mm/shmem: add support for FS_IOC_[SG]ETFLAGS for tmpfs

Message ID	20220713145234.2356641-1-tytso@mit.edu (mailing list archive)
State	New
Headers	show Return-Path: <owner-linux-mm@kvack.org> From: "Theodore Ts'o" <tytso@mit.edu> To: Hugh Dickins <hughd@google.com> Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, "Theodore Ts'o" <tytso@mit.edu> Subject: [PATCH] mm/shmem: add support for FS_IOC_[SG]ETFLAGS for tmpfs Date: Wed, 13 Jul 2022 10:52:34 -0400 Message-Id: <20220713145234.2356641-1-tytso@mit.edu> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	mm/shmem: add support for FS_IOC_[SG]ETFLAGS for tmpfs \| expand mm/shmem: add support for FS_IOC_[SG]ETFLAGS for tmpfs

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index a68f982f22d1..1b6c4013f691 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -25,9 +25,20 @@ struct shmem_inode_info { struct simple_xattrs xattrs; /* list of xattrs */ atomic_t stop_eviction; /* hold when working on inode */ struct timespec64 i_crtime; /* file creation time */ + unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */ struct inode vfs_inode; }; +#define SHMEM_FL_USER_VISIBLE FS_FL_USER_VISIBLE +#define SHMEM_FL_USER_MODIFIABLE FS_FL_USER_MODIFIABLE +#define SHMEM_FL_INHERITED FS_FL_USER_MODIFIABLE + +/* Flags that are appropriate for regular files (all but dir-specific ones). */ +#define SHMEM_REG_FLMASK (~(FS_DIRSYNC_FL | FS_TOPDIR_FL)) + +/* Flags that are appropriate for non-directories/regular files. */ +#define SHMEM_OTHER_FLMASK (FS_NODUMP_FL | FS_NOATIME_FL) + struct shmem_sb_info { unsigned long max_blocks; /* How many blocks are allowed */ struct percpu_counter used_blocks; /* How many are allocated */ diff --git a/mm/shmem.c b/mm/shmem.c index a6f565308133..515a2708d658 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -28,6 +28,7 @@ #include <linux/ramfs.h> #include <linux/pagemap.h> #include <linux/file.h> +#include <linux/fileattr.h> #include <linux/mm.h> #include <linux/random.h> #include <linux/sched/signal.h> @@ -1058,6 +1059,15 @@ static int shmem_getattr(struct user_namespace *mnt_userns, shmem_recalc_inode(inode); spin_unlock_irq(&info->lock); } + if (info->fsflags & EXT2_APPEND_FL) + stat->attributes |= STATX_ATTR_APPEND; + if (info->fsflags & EXT2_IMMUTABLE_FL) + stat->attributes |= STATX_ATTR_IMMUTABLE; + if (info->fsflags & EXT2_NODUMP_FL) + stat->attributes |= STATX_ATTR_NODUMP; + stat->attributes_mask |= (STATX_ATTR_APPEND | + STATX_ATTR_IMMUTABLE | + STATX_ATTR_NODUMP); generic_fillattr(&init_user_ns, inode, stat); if (shmem_is_huge(NULL, inode, 0)) @@ -2272,7 +2282,18 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) return 0; } -static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, +/* Mask out flags that are inappropriate for the given type of inode. */ +static unsigned shmem_mask_flags(umode_t mode, __u32 flags) +{ + if (S_ISDIR(mode)) + return flags; + else if (S_ISREG(mode)) + return flags & SHMEM_REG_FLMASK; + else + return flags & SHMEM_OTHER_FLMASK; +} + +static struct inode *shmem_get_inode(struct super_block *sb, struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { struct inode *inode; @@ -2297,6 +2318,9 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode info->seals = F_SEAL_SEAL; info->flags = flags & VM_NORESERVE; info->i_crtime = inode->i_mtime; + info->fsflags = (dir == NULL) ? 0 : + SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED; + info->fsflags = shmem_mask_flags(mode, info->fsflags); INIT_LIST_HEAD(&info->shrinklist); INIT_LIST_HEAD(&info->swaplist); simple_xattrs_init(&info->xattrs); @@ -2813,6 +2837,41 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, return error; } +int shmem_fileattr_get(struct dentry *dentry, struct fileattr *fa) +{ + struct shmem_inode_info *info = SHMEM_I(d_inode(dentry)); + + fileattr_fill_flags(fa, info->fsflags & SHMEM_FL_USER_VISIBLE); + + return 0; +} + + + +int shmem_fileattr_set(struct user_namespace *mnt_userns, + struct dentry *dentry, struct fileattr *fa) +{ + struct inode *inode = d_inode(dentry); + struct shmem_inode_info *info = SHMEM_I(inode); + + if (fileattr_has_fsx(fa)) + return -EOPNOTSUPP; + + info->fsflags = (fa->flags & ~SHMEM_FL_USER_MODIFIABLE) | + (fa->flags & SHMEM_FL_USER_MODIFIABLE); + + inode->i_flags &= ~(S_APPEND | S_IMMUTABLE | S_NOATIME); + if (info->fsflags & FS_APPEND_FL) + inode->i_flags |= S_APPEND; + if (info->fsflags & FS_IMMUTABLE_FL) + inode->i_flags |= S_IMMUTABLE; + if (info->fsflags & FS_NOATIME_FL) + inode->i_flags |= S_NOATIME; + + inode->i_ctime = current_time(inode); + return 0; +} + static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) { struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); @@ -3828,6 +3887,8 @@ static const struct inode_operations shmem_inode_operations = { #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, .set_acl = simple_set_acl, + .fileattr_get = shmem_fileattr_get, + .fileattr_set = shmem_fileattr_set, #endif }; @@ -3847,6 +3908,8 @@ static const struct inode_operations shmem_dir_inode_operations = { #endif #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, + .fileattr_get = shmem_fileattr_get, + .fileattr_set = shmem_fileattr_set, #endif #ifdef CONFIG_TMPFS_POSIX_ACL .setattr = shmem_setattr,

mm/shmem: add support for FS_IOC_[SG]ETFLAGS for tmpfs

Commit Message

Comments

Patch