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| author | Miklos Szeredi <mszeredi@suse.cz> | 2011-11-21 12:11:33 +0100 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-01-06 23:20:13 -0500 |
| commit | 8e8b87964bc8dc5c14b6543fc933b7725f07d3ac (patch) | |
| tree | 9a14c135741f3a8ba960ff97f060a58597604a6d /fs/namespace.c | |
| parent | 7ada4db88634429f4da690ad1c4eb73c93085f0c (diff) | |
| download | lwn-8e8b87964bc8dc5c14b6543fc933b7725f07d3ac.tar.gz lwn-8e8b87964bc8dc5c14b6543fc933b7725f07d3ac.zip | |
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.c | 7 |
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(); |