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authorMiklos Szeredi <mszeredi@suse.cz>2011-11-21 15:11:33 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2012-01-07 08:20:13 +0400
commit8e8b87964bc8dc5c14b6543fc933b7725f07d3ac (patch)
tree9a14c135741f3a8ba960ff97f060a58597604a6d /fs/namespace.c
parent7ada4db88634429f4da690ad1c4eb73c93085f0c (diff)
downloadlinux-8e8b87964bc8dc5c14b6543fc933b7725f07d3ac.tar.xz
vfs: prevent remount read-only if pending removes
If there are any inodes on the super block that have been unlinked (i_nlink == 0) but have not yet been deleted then prevent the remounting the super block read-only. Reported-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 98ebc78b21ab..7e6f2c9dc7c4 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -449,6 +449,10 @@ int sb_prepare_remount_readonly(struct super_block *sb)
struct mount *mnt;
int err = 0;
+ /* Racy optimization. Recheck the counter under MNT_WRITE_HOLD */
+ if (atomic_long_read(&sb->s_remove_count))
+ return -EBUSY;
+
br_write_lock(vfsmount_lock);
list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
if (!(mnt->mnt.mnt_flags & MNT_READONLY)) {
@@ -460,6 +464,9 @@ int sb_prepare_remount_readonly(struct super_block *sb)
}
}
}
+ if (!err && atomic_long_read(&sb->s_remove_count))
+ err = -EBUSY;
+
if (!err) {
sb->s_readonly_remount = 1;
smp_wmb();