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author | Ian Kent <raven@themaw.net> | 2011-01-14 18:46:03 +0000 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2011-01-15 20:07:38 -0500 |
commit | b5b801779d59165c4ecf1009009109545bd1f642 (patch) | |
tree | 3a1c8b2e65e72977993ba96c1398edba4c63cbf5 /fs/autofs4/expire.c | |
parent | 10584211e48036182212b598cc53331776406d60 (diff) | |
download | linux-stable-b5b801779d59165c4ecf1009009109545bd1f642.tar.gz linux-stable-b5b801779d59165c4ecf1009009109545bd1f642.tar.bz2 linux-stable-b5b801779d59165c4ecf1009009109545bd1f642.zip |
autofs4: Add d_manage() dentry operation
This patch required a previous patch to add the ->d_automount()
dentry operation.
Add a function to use the newly defined ->d_manage() dentry operation
for blocking during mount and expire.
Whether the VFS calls the dentry operations d_automount() and d_manage()
is controled by the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags. autofs
uses the d_automount() operation to callback to user space to request
mount operations and the d_manage() operation to block walks into mounts
that are under construction or destruction.
In order to prevent these functions from being called unnecessarily the
DMANAGED_* flags are cleared for cases which would cause this. In the
common case the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags are both
set for dentrys waiting to be mounted. The DMANAGED_TRANSIT flag is
cleared upon successful mount request completion and set during expire
runs, both during the dentry expire check, and if selected for expire,
is left set until a subsequent successful mount request completes.
The exception to this is the so-called rootless multi-mount which has
no actual mount at its base. In this case the DMANAGED_AUTOMOUNT flag
is cleared upon successful mount request completion as well and set
again after a successful expire.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/autofs4/expire.c')
-rw-r--r-- | fs/autofs4/expire.c | 51 |
1 files changed, 26 insertions, 25 deletions
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index 0571ec8352b7..3ed79d76c233 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -26,10 +26,6 @@ static inline int autofs4_can_expire(struct dentry *dentry, if (ino == NULL) return 0; - /* No point expiring a pending mount */ - if (ino->flags & AUTOFS_INF_PENDING) - return 0; - if (!do_now) { /* Too young to die */ if (!timeout || time_after(ino->last_used + timeout, now)) @@ -283,6 +279,7 @@ struct dentry *autofs4_expire_direct(struct super_block *sb, unsigned long timeout; struct dentry *root = dget(sb->s_root); int do_now = how & AUTOFS_EXP_IMMEDIATE; + struct autofs_info *ino; if (!root) return NULL; @@ -291,20 +288,21 @@ struct dentry *autofs4_expire_direct(struct super_block *sb, timeout = sbi->exp_timeout; spin_lock(&sbi->fs_lock); + ino = autofs4_dentry_ino(root); + /* No point expiring a pending mount */ + if (ino->flags & AUTOFS_INF_PENDING) { + spin_unlock(&sbi->fs_lock); + return NULL; + } + managed_dentry_set_transit(root); if (!autofs4_direct_busy(mnt, root, timeout, do_now)) { struct autofs_info *ino = autofs4_dentry_ino(root); - if (d_mountpoint(root)) { - ino->flags |= AUTOFS_INF_MOUNTPOINT; - spin_lock(&root->d_lock); - root->d_flags &= ~DCACHE_MOUNTED; - spin_unlock(&root->d_lock); - } ino->flags |= AUTOFS_INF_EXPIRING; - managed_dentry_set_automount(root); init_completion(&ino->expire_complete); spin_unlock(&sbi->fs_lock); return root; } + managed_dentry_clear_transit(root); spin_unlock(&sbi->fs_lock); dput(root); @@ -341,6 +339,10 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, while ((dentry = get_next_positive_dentry(dentry, root))) { spin_lock(&sbi->fs_lock); ino = autofs4_dentry_ino(dentry); + /* No point expiring a pending mount */ + if (ino->flags & AUTOFS_INF_PENDING) + goto cont; + managed_dentry_set_transit(dentry); /* * Case 1: (i) indirect mount or top level pseudo direct mount @@ -400,6 +402,8 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, } } next: + managed_dentry_clear_transit(dentry); +cont: spin_unlock(&sbi->fs_lock); } return NULL; @@ -409,7 +413,6 @@ found: expired, (int)expired->d_name.len, expired->d_name.name); ino = autofs4_dentry_ino(expired); ino->flags |= AUTOFS_INF_EXPIRING; - managed_dentry_set_automount(expired); init_completion(&ino->expire_complete); spin_unlock(&sbi->fs_lock); spin_lock(&autofs4_lock); @@ -482,7 +485,7 @@ int autofs4_expire_run(struct super_block *sb, ino = autofs4_dentry_ino(dentry); ino->flags &= ~AUTOFS_INF_EXPIRING; if (!d_unhashed(dentry)) - managed_dentry_clear_automount(dentry); + managed_dentry_clear_transit(dentry); complete_all(&ino->expire_complete); spin_unlock(&sbi->fs_lock); @@ -508,20 +511,18 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, ret = autofs4_wait(sbi, dentry, NFY_EXPIRE); spin_lock(&sbi->fs_lock); - if (ino->flags & AUTOFS_INF_MOUNTPOINT) { - spin_lock(&sb->s_root->d_lock); - /* - * If we haven't been expired away, then reset - * mounted status. - */ - if (mnt->mnt_parent != mnt) - sb->s_root->d_flags |= DCACHE_MOUNTED; - spin_unlock(&sb->s_root->d_lock); - ino->flags &= ~AUTOFS_INF_MOUNTPOINT; - } ino->flags &= ~AUTOFS_INF_EXPIRING; + spin_lock(&dentry->d_lock); if (ret) - managed_dentry_clear_automount(dentry); + __managed_dentry_clear_transit(dentry); + else { + if ((IS_ROOT(dentry) || + (autofs_type_indirect(sbi->type) && + IS_ROOT(dentry->d_parent))) && + !(dentry->d_flags & DCACHE_NEED_AUTOMOUNT)) + __managed_dentry_set_automount(dentry); + } + spin_unlock(&dentry->d_lock); complete_all(&ino->expire_complete); spin_unlock(&sbi->fs_lock); dput(dentry); |