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authorIan Kent <raven@themaw.net>2005-05-01 11:59:17 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 11:59:17 -0400
commit3a9720ce73c9247e5262922d65e90444ea75eb50 (patch)
treec70bba916168232f530c00858e7e8a0c5bd82b38 /fs
parent4dcd00b18118d174c4b8d838c11f437f0af3c20c (diff)
[PATCH] autofs4: tree race fix
For tree mount maps, a call to chdir or chroot, to a directory above the moint point directories at a certain time during the expire results in the expire incorrectly thinking the tree is not busy. This patch adds a check to see if the filesystem above the tree mount points is busy and also locks the filesystem during the tree mount expire to prevent the race. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/autofs4/autofs_i.h14
-rw-r--r--fs/autofs4/expire.c16
-rw-r--r--fs/autofs4/inode.c1
3 files changed, 27 insertions, 4 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 978987735252..c7b2b8890188 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -102,6 +102,7 @@ struct autofs_sb_info {
102 int needs_reghost; 102 int needs_reghost;
103 struct super_block *sb; 103 struct super_block *sb;
104 struct semaphore wq_sem; 104 struct semaphore wq_sem;
105 spinlock_t fs_lock;
105 struct autofs_wait_queue *queues; /* Wait queue pointer */ 106 struct autofs_wait_queue *queues; /* Wait queue pointer */
106}; 107};
107 108
@@ -127,9 +128,18 @@ static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
127static inline int autofs4_ispending(struct dentry *dentry) 128static inline int autofs4_ispending(struct dentry *dentry)
128{ 129{
129 struct autofs_info *inf = autofs4_dentry_ino(dentry); 130 struct autofs_info *inf = autofs4_dentry_ino(dentry);
131 int pending = 0;
130 132
131 return (dentry->d_flags & DCACHE_AUTOFS_PENDING) || 133 if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
132 (inf != NULL && inf->flags & AUTOFS_INF_EXPIRING); 134 return 1;
135
136 if (inf) {
137 spin_lock(&inf->sbi->fs_lock);
138 pending = inf->flags & AUTOFS_INF_EXPIRING;
139 spin_unlock(&inf->sbi->fs_lock);
140 }
141
142 return pending;
133} 143}
134 144
135static inline void autofs4_copy_atime(struct file *src, struct file *dst) 145static inline void autofs4_copy_atime(struct file *src, struct file *dst)
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 31540a6404d9..500425e24fba 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -99,6 +99,10 @@ static int autofs4_check_tree(struct vfsmount *mnt,
99 if (!autofs4_can_expire(top, timeout, do_now)) 99 if (!autofs4_can_expire(top, timeout, do_now))
100 return 0; 100 return 0;
101 101
102 /* Is someone visiting anywhere in the tree ? */
103 if (may_umount_tree(mnt))
104 return 0;
105
102 spin_lock(&dcache_lock); 106 spin_lock(&dcache_lock);
103repeat: 107repeat:
104 next = this_parent->d_subdirs.next; 108 next = this_parent->d_subdirs.next;
@@ -270,10 +274,18 @@ static struct dentry *autofs4_expire(struct super_block *sb,
270 274
271 /* Case 2: tree mount, expire iff entire tree is not busy */ 275 /* Case 2: tree mount, expire iff entire tree is not busy */
272 if (!exp_leaves) { 276 if (!exp_leaves) {
277 /* Lock the tree as we must expire as a whole */
278 spin_lock(&sbi->fs_lock);
273 if (autofs4_check_tree(mnt, dentry, timeout, do_now)) { 279 if (autofs4_check_tree(mnt, dentry, timeout, do_now)) {
274 expired = dentry; 280 struct autofs_info *inf = autofs4_dentry_ino(dentry);
275 break; 281
282 /* Set this flag early to catch sys_chdir and the like */
283 inf->flags |= AUTOFS_INF_EXPIRING;
284 spin_unlock(&sbi->fs_lock);
285 expired = dentry;
286 break;
276 } 287 }
288 spin_unlock(&sbi->fs_lock);
277 /* Case 3: direct mount, expire individual leaves */ 289 /* Case 3: direct mount, expire individual leaves */
278 } else { 290 } else {
279 expired = autofs4_check_leaves(mnt, dentry, timeout, do_now); 291 expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index a52560746628..4bb14cc68040 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -206,6 +206,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
206 sbi->version = 0; 206 sbi->version = 0;
207 sbi->sub_version = 0; 207 sbi->sub_version = 0;
208 init_MUTEX(&sbi->wq_sem); 208 init_MUTEX(&sbi->wq_sem);
209 spin_lock_init(&sbi->fs_lock);
209 sbi->queues = NULL; 210 sbi->queues = NULL;
210 s->s_blocksize = 1024; 211 s->s_blocksize = 1024;
211 s->s_blocksize_bits = 10; 212 s->s_blocksize_bits = 10;