patches shouldn't be needed anymore. The regression is caused because these patches delay the iput() in case of dentry unlocks. This also delays the unlocking of the open lockres. The open lockresource is required to test if the inode can be wiped from disk or not. When the deleting node does not get the open lock, it marks it as orphan (even though it is not in use by another node/process) and causes a journal checkpoint. This delays operations following the inode eviction. This also moves the inode to the orphaned inode which further causes more I/O and a lot of unneccessary orphans. The following script can be used to generate the load causing issues: declare -a create declare -a remove declare -a iterations=(1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384) unique="`mktemp -u XXXXX`" script="/tmp/idontknow-${unique}.sh" cat <<EOF > "${script}" for n in {1..8}; do mkdir -p test/dir\${n} eval touch test/dir\${n}/foo{1.."\$1"} done EOF chmod 700 "${script}" function fcreate () { exec 2>&1 /usr/bin/time --format=%E "${script}" "$1" } function fremove () { exec 2>&1 /usr/bin/time --format=%E ssh node2 "cd `pwd`; rm -Rf test*" } function fcp () { exec 2>&1 /usr/bin/time --format=%E ssh node3 "cd `pwd`; cp -R test test.new" } echo ------------------------------------------------- echo "| # files | create #s | copy #s | remove #s |" echo ------------------------------------------------- for ((x=0; x < ${#iterations[*]} ; x++)) do create[$x]="`fcreate ${iterations[$x]}`" copy[$x]="`fcp ${iterations[$x]}`" remove[$x]="`fremove`" printf "| %8d | %9s | %9s | %9s |\n" ${iterations[$x]} ${create[$x]} ${copy[$x]} ${remove[$x]} done rm "${script}" echo "------------------------" Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-04 01:46:59 +04:00
iput(dl->dl_inode);
ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
ocfs2_lock_res_free(&dl->dl_lockres);
ocfs2: revert iput deferring code in ocfs2_drop_dentry_lock The following patches are reverted in this patch because these patches caused performance regression in the remote unlink() calls. ea455f8ab683 - ocfs2: Push out dropping of dentry lock to ocfs2_wq f7b1aa69be13 - ocfs2: Fix deadlock on umount 5fd131893793 - ocfs2: Don't oops in ocfs2_kill_sb on a failed mount Previous patches in this series removed the possible deadlocks from downconvert thread so the above patches shouldn't be needed anymore. The regression is caused because these patches delay the iput() in case of dentry unlocks. This also delays the unlocking of the open lockres. The open lockresource is required to test if the inode can be wiped from disk or not. When the deleting node does not get the open lock, it marks it as orphan (even though it is not in use by another node/process) and causes a journal checkpoint. This delays operations following the inode eviction. This also moves the inode to the orphaned inode which further causes more I/O and a lot of unneccessary orphans. The following script can be used to generate the load causing issues: declare -a create declare -a remove declare -a iterations=(1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384) unique="`mktemp -u XXXXX`" script="/tmp/idontknow-${unique}.sh" cat <<EOF > "${script}" for n in {1..8}; do mkdir -p test/dir\${n} eval touch test/dir\${n}/foo{1.."\$1"} done EOF chmod 700 "${script}" function fcreate () { exec 2>&1 /usr/bin/time --format=%E "${script}" "$1" } function fremove () { exec 2>&1 /usr/bin/time --format=%E ssh node2 "cd `pwd`; rm -Rf test*" } function fcp () { exec 2>&1 /usr/bin/time --format=%E ssh node3 "cd `pwd`; cp -R test test.new" } echo ------------------------------------------------- echo "| # files | create #s | copy #s | remove #s |" echo ------------------------------------------------- for ((x=0; x < ${#iterations[*]} ; x++)) do create[$x]="`fcreate ${iterations[$x]}`" copy[$x]="`fcp ${iterations[$x]}`" remove[$x]="`fremove`" printf "| %8d | %9s | %9s | %9s |\n" ${iterations[$x]} ${create[$x]} ${copy[$x]} ${remove[$x]} done rm "${script}" echo "------------------------" Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-04 01:46:59 +04:00
kfree(dl);
}
void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
struct ocfs2_dentry_lock *dl)
{
ocfs2: revert iput deferring code in ocfs2_drop_dentry_lock The following patches are reverted in this patch because these patches caused performance regression in the remote unlink() calls. ea455f8ab683 - ocfs2: Push out dropping of dentry lock to ocfs2_wq f7b1aa69be13 - ocfs2: Fix deadlock on umount 5fd131893793 - ocfs2: Don't oops in ocfs2_kill_sb on a failed mount Previous patches in this series removed the possible deadlocks from downconvert thread so the above patches shouldn't be needed anymore. The regression is caused because these patches delay the iput() in case of dentry unlocks. This also delays the unlocking of the open lockres. The open lockresource is required to test if the inode can be wiped from disk or not. When the deleting node does not get the open lock, it marks it as orphan (even though it is not in use by another node/process) and causes a journal checkpoint. This delays operations following the inode eviction. This also moves the inode to the orphaned inode which further causes more I/O and a lot of unneccessary orphans. The following script can be used to generate the load causing issues: declare -a create declare -a remove declare -a iterations=(1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384) unique="`mktemp -u XXXXX`" script="/tmp/idontknow-${unique}.sh" cat <<EOF > "${script}" for n in {1..8}; do mkdir -p test/dir\${n} eval touch test/dir\${n}/foo{1.."\$1"} done EOF chmod 700 "${script}" function fcreate () { exec 2>&1 /usr/bin/time --format=%E "${script}" "$1" } function fremove () { exec 2>&1 /usr/bin/time --format=%E ssh node2 "cd `pwd`; rm -Rf test*" } function fcp () { exec 2>&1 /usr/bin/time --format=%E ssh node3 "cd `pwd`; cp -R test test.new" } echo ------------------------------------------------- echo "| # files | create #s | copy #s | remove #s |" echo ------------------------------------------------- for ((x=0; x < ${#iterations[*]} ; x++)) do create[$x]="`fcreate ${iterations[$x]}`" copy[$x]="`fcp ${iterations[$x]}`" remove[$x]="`fremove`" printf "| %8d | %9s | %9s | %9s |\n" ${iterations[$x]} ${create[$x]} ${copy[$x]} ${remove[$x]} done rm "${script}" echo "------------------------" Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-04 01:46:59 +04:00
int unlock = 0;
BUG_ON(dl->dl_count == 0);
spin_lock(&dentry_attach_lock);
dl->dl_count--;
unlock = !dl->dl_count;
spin_unlock(&dentry_attach_lock);
if (unlock)
ocfs2_drop_dentry_lock(osb, dl);
}
static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
{
struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
if (!dl) {
/*
* No dentry lock is ok if we're disconnected or
* unhashed.
*/
if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
!d_unhashed(dentry)) {
unsigned long long ino = 0ULL;
if (inode)
ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
mlog(ML_ERROR, "Dentry is missing cluster lock. "
"inode: %llu, d_flags: 0x%x, d_name: %pd\n",
ino, dentry->d_flags, dentry);
}
goto out;
}
mlog_bug_on_msg(dl->dl_count == 0, "dentry: %pd, count: %u\n",
dentry, dl->dl_count);
ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl);
out:
iput(inode);
}
/*
* d_move(), but keep the locks in sync.
*
* When we are done, "dentry" will have the parent dir and name of
* "target", which will be thrown away.
*
* We manually update the lock of "dentry" if need be.
*
* "target" doesn't have it's dentry lock touched - we allow the later
* dput() to handle this for us.
*
* This is called during ocfs2_rename(), while holding parent
* directory locks. The dentries have already been deleted on other
* nodes via ocfs2_remote_dentry_delete().
*
* Normally, the VFS handles the d_move() for the file system, after
* the ->rename() callback. OCFS2 wants to handle this internally, so
* the new lock can be created atomically with respect to the cluster.
*/
void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target,
struct inode *old_dir, struct inode *new_dir)
{
int ret;
struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb);
struct inode *inode = d_inode(dentry);
/*
* Move within the same directory, so the actual lock info won't
* change.
*
* XXX: Is there any advantage to dropping the lock here?
*/
if (old_dir == new_dir)
goto out_move;
ocfs2_dentry_lock_put(osb, dentry->d_fsdata);
dentry->d_fsdata = NULL;
ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno);
if (ret)
mlog_errno(ret);
out_move:
d_move(dentry, target);
}
const struct dentry_operations ocfs2_dentry_ops = {
.d_revalidate = ocfs2_dentry_revalidate,
.d_iput = ocfs2_dentry_iput,
};