| Message ID | 20210323195941.69720-4-andrealmeid@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: shmem: Add case-insensitive support for tmpfs | expand |
André Almeida <andrealmeid@collabora.com> writes: > Implement IOCTL operations for files to set/get file flags. Implement > the only supported flag by now, that is S_CASEFOLD. > > Signed-off-by: André Almeida <andrealmeid@collabora.com> > --- > include/linux/shmem_fs.h | 4 ++ > mm/shmem.c | 84 +++++++++++++++++++++++++++++++++++++++- > 2 files changed, 87 insertions(+), 1 deletion(-) > > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index 29ee64352807..2c89c5a66508 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -140,4 +140,8 @@ extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, > dst_addr) ({ BUG(); 0; }) > #endif > > +#define TMPFS_CASEFOLD_FL 0x40000000 /* Casefolded file */ > +#define TMPFS_USER_FLS TMPFS_CASEFOLD_FL /* Userspace supported flags */ > +#define TMPFS_FLS S_CASEFOLD /* Kernel supported flags */ Minor nit: FLS? _FLAGS is short enough :). > + > #endif > diff --git a/mm/shmem.c b/mm/shmem.c > index 20df81763995..2f2c996d215b 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -258,6 +258,7 @@ static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages) > static const struct super_operations shmem_ops; > const struct address_space_operations shmem_aops; > static const struct file_operations shmem_file_operations; > +static const struct file_operations shmem_dir_operations; > static const struct inode_operations shmem_inode_operations; > static const struct inode_operations shmem_dir_inode_operations; > static const struct inode_operations shmem_special_inode_operations; > @@ -2347,7 +2348,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode > /* Some things misbehave if size == 0 on a directory */ > inode->i_size = 2 * BOGO_DIRENT_SIZE; > inode->i_op = &shmem_dir_inode_operations; > - inode->i_fop = &simple_dir_operations; > + inode->i_fop = &shmem_dir_operations; > break; > case S_IFLNK: > /* > @@ -2838,6 +2839,76 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, > return error; > } > > +static long shmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > +{ > + int ret; > + u32 fsflags = 0, old, new = 0; > + struct inode *inode = file_inode(file); > + struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); > + > + switch (cmd) { > + case FS_IOC_GETFLAGS: > + if ((inode->i_flags & S_CASEFOLD) && S_ISDIR(inode->i_mode)) > + fsflags |= TMPFS_CASEFOLD_FL; > + > + if (put_user(fsflags, (int __user *)arg)) > + return -EFAULT; > + > + return 0; > + > + case FS_IOC_SETFLAGS: > + if (get_user(fsflags, (int __user *)arg)) > + return -EFAULT; > + > + old = inode->i_flags; > + > + if (fsflags & ~TMPFS_USER_FLS) > + return -EINVAL; > + > + if (fsflags & TMPFS_CASEFOLD_FL) { > + if (!sbinfo->casefold) { > + pr_err("tmpfs: casefold disabled at this mount point\n"); Minor nit: no point in logging an error here. The user has simply not enabled casefolding. The error returned below should be enough. > + return -EOPNOTSUPP; > + } > + > + if (!S_ISDIR(inode->i_mode)) > + return -ENOTDIR; > + > + if (!simple_empty(file_dentry(file))) > + return -ENOTEMPTY; > + > + new |= S_CASEFOLD; > + } else if (old & S_CASEFOLD) { > + if (!simple_empty(file_dentry(file))) > + return -ENOTEMPTY; > + } > + > + ret = mnt_want_write_file(file); > + if (ret) > + return ret; > + > + inode_lock(inode); > + > + ret = vfs_ioc_setflags_prepare(inode, old, new); > + if (ret) { > + inode_unlock(inode); > + mnt_drop_write_file(file); > + return ret; > + } > + > + inode_set_flags(inode, new, TMPFS_FLS); > + > + inode_unlock(inode); > + mnt_drop_write_file(file); > + return 0; > + > + default: > + return -ENOTTY; > + } > + > + return 0; > +} > + > static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) > { > struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); > @@ -3916,6 +3987,7 @@ static const struct file_operations shmem_file_operations = { > .splice_read = generic_file_splice_read, > .splice_write = iter_file_splice_write, > .fallocate = shmem_fallocate, > + .unlocked_ioctl = shmem_ioctl, > #endif > }; > > @@ -3928,6 +4000,16 @@ static const struct inode_operations shmem_inode_operations = { > #endif > }; > > +static const struct file_operations shmem_dir_operations = { > + .open = dcache_dir_open, > + .release = dcache_dir_close, > + .llseek = dcache_dir_lseek, > + .read = generic_read_dir, > + .iterate_shared = dcache_readdir, > + .fsync = noop_fsync, > + .unlocked_ioctl = shmem_ioctl, > +}; > + > static const struct inode_operations shmem_dir_inode_operations = { > #ifdef CONFIG_TMPFS > .create = shmem_create,
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 29ee64352807..2c89c5a66508 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -140,4 +140,8 @@ extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, dst_addr) ({ BUG(); 0; }) #endif +#define TMPFS_CASEFOLD_FL 0x40000000 /* Casefolded file */ +#define TMPFS_USER_FLS TMPFS_CASEFOLD_FL /* Userspace supported flags */ +#define TMPFS_FLS S_CASEFOLD /* Kernel supported flags */ + #endif diff --git a/mm/shmem.c b/mm/shmem.c index 20df81763995..2f2c996d215b 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -258,6 +258,7 @@ static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages) static const struct super_operations shmem_ops; const struct address_space_operations shmem_aops; static const struct file_operations shmem_file_operations; +static const struct file_operations shmem_dir_operations; static const struct inode_operations shmem_inode_operations; static const struct inode_operations shmem_dir_inode_operations; static const struct inode_operations shmem_special_inode_operations; @@ -2347,7 +2348,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode /* Some things misbehave if size == 0 on a directory */ inode->i_size = 2 * BOGO_DIRENT_SIZE; inode->i_op = &shmem_dir_inode_operations; - inode->i_fop = &simple_dir_operations; + inode->i_fop = &shmem_dir_operations; break; case S_IFLNK: /* @@ -2838,6 +2839,76 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, return error; } +static long shmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int ret; + u32 fsflags = 0, old, new = 0; + struct inode *inode = file_inode(file); + struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); + + switch (cmd) { + case FS_IOC_GETFLAGS: + if ((inode->i_flags & S_CASEFOLD) && S_ISDIR(inode->i_mode)) + fsflags |= TMPFS_CASEFOLD_FL; + + if (put_user(fsflags, (int __user *)arg)) + return -EFAULT; + + return 0; + + case FS_IOC_SETFLAGS: + if (get_user(fsflags, (int __user *)arg)) + return -EFAULT; + + old = inode->i_flags; + + if (fsflags & ~TMPFS_USER_FLS) + return -EINVAL; + + if (fsflags & TMPFS_CASEFOLD_FL) { + if (!sbinfo->casefold) { + pr_err("tmpfs: casefold disabled at this mount point\n"); + return -EOPNOTSUPP; + } + + if (!S_ISDIR(inode->i_mode)) + return -ENOTDIR; + + if (!simple_empty(file_dentry(file))) + return -ENOTEMPTY; + + new |= S_CASEFOLD; + } else if (old & S_CASEFOLD) { + if (!simple_empty(file_dentry(file))) + return -ENOTEMPTY; + } + + ret = mnt_want_write_file(file); + if (ret) + return ret; + + inode_lock(inode); + + ret = vfs_ioc_setflags_prepare(inode, old, new); + if (ret) { + inode_unlock(inode); + mnt_drop_write_file(file); + return ret; + } + + inode_set_flags(inode, new, TMPFS_FLS); + + inode_unlock(inode); + mnt_drop_write_file(file); + return 0; + + default: + return -ENOTTY; + } + + return 0; +} + static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) { struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); @@ -3916,6 +3987,7 @@ static const struct file_operations shmem_file_operations = { .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .fallocate = shmem_fallocate, + .unlocked_ioctl = shmem_ioctl, #endif }; @@ -3928,6 +4000,16 @@ static const struct inode_operations shmem_inode_operations = { #endif }; +static const struct file_operations shmem_dir_operations = { + .open = dcache_dir_open, + .release = dcache_dir_close, + .llseek = dcache_dir_lseek, + .read = generic_read_dir, + .iterate_shared = dcache_readdir, + .fsync = noop_fsync, + .unlocked_ioctl = shmem_ioctl, +}; + static const struct inode_operations shmem_dir_inode_operations = { #ifdef CONFIG_TMPFS .create = shmem_create,
Implement IOCTL operations for files to set/get file flags. Implement the only supported flag by now, that is S_CASEFOLD. Signed-off-by: André Almeida <andrealmeid@collabora.com> --- include/linux/shmem_fs.h | 4 ++ mm/shmem.c | 84 +++++++++++++++++++++++++++++++++++++++- 2 files changed, 87 insertions(+), 1 deletion(-)