diff options
Diffstat (limited to 'fs/aufs/f_op.c')
| -rw-r--r-- | fs/aufs/f_op.c | 819 |
1 files changed, 819 insertions, 0 deletions
diff --git a/fs/aufs/f_op.c b/fs/aufs/f_op.c new file mode 100644 index 000000000000..5254b5cd3942 --- /dev/null +++ b/fs/aufs/f_op.c @@ -0,0 +1,819 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2005-2019 Junjiro R. Okajima + * + * This program, aufs is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * file and vm operations + */ + +#include <linux/aio.h> +#include <linux/fs_stack.h> +#include <linux/mman.h> +#include <linux/security.h> +#include "aufs.h" + +int au_do_open_nondir(struct file *file, int flags, struct file *h_file) +{ + int err; + aufs_bindex_t bindex; + struct dentry *dentry, *h_dentry; + struct au_finfo *finfo; + struct inode *h_inode; + + FiMustWriteLock(file); + + err = 0; + dentry = file->f_path.dentry; + AuDebugOn(IS_ERR_OR_NULL(dentry)); + finfo = au_fi(file); + memset(&finfo->fi_htop, 0, sizeof(finfo->fi_htop)); + atomic_set(&finfo->fi_mmapped, 0); + bindex = au_dbtop(dentry); + if (!h_file) { + h_dentry = au_h_dptr(dentry, bindex); + err = vfsub_test_mntns(file->f_path.mnt, h_dentry->d_sb); + if (unlikely(err)) + goto out; + h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0); + if (IS_ERR(h_file)) { + err = PTR_ERR(h_file); + goto out; + } + } else { + h_dentry = h_file->f_path.dentry; + err = vfsub_test_mntns(file->f_path.mnt, h_dentry->d_sb); + if (unlikely(err)) + goto out; + /* br ref is already inc-ed */ + } + + if ((flags & __O_TMPFILE) + && !(flags & O_EXCL)) { + h_inode = file_inode(h_file); + spin_lock(&h_inode->i_lock); + h_inode->i_state |= I_LINKABLE; + spin_unlock(&h_inode->i_lock); + } + au_set_fbtop(file, bindex); + au_set_h_fptr(file, bindex, h_file); + au_update_figen(file); + /* todo: necessary? */ + /* file->f_ra = h_file->f_ra; */ + +out: + return err; +} + +static int aufs_open_nondir(struct inode *inode __maybe_unused, + struct file *file) +{ + int err; + struct super_block *sb; + struct au_do_open_args args = { + .open = au_do_open_nondir + }; + + AuDbg("%pD, f_flags 0x%x, f_mode 0x%x\n", + file, vfsub_file_flags(file), file->f_mode); + + sb = file->f_path.dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH); + err = au_do_open(file, &args); + si_read_unlock(sb); + return err; +} + +int aufs_release_nondir(struct inode *inode __maybe_unused, struct file *file) +{ + struct au_finfo *finfo; + aufs_bindex_t bindex; + + finfo = au_fi(file); + au_hbl_del(&finfo->fi_hlist, + &au_sbi(file->f_path.dentry->d_sb)->si_files); + bindex = finfo->fi_btop; + if (bindex >= 0) + au_set_h_fptr(file, bindex, NULL); + + au_finfo_fin(file); + return 0; +} + +/* ---------------------------------------------------------------------- */ + +static int au_do_flush_nondir(struct file *file, fl_owner_t id) +{ + int err; + struct file *h_file; + + err = 0; + h_file = au_hf_top(file); + if (h_file) + err = vfsub_flush(h_file, id); + return err; +} + +static int aufs_flush_nondir(struct file *file, fl_owner_t id) +{ + return au_do_flush(file, id, au_do_flush_nondir); +} + +/* ---------------------------------------------------------------------- */ +/* + * read and write functions acquire [fdi]_rwsem once, but release before + * mmap_sem. This is because to stop a race condition between mmap(2). + * Releasing these aufs-rwsem should be safe, no branch-management (by keeping + * si_rwsem), no harmful copy-up should happen. Actually copy-up may happen in + * read functions after [fdi]_rwsem are released, but it should be harmless. + */ + +/* Callers should call au_read_post() or fput() in the end */ +struct file *au_read_pre(struct file *file, int keep_fi, unsigned int lsc) +{ + struct file *h_file; + int err; + + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0, lsc); + if (!err) { + di_read_unlock(file->f_path.dentry, AuLock_IR); + h_file = au_hf_top(file); + get_file(h_file); + if (!keep_fi) + fi_read_unlock(file); + } else + h_file = ERR_PTR(err); + + return h_file; +} + +static void au_read_post(struct inode *inode, struct file *h_file) +{ + /* update without lock, I don't think it a problem */ + fsstack_copy_attr_atime(inode, file_inode(h_file)); + fput(h_file); +} + +struct au_write_pre { + /* input */ + unsigned int lsc; + + /* output */ + blkcnt_t blks; + aufs_bindex_t btop; +}; + +/* + * return with iinfo is write-locked + * callers should call au_write_post() or iinfo_write_unlock() + fput() in the + * end + */ +static struct file *au_write_pre(struct file *file, int do_ready, + struct au_write_pre *wpre) +{ + struct file *h_file; + struct dentry *dentry; + int err; + unsigned int lsc; + struct au_pin pin; + + lsc = 0; + if (wpre) + lsc = wpre->lsc; + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1, lsc); + h_file = ERR_PTR(err); + if (unlikely(err)) + goto out; + + dentry = file->f_path.dentry; + if (do_ready) { + err = au_ready_to_write(file, -1, &pin); + if (unlikely(err)) { + h_file = ERR_PTR(err); + di_write_unlock(dentry); + goto out_fi; + } + } + + di_downgrade_lock(dentry, /*flags*/0); + if (wpre) + wpre->btop = au_fbtop(file); + h_file = au_hf_top(file); + get_file(h_file); + if (wpre) + wpre->blks = file_inode(h_file)->i_blocks; + if (do_ready) + au_unpin(&pin); + di_read_unlock(dentry, /*flags*/0); + +out_fi: + fi_write_unlock(file); +out: + return h_file; +} + +static void au_write_post(struct inode *inode, struct file *h_file, + struct au_write_pre *wpre, ssize_t written) +{ + struct inode *h_inode; + + au_cpup_attr_timesizes(inode); + AuDebugOn(au_ibtop(inode) != wpre->btop); + h_inode = file_inode(h_file); + inode->i_mode = h_inode->i_mode; + ii_write_unlock(inode); + /* AuDbg("blks %llu, %llu\n", (u64)blks, (u64)h_inode->i_blocks); */ + if (written > 0) + au_fhsm_wrote(inode->i_sb, wpre->btop, + /*force*/h_inode->i_blocks > wpre->blks); + fput(h_file); +} + +static ssize_t aufs_read(struct file *file, char __user *buf, size_t count, + loff_t *ppos) +{ + ssize_t err; + struct inode *inode; + struct file *h_file; + struct super_block *sb; + + inode = file_inode(file); + sb = inode->i_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + + h_file = au_read_pre(file, /*keep_fi*/0, /*lsc*/0); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + /* filedata may be obsoleted by concurrent copyup, but no problem */ + err = vfsub_read_u(h_file, buf, count, ppos); + /* todo: necessary? */ + /* file->f_ra = h_file->f_ra; */ + au_read_post(inode, h_file); + +out: + si_read_unlock(sb); + return err; +} + +/* + * todo: very ugly + * it locks both of i_mutex and si_rwsem for read in safe. + * if the plink maintenance mode continues forever (that is the problem), + * may loop forever. + */ +static void au_mtx_and_read_lock(struct inode *inode) +{ + int err; + struct super_block *sb = inode->i_sb; + + while (1) { + inode_lock(inode); + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + if (!err) + break; + inode_unlock(inode); + si_read_lock(sb, AuLock_NOPLMW); + si_read_unlock(sb); + } +} + +static ssize_t aufs_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + ssize_t err; + struct au_write_pre wpre; + struct inode *inode; + struct file *h_file; + char __user *buf = (char __user *)ubuf; + + inode = file_inode(file); + au_mtx_and_read_lock(inode); + + wpre.lsc = 0; + h_file = au_write_pre(file, /*do_ready*/1, &wpre); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + err = vfsub_write_u(h_file, buf, count, ppos); + au_write_post(inode, h_file, &wpre, err); + +out: + si_read_unlock(inode->i_sb); + inode_unlock(inode); + return err; +} + +static ssize_t au_do_iter(struct file *h_file, int rw, struct kiocb *kio, + struct iov_iter *iov_iter) +{ + ssize_t err; + struct file *file; + ssize_t (*iter)(struct kiocb *, struct iov_iter *); + + err = security_file_permission(h_file, rw); + if (unlikely(err)) + goto out; + + err = -ENOSYS; + iter = NULL; + if (rw == MAY_READ) + iter = h_file->f_op->read_iter; + else if (rw == MAY_WRITE) + iter = h_file->f_op->write_iter; + + file = kio->ki_filp; + kio->ki_filp = h_file; + if (iter) { + lockdep_off(); + err = iter(kio, iov_iter); + lockdep_on(); + } else + /* currently there is no such fs */ + WARN_ON_ONCE(1); + kio->ki_filp = file; + +out: + return err; +} + +static ssize_t aufs_read_iter(struct kiocb *kio, struct iov_iter *iov_iter) +{ + ssize_t err; + struct file *file, *h_file; + struct inode *inode; + struct super_block *sb; + + file = kio->ki_filp; + inode = file_inode(file); + sb = inode->i_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + + h_file = au_read_pre(file, /*keep_fi*/1, /*lsc*/0); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + if (au_test_loopback_kthread()) { + au_warn_loopback(h_file->f_path.dentry->d_sb); + if (file->f_mapping != h_file->f_mapping) { + file->f_mapping = h_file->f_mapping; + smp_mb(); /* unnecessary? */ + } + } + fi_read_unlock(file); + + err = au_do_iter(h_file, MAY_READ, kio, iov_iter); + /* todo: necessary? */ + /* file->f_ra = h_file->f_ra; */ + au_read_post(inode, h_file); + +out: + si_read_unlock(sb); + return err; +} + +static ssize_t aufs_write_iter(struct kiocb *kio, struct iov_iter *iov_iter) +{ + ssize_t err; + struct au_write_pre wpre; + struct inode *inode; + struct file *file, *h_file; + + file = kio->ki_filp; + inode = file_inode(file); + au_mtx_and_read_lock(inode); + + wpre.lsc = 0; + h_file = au_write_pre(file, /*do_ready*/1, &wpre); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + err = au_do_iter(h_file, MAY_WRITE, kio, iov_iter); + au_write_post(inode, h_file, &wpre, err); + +out: + si_read_unlock(inode->i_sb); + inode_unlock(inode); + return err; +} + +static ssize_t aufs_splice_read(struct file *file, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + ssize_t err; + struct file *h_file; + struct inode *inode; + struct super_block *sb; + + inode = file_inode(file); + sb = inode->i_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + + h_file = au_read_pre(file, /*keep_fi*/0, /*lsc*/0); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + err = vfsub_splice_to(h_file, ppos, pipe, len, flags); + /* todo: necessary? */ + /* file->f_ra = h_file->f_ra; */ + au_read_post(inode, h_file); + +out: + si_read_unlock(sb); + return err; +} + +static ssize_t +aufs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos, + size_t len, unsigned int flags) +{ + ssize_t err; + struct au_write_pre wpre; + struct inode *inode; + struct file *h_file; + + inode = file_inode(file); + au_mtx_and_read_lock(inode); + + wpre.lsc = 0; + h_file = au_write_pre(file, /*do_ready*/1, &wpre); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + err = vfsub_splice_from(pipe, h_file, ppos, len, flags); + au_write_post(inode, h_file, &wpre, err); + +out: + si_read_unlock(inode->i_sb); + inode_unlock(inode); + return err; +} + +static long aufs_fallocate(struct file *file, int mode, loff_t offset, + loff_t len) +{ + long err; + struct au_write_pre wpre; + struct inode *inode; + struct file *h_file; + + inode = file_inode(file); + au_mtx_and_read_lock(inode); + + wpre.lsc = 0; + h_file = au_write_pre(file, /*do_ready*/1, &wpre); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + lockdep_off(); + err = vfs_fallocate(h_file, mode, offset, len); + lockdep_on(); + au_write_post(inode, h_file, &wpre, /*written*/1); + +out: + si_read_unlock(inode->i_sb); + inode_unlock(inode); + return err; +} + +static ssize_t aufs_copy_file_range(struct file *src, loff_t src_pos, + struct file *dst, loff_t dst_pos, + size_t len, unsigned int flags) +{ + ssize_t err; + struct au_write_pre wpre; + enum { SRC, DST }; + struct { + struct inode *inode; + struct file *h_file; + struct super_block *h_sb; + } a[2]; +#define a_src a[SRC] +#define a_dst a[DST] + + err = -EINVAL; + a_src.inode = file_inode(src); + if (unlikely(!S_ISREG(a_src.inode->i_mode))) + goto out; + a_dst.inode = file_inode(dst); + if (unlikely(!S_ISREG(a_dst.inode->i_mode))) + goto out; + + au_mtx_and_read_lock(a_dst.inode); + /* + * in order to match the order in di_write_lock2_{child,parent}(), + * use f_path.dentry for this comparison. + */ + if (src->f_path.dentry < dst->f_path.dentry) { + a_src.h_file = au_read_pre(src, /*keep_fi*/1, AuLsc_FI_1); + err = PTR_ERR(a_src.h_file); + if (IS_ERR(a_src.h_file)) + goto out_si; + + wpre.lsc = AuLsc_FI_2; + a_dst.h_file = au_write_pre(dst, /*do_ready*/1, &wpre); + err = PTR_ERR(a_dst.h_file); + if (IS_ERR(a_dst.h_file)) { + au_read_post(a_src.inode, a_src.h_file); + goto out_si; + } + } else { + wpre.lsc = AuLsc_FI_1; + a_dst.h_file = au_write_pre(dst, /*do_ready*/1, &wpre); + err = PTR_ERR(a_dst.h_file); + if (IS_ERR(a_dst.h_file)) + goto out_si; + + a_src.h_file = au_read_pre(src, /*keep_fi*/1, AuLsc_FI_2); + err = PTR_ERR(a_src.h_file); + if (IS_ERR(a_src.h_file)) { + au_write_post(a_dst.inode, a_dst.h_file, &wpre, + /*written*/0); + goto out_si; + } + } + + err = -EXDEV; + a_src.h_sb = file_inode(a_src.h_file)->i_sb; + a_dst.h_sb = file_inode(a_dst.h_file)->i_sb; + if (unlikely(a_src.h_sb != a_dst.h_sb)) { + AuDbgFile(src); + AuDbgFile(dst); + goto out_file; + } + + err = vfsub_copy_file_range(a_src.h_file, src_pos, a_dst.h_file, + dst_pos, len, flags); + +out_file: + au_write_post(a_dst.inode, a_dst.h_file, &wpre, err); + fi_read_unlock(src); + au_read_post(a_src.inode, a_src.h_file); +out_si: + si_read_unlock(a_dst.inode->i_sb); + inode_unlock(a_dst.inode); +out: + return err; +#undef a_src +#undef a_dst +} + +/* ---------------------------------------------------------------------- */ + +/* + * The locking order around current->mmap_sem. + * - in most and regular cases + * file I/O syscall -- aufs_read() or something + * -- si_rwsem for read -- mmap_sem + * (Note that [fdi]i_rwsem are released before mmap_sem). + * - in mmap case + * mmap(2) -- mmap_sem -- aufs_mmap() -- si_rwsem for read -- [fdi]i_rwsem + * This AB-BA order is definitely bad, but is not a problem since "si_rwsem for + * read" allows multiple processes to acquire it and [fdi]i_rwsem are not held + * in file I/O. Aufs needs to stop lockdep in aufs_mmap() though. + * It means that when aufs acquires si_rwsem for write, the process should never + * acquire mmap_sem. + * + * Actually aufs_iterate() holds [fdi]i_rwsem before mmap_sem, but this is not a + * problem either since any directory is not able to be mmap-ed. + * The similar scenario is applied to aufs_readlink() too. + */ + +#if 0 /* stop calling security_file_mmap() */ +/* cf. linux/include/linux/mman.h: calc_vm_prot_bits() */ +#define AuConv_VM_PROT(f, b) _calc_vm_trans(f, VM_##b, PROT_##b) + +static unsigned long au_arch_prot_conv(unsigned long flags) +{ + /* currently ppc64 only */ +#ifdef CONFIG_PPC64 + /* cf. linux/arch/powerpc/include/asm/mman.h */ + AuDebugOn(arch_calc_vm_prot_bits(-1) != VM_SAO); + return AuConv_VM_PROT(flags, SAO); +#else + AuDebugOn(arch_calc_vm_prot_bits(-1)); + return 0; +#endif +} + +static unsigned long au_prot_conv(unsigned long flags) +{ + return AuConv_VM_PROT(flags, READ) + | AuConv_VM_PROT(flags, WRITE) + | AuConv_VM_PROT(flags, EXEC) + | au_arch_prot_conv(flags); +} + +/* cf. linux/include/linux/mman.h: calc_vm_flag_bits() */ +#define AuConv_VM_MAP(f, b) _calc_vm_trans(f, VM_##b, MAP_##b) + +static unsigned long au_flag_conv(unsigned long flags) +{ + return AuConv_VM_MAP(flags, GROWSDOWN) + | AuConv_VM_MAP(flags, DENYWRITE) + | AuConv_VM_MAP(flags, LOCKED); +} +#endif + +static int aufs_mmap(struct file *file, struct vm_area_struct *vma) +{ + int err; + const unsigned char wlock + = (file->f_mode & FMODE_WRITE) && (vma->vm_flags & VM_SHARED); + struct super_block *sb; + struct file *h_file; + struct inode *inode; + + AuDbgVmRegion(file, vma); + + inode = file_inode(file); + sb = inode->i_sb; + lockdep_off(); + si_read_lock(sb, AuLock_NOPLMW); + + h_file = au_write_pre(file, wlock, /*wpre*/NULL); + lockdep_on(); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + err = 0; + au_set_mmapped(file); + au_vm_file_reset(vma, h_file); + /* + * we cannot call security_mmap_file() here since it may acquire + * mmap_sem or i_mutex. + * + * err = security_mmap_file(h_file, au_prot_conv(vma->vm_flags), + * au_flag_conv(vma->vm_flags)); + */ + if (!err) + err = call_mmap(h_file, vma); + if (!err) { + au_vm_prfile_set(vma, file); + fsstack_copy_attr_atime(inode, file_inode(h_file)); + goto out_fput; /* success */ + } + au_unset_mmapped(file); + au_vm_file_reset(vma, file); + +out_fput: + lockdep_off(); + ii_write_unlock(inode); + lockdep_on(); + fput(h_file); +out: + lockdep_off(); + si_read_unlock(sb); + lockdep_on(); + AuTraceErr(err); + return err; +} + +/* ---------------------------------------------------------------------- */ + +static int aufs_fsync_nondir(struct file *file, loff_t start, loff_t end, + int datasync) +{ + int err; + struct au_write_pre wpre; + struct inode *inode; + struct file *h_file; + + err = 0; /* -EBADF; */ /* posix? */ + if (unlikely(!(file->f_mode & FMODE_WRITE))) + goto out; + + inode = file_inode(file); + au_mtx_and_read_lock(inode); + + wpre.lsc = 0; + h_file = au_write_pre(file, /*do_ready*/1, &wpre); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out_unlock; + + err = vfsub_fsync(h_file, &h_file->f_path, datasync); + au_write_post(inode, h_file, &wpre, /*written*/0); + +out_unlock: + si_read_unlock(inode->i_sb); + inode_unlock(inode); +out: + return err; +} + +static int aufs_fasync(int fd, struct file *file, int flag) +{ + int err; + struct file *h_file; + struct super_block *sb; + + sb = file->f_path.dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + + h_file = au_read_pre(file, /*keep_fi*/0, /*lsc*/0); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + if (h_file->f_op->fasync) + err = h_file->f_op->fasync(fd, h_file, flag); + fput(h_file); /* instead of au_read_post() */ + +out: + si_read_unlock(sb); + return err; +} + +static int aufs_setfl(struct file *file, unsigned long arg) +{ + int err; + struct file *h_file; + struct super_block *sb; + + sb = file->f_path.dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + + h_file = au_read_pre(file, /*keep_fi*/0, /*lsc*/0); + err = PTR_ERR(h_file); + if (IS_ERR(h_file)) + goto out; + + /* stop calling h_file->fasync */ + arg |= vfsub_file_flags(file) & FASYNC; + err = setfl(/*unused fd*/-1, h_file, arg); + fput(h_file); /* instead of au_read_post() */ + +out: + si_read_unlock(sb); + return err; +} + +/* ---------------------------------------------------------------------- */ + +/* no one supports this operation, currently */ +#if 0 +static ssize_t aufs_sendpage(struct file *file, struct page *page, int offset, + size_t len, loff_t *pos, int more) +{ +} +#endif + +/* ---------------------------------------------------------------------- */ + +const struct file_operations aufs_file_fop = { + .owner = THIS_MODULE, + + .llseek = default_llseek, + + .read = aufs_read, + .write = aufs_write, + .read_iter = aufs_read_iter, + .write_iter = aufs_write_iter, + +#ifdef CONFIG_AUFS_POLL + .poll = aufs_poll, +#endif + .unlocked_ioctl = aufs_ioctl_nondir, +#ifdef CONFIG_COMPAT + .compat_ioctl = aufs_compat_ioctl_nondir, +#endif + .mmap = aufs_mmap, + .open = aufs_open_nondir, + .flush = aufs_flush_nondir, + .release = aufs_release_nondir, + .fsync = aufs_fsync_nondir, + .fasync = aufs_fasync, + /* .sendpage = aufs_sendpage, */ + .setfl = aufs_setfl, + .splice_write = aufs_splice_write, + .splice_read = aufs_splice_read, +#if 0 + .aio_splice_write = aufs_aio_splice_write, + .aio_splice_read = aufs_aio_splice_read, +#endif + .fallocate = aufs_fallocate, + .copy_file_range = aufs_copy_file_range +}; |