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authorIan Kent <raven@themaw.net>2008-07-23 21:30:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-24 10:47:32 -0700
commit97e7449a7ad883bf9f516fc970778d75999c7843 (patch)
tree903f6de243847eb12d1a372b271b15046ecdc774 /fs/autofs4/autofs_i.h
parent26e81b3142f1ba497d4cd0365c13661684b784ce (diff)
downloadlinux-linaro-97e7449a7ad883bf9f516fc970778d75999c7843.tar.gz
autofs4: fix indirect mount pending expire race
The selection of a dentry for expiration and the setting of the AUTOFS_INF_EXPIRING flag isn't done atomically which can lead to lookups walking into an expiring mount. What happens is that an expire is initiated by the daemon and a dentry is selected for expire but, since there is no lock held between the selection and setting of the expiring flag, a process may find the flag clear and continue walking into the mount tree at the same time the daemon attempts the expire it. Signed-off-by: Ian Kent <raven@themaw.net> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/autofs4/autofs_i.h')
-rw-r--r--fs/autofs4/autofs_i.h10
1 files changed, 3 insertions, 7 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 058e1800cae..5d90ed3b4b4 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -138,18 +138,14 @@ static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
static inline int autofs4_ispending(struct dentry *dentry)
{
struct autofs_info *inf = autofs4_dentry_ino(dentry);
- int pending = 0;
if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
return 1;
- if (inf) {
- spin_lock(&inf->sbi->fs_lock);
- pending = inf->flags & AUTOFS_INF_EXPIRING;
- spin_unlock(&inf->sbi->fs_lock);
- }
+ if (inf->flags & AUTOFS_INF_EXPIRING)
+ return 1;
- return pending;
+ return 0;
}
static inline void autofs4_copy_atime(struct file *src, struct file *dst)