diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2022-07-15 03:59:12 +0200 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-07-30 03:07:15 +0200 |
| commit | e408e695f5f1f60d784913afc45ff2c387a5aeb8 (patch) | |
| tree | 0a683ca610f0686e5e63d6291ef95ac63541a51b /mm/shmem.c | |
| parent | mm/damon/reclaim: fix potential memory leak in damon_reclaim_init() (diff) | |
| download | linux-e408e695f5f1f60d784913afc45ff2c387a5aeb8.tar.xz linux-e408e695f5f1f60d784913afc45ff2c387a5aeb8.zip | |
mm/shmem: support FS_IOC_[SG]ETFLAGS in tmpfs
This allows userspace to set flags like FS_APPEND_FL, FS_IMMUTABLE_FL,
FS_NODUMP_FL, etc., like all other standard Linux file systems.
[akpm@linux-foundation.org: fix CONFIG_TMPFS_XATTR=n warnings]
Link: https://lkml.kernel.org/r/20220715015912.2560575-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 64 |
1 files changed, 63 insertions, 1 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 12ac67dc831f..06871a913b49 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 & FS_APPEND_FL) + stat->attributes |= STATX_ATTR_APPEND; + if (info->fsflags & FS_IMMUTABLE_FL) + stat->attributes |= STATX_ATTR_IMMUTABLE; + if (info->fsflags & FS_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); @@ -3138,6 +3162,40 @@ static const char *shmem_get_link(struct dentry *dentry, } #ifdef CONFIG_TMPFS_XATTR + +static 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; +} + +static 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 = (info->fsflags & ~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; +} + /* * Superblocks without xattr inode operations may get some security.* xattr * support from the LSM "for free". As soon as we have any other xattrs @@ -3828,6 +3886,8 @@ 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 +3907,8 @@ 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, |