diff options
Diffstat (limited to 'ubuntu/aufs/f_op.c')
| -rw-r--r-- | ubuntu/aufs/f_op.c | 729 |
1 files changed, 729 insertions, 0 deletions
diff --git a/ubuntu/aufs/f_op.c b/ubuntu/aufs/f_op.c new file mode 100644 index 000000000000..942e71a7781c --- /dev/null +++ b/ubuntu/aufs/f_op.c @@ -0,0 +1,729 @@ +/* + * Copyright (C) 2005-2012 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, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/* + * file and vm operations + */ + +#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) +{ + int err; + aufs_bindex_t bindex; + struct file *h_file; + struct dentry *dentry; + struct au_finfo *finfo; + + FiMustWriteLock(file); + + dentry = file->f_dentry; + err = au_d_alive(dentry); + if (unlikely(err)) + goto out; + + finfo = au_fi(file); + memset(&finfo->fi_htop, 0, sizeof(finfo->fi_htop)); + atomic_set(&finfo->fi_mmapped, 0); + bindex = au_dbstart(dentry); + h_file = au_h_open(dentry, bindex, flags, file); + if (IS_ERR(h_file)) + err = PTR_ERR(h_file); + else { + au_set_fbstart(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; + + AuDbg("%.*s, f_flags 0x%x, f_mode 0x%x\n", + AuDLNPair(file->f_dentry), vfsub_file_flags(file), + file->f_mode); + + sb = file->f_dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH); + err = au_do_open(file, au_do_open_nondir, /*fidir*/NULL); + 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); + bindex = finfo->fi_btop; + if (bindex >= 0) { + /* remove me from sb->s_files */ + file_sb_list_del(file); + 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-mamagement (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. + */ + +static ssize_t aufs_read(struct file *file, char __user *buf, size_t count, + loff_t *ppos) +{ + ssize_t err; + struct dentry *dentry; + struct file *h_file; + struct super_block *sb; + + dentry = file->f_dentry; + sb = dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0); + if (unlikely(err)) + goto out; + + h_file = au_hf_top(file); + get_file(h_file); + di_read_unlock(dentry, AuLock_IR); + fi_read_unlock(file); + + /* 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; */ + /* update without lock, I don't think it a problem */ + fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode); + fput(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) { + mutex_lock(&inode->i_mutex); + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + if (!err) + break; + mutex_unlock(&inode->i_mutex); + 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_pin pin; + struct dentry *dentry; + struct super_block *sb; + struct inode *inode; + struct file *h_file; + char __user *buf = (char __user *)ubuf; + + dentry = file->f_dentry; + sb = dentry->d_sb; + inode = dentry->d_inode; + au_mtx_and_read_lock(inode); + + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out; + + err = au_ready_to_write(file, -1, &pin); + di_downgrade_lock(dentry, AuLock_IR); + if (unlikely(err)) { + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); + goto out; + } + + h_file = au_hf_top(file); + get_file(h_file); + au_unpin(&pin); + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); + + err = vfsub_write_u(h_file, buf, count, ppos); + ii_write_lock_child(inode); + au_cpup_attr_timesizes(inode); + inode->i_mode = h_file->f_dentry->d_inode->i_mode; + ii_write_unlock(inode); + fput(h_file); + +out: + si_read_unlock(sb); + mutex_unlock(&inode->i_mutex); + return err; +} + +static ssize_t au_do_aio(struct file *h_file, int rw, struct kiocb *kio, + const struct iovec *iov, unsigned long nv, loff_t pos) +{ + ssize_t err; + struct file *file; + ssize_t (*func)(struct kiocb *, const struct iovec *, unsigned long, + loff_t); + + err = security_file_permission(h_file, rw); + if (unlikely(err)) + goto out; + + err = -ENOSYS; + func = NULL; + if (rw == MAY_READ) + func = h_file->f_op->aio_read; + else if (rw == MAY_WRITE) + func = h_file->f_op->aio_write; + if (func) { + file = kio->ki_filp; + kio->ki_filp = h_file; + lockdep_off(); + err = func(kio, iov, nv, pos); + lockdep_on(); + kio->ki_filp = file; + } else + /* currently there is no such fs */ + WARN_ON_ONCE(1); + +out: + return err; +} + +static ssize_t aufs_aio_read(struct kiocb *kio, const struct iovec *iov, + unsigned long nv, loff_t pos) +{ + ssize_t err; + struct file *file, *h_file; + struct dentry *dentry; + struct super_block *sb; + + file = kio->ki_filp; + dentry = file->f_dentry; + sb = dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0); + if (unlikely(err)) + goto out; + + h_file = au_hf_top(file); + get_file(h_file); + di_read_unlock(dentry, AuLock_IR); + fi_read_unlock(file); + + err = au_do_aio(h_file, MAY_READ, kio, iov, nv, pos); + /* todo: necessary? */ + /* file->f_ra = h_file->f_ra; */ + /* update without lock, I don't think it a problem */ + fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode); + fput(h_file); + +out: + si_read_unlock(sb); + return err; +} + +static ssize_t aufs_aio_write(struct kiocb *kio, const struct iovec *iov, + unsigned long nv, loff_t pos) +{ + ssize_t err; + struct au_pin pin; + struct dentry *dentry; + struct inode *inode; + struct file *file, *h_file; + struct super_block *sb; + + file = kio->ki_filp; + dentry = file->f_dentry; + sb = dentry->d_sb; + inode = dentry->d_inode; + au_mtx_and_read_lock(inode); + + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out; + + err = au_ready_to_write(file, -1, &pin); + di_downgrade_lock(dentry, AuLock_IR); + if (unlikely(err)) { + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); + goto out; + } + + h_file = au_hf_top(file); + get_file(h_file); + au_unpin(&pin); + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); + + err = au_do_aio(h_file, MAY_WRITE, kio, iov, nv, pos); + ii_write_lock_child(inode); + au_cpup_attr_timesizes(inode); + inode->i_mode = h_file->f_dentry->d_inode->i_mode; + ii_write_unlock(inode); + fput(h_file); + +out: + si_read_unlock(sb); + mutex_unlock(&inode->i_mutex); + 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 dentry *dentry; + struct super_block *sb; + + dentry = file->f_dentry; + sb = dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0); + if (unlikely(err)) + goto out; + + err = -EINVAL; + h_file = au_hf_top(file); + get_file(h_file); + if (au_test_loopback_kthread()) { + au_warn_loopback(h_file->f_dentry->d_sb); + if (file->f_mapping != h_file->f_mapping) { + file->f_mapping = h_file->f_mapping; + smp_mb(); /* unnecessary? */ + } + } + di_read_unlock(dentry, AuLock_IR); + fi_read_unlock(file); + + err = vfsub_splice_to(h_file, ppos, pipe, len, flags); + /* todo: necessasry? */ + /* file->f_ra = h_file->f_ra; */ + /* update without lock, I don't think it a problem */ + fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode); + fput(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_pin pin; + struct dentry *dentry; + struct inode *inode; + struct file *h_file; + struct super_block *sb; + + dentry = file->f_dentry; + sb = dentry->d_sb; + inode = dentry->d_inode; + au_mtx_and_read_lock(inode); + + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out; + + err = au_ready_to_write(file, -1, &pin); + di_downgrade_lock(dentry, AuLock_IR); + if (unlikely(err)) { + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); + goto out; + } + + h_file = au_hf_top(file); + get_file(h_file); + au_unpin(&pin); + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); + + err = vfsub_splice_from(pipe, h_file, ppos, len, flags); + ii_write_lock_child(inode); + au_cpup_attr_timesizes(inode); + inode->i_mode = h_file->f_dentry->d_inode->i_mode; + ii_write_unlock(inode); + fput(h_file); + +out: + si_read_unlock(sb); + mutex_unlock(&inode->i_mutex); + return err; +} + +/* ---------------------------------------------------------------------- */ + +/* + * 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 definitly bad, but is not a problem since "si_rwsem for + * read" allows muliple 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_readdir() 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. + */ + +/* 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, EXECUTABLE) + | AuConv_VM_MAP(flags, LOCKED); +} + +static int aufs_mmap(struct file *file, struct vm_area_struct *vma) +{ + int err; + unsigned long prot; + aufs_bindex_t bstart; + const unsigned char wlock + = (file->f_mode & FMODE_WRITE) && (vma->vm_flags & VM_SHARED); + struct dentry *dentry; + struct super_block *sb; + struct file *h_file; + struct au_branch *br; + struct au_pin pin; + + AuDbgVmRegion(file, vma); + + dentry = file->f_dentry; + sb = dentry->d_sb; + lockdep_off(); + si_read_lock(sb, AuLock_NOPLMW); + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out; + + if (wlock) { + err = au_ready_to_write(file, -1, &pin); + di_write_unlock(dentry); + if (unlikely(err)) { + fi_write_unlock(file); + goto out; + } + au_unpin(&pin); + } else + di_write_unlock(dentry); + + bstart = au_fbstart(file); + br = au_sbr(sb, bstart); + h_file = au_hf_top(file); + get_file(h_file); + au_set_mmapped(file); + fi_write_unlock(file); + lockdep_on(); + + au_vm_file_reset(vma, h_file); + prot = au_prot_conv(vma->vm_flags); + err = security_file_mmap(h_file, /*reqprot*/prot, prot, + au_flag_conv(vma->vm_flags), vma->vm_start, 0); + if (!err) + err = h_file->f_op->mmap(h_file, vma); + if (unlikely(err)) + goto out_reset; + + au_vm_prfile_set(vma, file); + /* update without lock, I don't think it a problem */ + fsstack_copy_attr_atime(file->f_dentry->d_inode, + h_file->f_dentry->d_inode); + goto out_fput; /* success */ + +out_reset: + au_unset_mmapped(file); + au_vm_file_reset(vma, file); +out_fput: + fput(h_file); + lockdep_off(); +out: + 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_pin pin; + struct dentry *dentry; + struct inode *inode; + struct file *h_file; + struct super_block *sb; + + dentry = file->f_dentry; + inode = dentry->d_inode; + sb = dentry->d_sb; + mutex_lock(&inode->i_mutex); + err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); + if (unlikely(err)) + goto out; + + err = 0; /* -EBADF; */ /* posix? */ + if (unlikely(!(file->f_mode & FMODE_WRITE))) + goto out_si; + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out_si; + + err = au_ready_to_write(file, -1, &pin); + di_downgrade_lock(dentry, AuLock_IR); + if (unlikely(err)) + goto out_unlock; + au_unpin(&pin); + + err = -EINVAL; + h_file = au_hf_top(file); + err = vfsub_fsync(h_file, &h_file->f_path, datasync); + au_cpup_attr_timesizes(inode); + +out_unlock: + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); +out_si: + si_read_unlock(sb); +out: + mutex_unlock(&inode->i_mutex); + return err; +} + +/* no one supports this operation, currently */ +#if 0 +static int aufs_aio_fsync_nondir(struct kiocb *kio, int datasync) +{ + int err; + struct au_pin pin; + struct dentry *dentry; + struct inode *inode; + struct file *file, *h_file; + + file = kio->ki_filp; + dentry = file->f_dentry; + inode = dentry->d_inode; + au_mtx_and_read_lock(inode); + + err = 0; /* -EBADF; */ /* posix? */ + if (unlikely(!(file->f_mode & FMODE_WRITE))) + goto out; + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1); + if (unlikely(err)) + goto out; + + err = au_ready_to_write(file, -1, &pin); + di_downgrade_lock(dentry, AuLock_IR); + if (unlikely(err)) + goto out_unlock; + au_unpin(&pin); + + err = -ENOSYS; + h_file = au_hf_top(file); + if (h_file->f_op && h_file->f_op->aio_fsync) { + struct dentry *h_d; + struct mutex *h_mtx; + + h_d = h_file->f_dentry; + h_mtx = &h_d->d_inode->i_mutex; + if (!is_sync_kiocb(kio)) { + get_file(h_file); + fput(file); + } + kio->ki_filp = h_file; + err = h_file->f_op->aio_fsync(kio, datasync); + mutex_lock_nested(h_mtx, AuLsc_I_CHILD); + if (!err) + vfsub_update_h_iattr(&h_file->f_path, /*did*/NULL); + /*ignore*/ + au_cpup_attr_timesizes(inode); + mutex_unlock(h_mtx); + } + +out_unlock: + di_read_unlock(dentry, AuLock_IR); + fi_write_unlock(file); +out: + si_read_unlock(inode->sb); + mutex_unlock(&inode->i_mutex); + return err; +} +#endif + +static int aufs_fasync(int fd, struct file *file, int flag) +{ + int err; + struct file *h_file; + struct dentry *dentry; + struct super_block *sb; + + dentry = file->f_dentry; + sb = dentry->d_sb; + si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLMW); + err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0); + if (unlikely(err)) + goto out; + + h_file = au_hf_top(file); + if (h_file->f_op && h_file->f_op->fasync) + err = h_file->f_op->fasync(fd, h_file, flag); + + di_read_unlock(dentry, AuLock_IR); + fi_read_unlock(file); + +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, + .aio_read = aufs_aio_read, + .aio_write = aufs_aio_write, +#ifdef CONFIG_AUFS_POLL + .poll = aufs_poll, +#endif + .unlocked_ioctl = aufs_ioctl_nondir, +#ifdef CONFIG_COMPAT + .compat_ioctl = aufs_ioctl_nondir, /* same */ +#endif + .mmap = aufs_mmap, + .open = aufs_open_nondir, + .flush = aufs_flush_nondir, + .release = aufs_release_nondir, + .fsync = aufs_fsync_nondir, + /* .aio_fsync = aufs_aio_fsync_nondir, */ + .fasync = aufs_fasync, + /* .sendpage = aufs_sendpage, */ + .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 +}; |