From 08f11513fa6f712506edb99327f7d051da9d860f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 20 Feb 2009 05:56:19 +0000 Subject: constify dentry_operations: autofs, autofs4 Signed-off-by: Al Viro --- fs/autofs4/inode.c | 2 +- fs/autofs4/root.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/autofs4') diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c index 716e12b627b2..69c8142da838 100644 --- a/fs/autofs4/inode.c +++ b/fs/autofs4/inode.c @@ -310,7 +310,7 @@ static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi) return ino; } -static struct dentry_operations autofs4_sb_dentry_operations = { +static const struct dentry_operations autofs4_sb_dentry_operations = { .d_release = autofs4_dentry_release, }; diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 2a41c2a7fc52..74b1469a9504 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -349,13 +349,13 @@ void autofs4_dentry_release(struct dentry *de) } /* For dentries of directories in the root dir */ -static struct dentry_operations autofs4_root_dentry_operations = { +static const struct dentry_operations autofs4_root_dentry_operations = { .d_revalidate = autofs4_revalidate, .d_release = autofs4_dentry_release, }; /* For other dentries */ -static struct dentry_operations autofs4_dentry_operations = { +static const struct dentry_operations autofs4_dentry_operations = { .d_revalidate = autofs4_revalidate, .d_release = autofs4_dentry_release, }; -- cgit v1.2.2 From 56fcef75117a153f298b3fe54af31053f53997dd Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Tue, 31 Mar 2009 15:24:43 -0700 Subject: autofs4: cleanup expire code duplication A significant portion of the autofs_dev_ioctl_expire() and autofs4_expire_multi() functions is duplicated code. This patch cleans that up. Signed-off-by: Ian Kent Signed-off-by: Jeff Moyer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/autofs4/autofs_i.h | 2 ++ fs/autofs4/dev-ioctl.c | 29 +---------------------------- fs/autofs4/expire.c | 27 +++++++++++++++++---------- 3 files changed, 20 insertions(+), 38 deletions(-) (limited to 'fs/autofs4') diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h index a76803108d06..b7ff33c63101 100644 --- a/fs/autofs4/autofs_i.h +++ b/fs/autofs4/autofs_i.h @@ -186,6 +186,8 @@ int autofs4_expire_wait(struct dentry *dentry); int autofs4_expire_run(struct super_block *, struct vfsmount *, struct autofs_sb_info *, struct autofs_packet_expire __user *); +int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, + struct autofs_sb_info *sbi, int when); int autofs4_expire_multi(struct super_block *, struct vfsmount *, struct autofs_sb_info *, int __user *); struct dentry *autofs4_expire_direct(struct super_block *sb, diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c index 025e105bffea..9e5ae8a4f5c8 100644 --- a/fs/autofs4/dev-ioctl.c +++ b/fs/autofs4/dev-ioctl.c @@ -525,40 +525,13 @@ static int autofs_dev_ioctl_expire(struct file *fp, struct autofs_sb_info *sbi, struct autofs_dev_ioctl *param) { - struct dentry *dentry; struct vfsmount *mnt; - int err = -EAGAIN; int how; how = param->expire.how; mnt = fp->f_path.mnt; - if (autofs_type_trigger(sbi->type)) - dentry = autofs4_expire_direct(sbi->sb, mnt, sbi, how); - else - dentry = autofs4_expire_indirect(sbi->sb, mnt, sbi, how); - - if (dentry) { - struct autofs_info *ino = autofs4_dentry_ino(dentry); - - /* - * This is synchronous because it makes the daemon a - * little easier - */ - err = autofs4_wait(sbi, dentry, NFY_EXPIRE); - - spin_lock(&sbi->fs_lock); - if (ino->flags & AUTOFS_INF_MOUNTPOINT) { - ino->flags &= ~AUTOFS_INF_MOUNTPOINT; - sbi->sb->s_root->d_mounted++; - } - ino->flags &= ~AUTOFS_INF_EXPIRING; - complete_all(&ino->expire_complete); - spin_unlock(&sbi->fs_lock); - dput(dentry); - } - - return err; + return autofs4_do_expire_multi(sbi->sb, mnt, sbi, how); } /* Check if autofs mount point is in use */ diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index e3bd50776f9e..75f7ddacf7d6 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -478,22 +478,16 @@ int autofs4_expire_run(struct super_block *sb, return ret; } -/* Call repeatedly until it returns -EAGAIN, meaning there's nothing - more to be done */ -int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt, - struct autofs_sb_info *sbi, int __user *arg) +int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, + struct autofs_sb_info *sbi, int when) { struct dentry *dentry; int ret = -EAGAIN; - int do_now = 0; - - if (arg && get_user(do_now, arg)) - return -EFAULT; if (autofs_type_trigger(sbi->type)) - dentry = autofs4_expire_direct(sb, mnt, sbi, do_now); + dentry = autofs4_expire_direct(sb, mnt, sbi, when); else - dentry = autofs4_expire_indirect(sb, mnt, sbi, do_now); + dentry = autofs4_expire_indirect(sb, mnt, sbi, when); if (dentry) { struct autofs_info *ino = autofs4_dentry_ino(dentry); @@ -516,3 +510,16 @@ int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt, return ret; } +/* Call repeatedly until it returns -EAGAIN, meaning there's nothing + more to be done */ +int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt, + struct autofs_sb_info *sbi, int __user *arg) +{ + int do_now = 0; + + if (arg && get_user(do_now, arg)) + return -EFAULT; + + return autofs4_do_expire_multi(sb, mnt, sbi, do_now); +} + -- cgit v1.2.2 From 8f63aaa8b9239475fc580d4450f1141496655305 Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Tue, 31 Mar 2009 15:24:45 -0700 Subject: autofs4: fix lookup deadlock A deadlock can occur when user space uses a signal (autofs version 4 uses SIGCHLD for this) to effect expire completion. The order of events is: Expire process completes, but before being able to send SIGCHLD to it's parent ... Another process walks onto a different mount point and drops the directory inode semaphore prior to sending the request to the daemon as it must ... A third process does an lstat on on the expired mount point causing it to wait on expire completion (unfortunately) holding the directory semaphore. The mount request then arrives at the daemon which does an lstat and, deadlock. For some time I was concerned about releasing the directory semaphore around the expire wait in autofs4_lookup as well as for the mount call back. I finally realized that the last round of changes in this function made the expiring dentry and the lookup dentry separate and distinct so the check and possible wait can be done anywhere prior to the mount call back. This patch moves the check to just before the mount call back and inside the directory inode mutex release. Signed-off-by: Ian Kent Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/autofs4/root.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) (limited to 'fs/autofs4') diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 74b1469a9504..e383bf0334f1 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -485,22 +485,6 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode); - expiring = autofs4_lookup_expiring(sbi, dentry->d_parent, &dentry->d_name); - if (expiring) { - /* - * If we are racing with expire the request might not - * be quite complete but the directory has been removed - * so it must have been successful, so just wait for it. - */ - ino = autofs4_dentry_ino(expiring); - autofs4_expire_wait(expiring); - spin_lock(&sbi->lookup_lock); - if (!list_empty(&ino->expiring)) - list_del_init(&ino->expiring); - spin_unlock(&sbi->lookup_lock); - dput(expiring); - } - unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name); if (unhashed) dentry = unhashed; @@ -538,14 +522,31 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s } if (!oz_mode) { + mutex_unlock(&dir->i_mutex); + expiring = autofs4_lookup_expiring(sbi, + dentry->d_parent, + &dentry->d_name); + if (expiring) { + /* + * If we are racing with expire the request might not + * be quite complete but the directory has been removed + * so it must have been successful, so just wait for it. + */ + ino = autofs4_dentry_ino(expiring); + autofs4_expire_wait(expiring); + spin_lock(&sbi->lookup_lock); + if (!list_empty(&ino->expiring)) + list_del_init(&ino->expiring); + spin_unlock(&sbi->lookup_lock); + dput(expiring); + } + spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_AUTOFS_PENDING; spin_unlock(&dentry->d_lock); - if (dentry->d_op && dentry->d_op->d_revalidate) { - mutex_unlock(&dir->i_mutex); + if (dentry->d_op && dentry->d_op->d_revalidate) (dentry->d_op->d_revalidate)(dentry, nd); - mutex_lock(&dir->i_mutex); - } + mutex_lock(&dir->i_mutex); } /* -- cgit v1.2.2