udf: Protect default inode credentials by rwlock

Superblock carries credentials (uid, gid, etc.) which are used as default
values in __udf_read_inode() when media does not provide these. These
credentials can change during remount so we protect them by a rwlock so that
each inode gets a consistent set of credentials.

Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 9656907f4b81caf555ad086b11a213fadd419f75..fa3c1541151c114e856f32b2e1e187d689b3efb8 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1201,6 +1201,7 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
                return;
        }
 
+       read_lock(&sbi->s_cred_lock);
        inode->i_uid = le32_to_cpu(fe->uid);
        if (inode->i_uid == -1 ||
            UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_UID_IGNORE) ||
@@ -1213,13 +1214,6 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
            UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_GID_SET))
                inode->i_gid = UDF_SB(inode->i_sb)->s_gid;
 
-       inode->i_nlink = le16_to_cpu(fe->fileLinkCount);
-       if (!inode->i_nlink)
-               inode->i_nlink = 1;
-
-       inode->i_size = le64_to_cpu(fe->informationLength);
-       iinfo->i_lenExtents = inode->i_size;
-
        if (fe->icbTag.fileType != ICBTAG_FILE_TYPE_DIRECTORY &&
                        sbi->s_fmode != UDF_INVALID_MODE)
                inode->i_mode = sbi->s_fmode;
@@ -1229,6 +1223,14 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
        else
                inode->i_mode = udf_convert_permissions(fe);
        inode->i_mode &= ~sbi->s_umask;
+       read_unlock(&sbi->s_cred_lock);
+
+       inode->i_nlink = le16_to_cpu(fe->fileLinkCount);
+       if (!inode->i_nlink)
+               inode->i_nlink = 1;
+
+       inode->i_size = le64_to_cpu(fe->informationLength);
+       iinfo->i_lenExtents = inode->i_size;
 
        if (iinfo->i_efe == 0) {
                inode->i_blocks = le64_to_cpu(fe->logicalBlocksRecorded) <<

diff --git a/fs/udf/super.c b/fs/udf/super.c
index e54960c0e960560c8844d80e98553227bbbabae5..f06cc67cf864533f9b1724203da9f5755013d630 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -568,12 +568,14 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
                return -EINVAL;
 
        lock_kernel();
+       write_lock(&sbi->s_cred_lock);
        sbi->s_flags = uopt.flags;
        sbi->s_uid   = uopt.uid;
        sbi->s_gid   = uopt.gid;
        sbi->s_umask = uopt.umask;
        sbi->s_fmode = uopt.fmode;
        sbi->s_dmode = uopt.dmode;
+       write_unlock(&sbi->s_cred_lock);
 
        if (sbi->s_lvid_bh) {
                int write_rev = le16_to_cpu(udf_sb_lvidiu(sbi)->minUDFWriteRev);
@@ -1960,6 +1962,7 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
        sbi->s_fmode = uopt.fmode;
        sbi->s_dmode = uopt.dmode;
        sbi->s_nls_map = uopt.nls_map;
+       rwlock_init(&sbi->s_cred_lock);
 
        if (uopt.session == 0xFFFFFFFF)
                sbi->s_session = udf_get_last_session(sb);

diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 9f38a6ca4fd5ad866f209f4fb68212d751d4428a..4858c191242b7a4180f90b5e080606685b9cebb3 100644 (file)
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -129,6 +129,8 @@ struct udf_sb_info {
        uid_t                   s_uid;
        mode_t                  s_fmode;
        mode_t                  s_dmode;
+       /* Lock protecting consistency of above permission settings */
+       rwlock_t                s_cred_lock;
 
        /* Root Info */
        struct timespec         s_record_time;