André Almeida <andrealmeid@xxxxxxxxxx> writes:
> Enable setting flag FS_CASEFOLD_FL for tmpfs directories, when tmpfs is
> mounted with casefold support. A special check is need for this flag,
> since it can't be set for non-empty directories.
Reviewed-by: Gabriel Krisman Bertazi <krisman@xxxxxxx>
>
> Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx>
> ---
> Changes from v2:
> - Fixed bug when adding a non-casefold flag in a non-empty dir
> ---
> include/linux/shmem_fs.h | 6 ++--
> mm/shmem.c | 70 ++++++++++++++++++++++++++++++++++++----
> 2 files changed, 67 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
> index 1d06b1e5408a..8367ca2b99d9 100644
> --- a/include/linux/shmem_fs.h
> +++ b/include/linux/shmem_fs.h
> @@ -42,10 +42,10 @@ struct shmem_inode_info {
> struct inode vfs_inode;
> };
>
> -#define SHMEM_FL_USER_VISIBLE FS_FL_USER_VISIBLE
> +#define SHMEM_FL_USER_VISIBLE (FS_FL_USER_VISIBLE | FS_CASEFOLD_FL)
> #define SHMEM_FL_USER_MODIFIABLE \
> - (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL)
> -#define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL)
> + (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL | FS_CASEFOLD_FL)
> +#define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL | FS_CASEFOLD_FL)
>
> struct shmem_quota_limits {
> qsize_t usrquota_bhardlimit; /* Default user quota block hard limit */
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 4fde63596ab3..fc0e0cd46146 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2613,13 +2613,62 @@ static int shmem_file_open(struct inode *inode, struct file *file)
> #ifdef CONFIG_TMPFS_XATTR
> static int shmem_initxattrs(struct inode *, const struct xattr *, void *);
>
> +#if IS_ENABLED(CONFIG_UNICODE)
> +/*
> + * shmem_inode_casefold_flags - Deal with casefold file attribute flag
> + *
> + * The casefold file attribute needs some special checks. I can just be added to
> + * an empty dir, and can't be removed from a non-empty dir.
> + */
> +static int shmem_inode_casefold_flags(struct inode *inode, unsigned int fsflags,
> + struct dentry *dentry, unsigned int *i_flags)
> +{
> + unsigned int old = inode->i_flags;
> + struct super_block *sb = inode->i_sb;
> +
> + if (fsflags & FS_CASEFOLD_FL) {
> + if (!(old & S_CASEFOLD)) {
> + if (!sb->s_encoding)
> + return -EOPNOTSUPP;
> +
> + if (!S_ISDIR(inode->i_mode))
> + return -ENOTDIR;
> +
> + if (dentry && !simple_empty(dentry))
> + return -ENOTEMPTY;
> + }
> +
> + *i_flags = *i_flags | S_CASEFOLD;
> + } else if (old & S_CASEFOLD) {
> + if (dentry && !simple_empty(dentry))
> + return -ENOTEMPTY;
> + }
> +
> + return 0;
> +}
> +#else
> +static int shmem_inode_casefold_flags(struct inode *inode, unsigned int fsflags,
> + struct dentry *dentry, unsigned int *i_flags)
> +{
> + if (fsflags & FS_CASEFOLD_FL)
> + return -EOPNOTSUPP;
> +
> + return 0;
> +}
> +#endif
> +
> /*
> * chattr's fsflags are unrelated to extended attributes,
> * but tmpfs has chosen to enable them under the same config option.
> */
> -static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
> +static int shmem_set_inode_flags(struct inode *inode, unsigned int fsflags, struct dentry *dentry)
> {
> unsigned int i_flags = 0;
> + int ret;
> +
> + ret = shmem_inode_casefold_flags(inode, fsflags, dentry, &i_flags);
> + if (ret)
> + return ret;
>
> if (fsflags & FS_NOATIME_FL)
> i_flags |= S_NOATIME;
> @@ -2630,10 +2679,12 @@ static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
> /*
> * But FS_NODUMP_FL does not require any action in i_flags.
> */
> - inode_set_flags(inode, i_flags, S_NOATIME | S_APPEND | S_IMMUTABLE);
> + inode_set_flags(inode, i_flags, S_NOATIME | S_APPEND | S_IMMUTABLE | S_CASEFOLD);
> +
> + return 0;
> }
> #else
> -static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
> +static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags, struct dentry *dentry)
> {
> }
> #define shmem_initxattrs NULL
> @@ -2680,7 +2731,7 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap,
> info->fsflags = (dir == NULL) ? 0 :
> SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
> if (info->fsflags)
> - shmem_set_inode_flags(inode, info->fsflags);
> + shmem_set_inode_flags(inode, info->fsflags, NULL);
> INIT_LIST_HEAD(&info->shrinklist);
> INIT_LIST_HEAD(&info->swaplist);
> simple_xattrs_init(&info->xattrs);
> @@ -3789,16 +3840,23 @@ static int shmem_fileattr_set(struct mnt_idmap *idmap,
> {
> struct inode *inode = d_inode(dentry);
> struct shmem_inode_info *info = SHMEM_I(inode);
> + int ret, flags;
>
> if (fileattr_has_fsx(fa))
> return -EOPNOTSUPP;
> if (fa->flags & ~SHMEM_FL_USER_MODIFIABLE)
> return -EOPNOTSUPP;
>
> - info->fsflags = (info->fsflags & ~SHMEM_FL_USER_MODIFIABLE) |
> + flags = (info->fsflags & ~SHMEM_FL_USER_MODIFIABLE) |
> (fa->flags & SHMEM_FL_USER_MODIFIABLE);
>
> - shmem_set_inode_flags(inode, info->fsflags);
> + ret = shmem_set_inode_flags(inode, flags, dentry);
> +
> + if (ret)
> + return ret;
> +
> + info->fsflags = flags;
> +
> inode_set_ctime_current(inode);
> inode_inc_iversion(inode);
> return 0;
--
Gabriel Krisman Bertazi
