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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Linus Torvalds](/assets/img/avatar_default.png)
< XFS has gained super CoW powers! > ---------------------------------- \ ^__^ \ (oo)\_______ (__)\ )\/\ ||----w | || || Included in this update: - unshare range (FALLOC_FL_UNSHARE) support for fallocate - copy-on-write extent size hints (FS_XFLAG_COWEXTSIZE) for fsxattr interface - shared extent support for XFS - copy-on-write support for shared extents - copy_file_range support - clone_file_range support (implements reflink) - dedupe_file_range support - defrag support for reverse mapping enabled filesystems -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJX/hrZAAoJEK3oKUf0dfodpwcQAKkTerNPhhDcthqWUJ2+jC7w JIuhKUg2GYojJhIJ4+Ue1knmuBeIusda+PzGls+6gdy7GDGdux/esRIJSe1W7A5G RNeumiSKVX5iYsZNUEX35O2a/SwUM1Sm5mcIFs4CxUwIRwE/cayNby6vrlVExvz7 Ns6YYOI2bldUHLsxedg8MLG0it1JGTADB9gwGgb98bxQ3bD/UBn3TF9xTlj+ZH22 ebnWsogSJOnUigOOSGeaQsmy1pJAhRIhvt+f481KuZak1pdQcK2feL4RcKw0NpNt 15LCYRqX6RexC684VYgJZxXB4EKyfS2Bma71q41A7dz1x36kw7+wG18xasBqU++p GZwwL6si02rIGPMz1oD8xxZ0F97ADCGRmkgUHsCJKbP5UmGiP08K6GEN3osr5hAN xAmn9AxcprXVnV3WmnFxpBeWY/qCEsvSQqJuKSThYqAilqUc8wN2u5g/eEpE6mmg KEEhzaq5P4ovS/HOIQJWdBu1j5E9Mg2o/ncy87Q6uE+9Fa5AAP6GBWOtGcMwdFSU adbN7dqjgoHMyNHFrmePqyJYtOZ2hZovDlVndxnYysl5ZBfiBEEDISmr+x6KcSlo 3kyOltYQLjEVu1sLOT3COCddn0jt5Lr1QhGeVepnrMlU2E1h4461viCNMDinJRIp OYoMOS+J83G2FEFwgXYM =Sa+Y -----END PGP SIGNATURE----- Merge tag 'xfs-reflink-for-linus-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs < XFS has gained super CoW powers! > ---------------------------------- \ ^__^ \ (oo)\_______ (__)\ )\/\ ||----w | || || Pull XFS support for shared data extents from Dave Chinner: "This is the second part of the XFS updates for this merge cycle. This pullreq contains the new shared data extents feature for XFS. Given the complexity and size of this change I am expecting - like the addition of reverse mapping last cycle - that there will be some follow-up bug fixes and cleanups around the -rc3 stage for issues that I'm sure will show up once the code hits a wider userbase. What it is: At the most basic level we are simply adding shared data extents to XFS - i.e. a single extent on disk can now have multiple owners. To do this we have to add new on-disk features to both track the shared extents and the number of times they've been shared. This is done by the new "refcount" btree that sits in every allocation group. When we share or unshare an extent, this tree gets updated. Along with this new tree, the reverse mapping tree needs to be updated to track each owner or a shared extent. This also needs to be updated ever share/unshare operation. These interactions at extent allocation and freeing time have complex ordering and recovery constraints, so there's a significant amount of new intent-based transaction code to ensure that operations are performed atomically from both the runtime and integrity/crash recovery perspectives. We also need to break sharing when writes hit a shared extent - this is where the new copy-on-write implementation comes in. We allocate new storage and copy the original data along with the overwrite data into the new location. We only do this for data as we don't share metadata at all - each inode has it's own metadata that tracks the shared data extents, the extents undergoing CoW and it's own private extents. Of course, being XFS, nothing is simple - we use delayed allocation for CoW similar to how we use it for normal writes. ENOSPC is a significant issue here - we build on the reservation code added in 4.8-rc1 with the reverse mapping feature to ensure we don't get spurious ENOSPC issues part way through a CoW operation. These mechanisms also help minimise fragmentation due to repeated CoW operations. To further reduce fragmentation overhead, we've also introduced a CoW extent size hint, which indicates how large a region we should allocate when we execute a CoW operation. With all this functionality in place, we can hook up .copy_file_range, .clone_file_range and .dedupe_file_range and we gain all the capabilities of reflink and other vfs provided functionality that enable manipulation to shared extents. We also added a fallocate mode that explicitly unshares a range of a file, which we implemented as an explicit CoW of all the shared extents in a file. As such, it's a huge chunk of new functionality with new on-disk format features and internal infrastructure. It warns at mount time as an experimental feature and that it may eat data (as we do with all new on-disk features until they stabilise). We have not released userspace suport for it yet - userspace support currently requires download from Darrick's xfsprogs repo and build from source, so the access to this feature is really developer/tester only at this point. Initial userspace support will be released at the same time the kernel with this code in it is released. The new code causes 5-6 new failures with xfstests - these aren't serious functional failures but things the output of tests changing slightly due to perturbations in layouts, space usage, etc. OTOH, we've added 150+ new tests to xfstests that specifically exercise this new functionality so it's got far better test coverage than any functionality we've previously added to XFS. Darrick has done a pretty amazing job getting us to this stage, and special mention also needs to go to Christoph (review, testing, improvements and bug fixes) and Brian (caught several intricate bugs during review) for the effort they've also put in. Summary: - unshare range (FALLOC_FL_UNSHARE) support for fallocate - copy-on-write extent size hints (FS_XFLAG_COWEXTSIZE) for fsxattr interface - shared extent support for XFS - copy-on-write support for shared extents - copy_file_range support - clone_file_range support (implements reflink) - dedupe_file_range support - defrag support for reverse mapping enabled filesystems" * tag 'xfs-reflink-for-linus-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (71 commits) xfs: convert COW blocks to real blocks before unwritten extent conversion xfs: rework refcount cow recovery error handling xfs: clear reflink flag if setting realtime flag xfs: fix error initialization xfs: fix label inaccuracies xfs: remove isize check from unshare operation xfs: reduce stack usage of _reflink_clear_inode_flag xfs: check inode reflink flag before calling reflink functions xfs: implement swapext for rmap filesystems xfs: refactor swapext code xfs: various swapext cleanups xfs: recognize the reflink feature bit xfs: simulate per-AG reservations being critically low xfs: don't mix reflink and DAX mode for now xfs: check for invalid inode reflink flags xfs: set a default CoW extent size of 32 blocks xfs: convert unwritten status of reverse mappings for shared files xfs: use interval query for rmap alloc operations on shared files xfs: add shared rmap map/unmap/convert log item types xfs: increase log reservations for reflink ...
1182 lines
28 KiB
C
1182 lines
28 KiB
C
/*
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* linux/fs/open.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/fsnotify.h>
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#include <linux/module.h>
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#include <linux/tty.h>
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#include <linux/namei.h>
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#include <linux/backing-dev.h>
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#include <linux/capability.h>
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#include <linux/securebits.h>
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#include <linux/security.h>
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#include <linux/mount.h>
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#include <linux/fcntl.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include <linux/fs.h>
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#include <linux/personality.h>
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#include <linux/pagemap.h>
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#include <linux/syscalls.h>
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#include <linux/rcupdate.h>
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#include <linux/audit.h>
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#include <linux/falloc.h>
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#include <linux/fs_struct.h>
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#include <linux/ima.h>
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#include <linux/dnotify.h>
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#include <linux/compat.h>
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#include "internal.h"
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int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
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struct file *filp)
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{
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int ret;
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struct iattr newattrs;
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/* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
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if (length < 0)
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return -EINVAL;
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newattrs.ia_size = length;
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newattrs.ia_valid = ATTR_SIZE | time_attrs;
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if (filp) {
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newattrs.ia_file = filp;
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newattrs.ia_valid |= ATTR_FILE;
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}
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/* Remove suid, sgid, and file capabilities on truncate too */
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ret = dentry_needs_remove_privs(dentry);
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if (ret < 0)
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return ret;
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if (ret)
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newattrs.ia_valid |= ret | ATTR_FORCE;
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inode_lock(dentry->d_inode);
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/* Note any delegations or leases have already been broken: */
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ret = notify_change(dentry, &newattrs, NULL);
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inode_unlock(dentry->d_inode);
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return ret;
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}
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long vfs_truncate(const struct path *path, loff_t length)
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{
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struct inode *inode;
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struct dentry *upperdentry;
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long error;
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inode = path->dentry->d_inode;
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/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
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if (S_ISDIR(inode->i_mode))
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return -EISDIR;
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if (!S_ISREG(inode->i_mode))
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return -EINVAL;
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error = mnt_want_write(path->mnt);
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if (error)
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goto out;
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error = inode_permission(inode, MAY_WRITE);
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if (error)
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goto mnt_drop_write_and_out;
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error = -EPERM;
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if (IS_APPEND(inode))
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goto mnt_drop_write_and_out;
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/*
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* If this is an overlayfs then do as if opening the file so we get
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* write access on the upper inode, not on the overlay inode. For
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* non-overlay filesystems d_real() is an identity function.
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*/
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upperdentry = d_real(path->dentry, NULL, O_WRONLY);
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error = PTR_ERR(upperdentry);
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if (IS_ERR(upperdentry))
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goto mnt_drop_write_and_out;
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error = get_write_access(upperdentry->d_inode);
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if (error)
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goto mnt_drop_write_and_out;
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/*
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* Make sure that there are no leases. get_write_access() protects
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* against the truncate racing with a lease-granting setlease().
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*/
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error = break_lease(inode, O_WRONLY);
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if (error)
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goto put_write_and_out;
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error = locks_verify_truncate(inode, NULL, length);
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if (!error)
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error = security_path_truncate(path);
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if (!error)
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error = do_truncate(path->dentry, length, 0, NULL);
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put_write_and_out:
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put_write_access(upperdentry->d_inode);
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mnt_drop_write_and_out:
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mnt_drop_write(path->mnt);
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out:
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return error;
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}
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EXPORT_SYMBOL_GPL(vfs_truncate);
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static long do_sys_truncate(const char __user *pathname, loff_t length)
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{
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unsigned int lookup_flags = LOOKUP_FOLLOW;
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struct path path;
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int error;
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if (length < 0) /* sorry, but loff_t says... */
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return -EINVAL;
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retry:
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error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
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if (!error) {
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error = vfs_truncate(&path, length);
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path_put(&path);
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}
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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goto retry;
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}
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return error;
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}
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SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
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{
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return do_sys_truncate(path, length);
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}
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#ifdef CONFIG_COMPAT
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COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
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{
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return do_sys_truncate(path, length);
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}
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#endif
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static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
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{
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struct inode *inode;
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struct dentry *dentry;
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struct fd f;
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int error;
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error = -EINVAL;
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if (length < 0)
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goto out;
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error = -EBADF;
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f = fdget(fd);
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if (!f.file)
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goto out;
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/* explicitly opened as large or we are on 64-bit box */
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if (f.file->f_flags & O_LARGEFILE)
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small = 0;
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dentry = f.file->f_path.dentry;
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inode = dentry->d_inode;
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error = -EINVAL;
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if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
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goto out_putf;
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error = -EINVAL;
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/* Cannot ftruncate over 2^31 bytes without large file support */
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if (small && length > MAX_NON_LFS)
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goto out_putf;
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error = -EPERM;
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if (IS_APPEND(inode))
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goto out_putf;
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sb_start_write(inode->i_sb);
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error = locks_verify_truncate(inode, f.file, length);
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if (!error)
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error = security_path_truncate(&f.file->f_path);
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if (!error)
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error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
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sb_end_write(inode->i_sb);
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out_putf:
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fdput(f);
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out:
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return error;
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}
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SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
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{
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return do_sys_ftruncate(fd, length, 1);
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}
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#ifdef CONFIG_COMPAT
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COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
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{
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return do_sys_ftruncate(fd, length, 1);
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}
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#endif
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/* LFS versions of truncate are only needed on 32 bit machines */
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#if BITS_PER_LONG == 32
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SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
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{
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return do_sys_truncate(path, length);
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}
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SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
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{
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return do_sys_ftruncate(fd, length, 0);
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}
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#endif /* BITS_PER_LONG == 32 */
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int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
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{
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struct inode *inode = file_inode(file);
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long ret;
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if (offset < 0 || len <= 0)
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return -EINVAL;
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/* Return error if mode is not supported */
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if (mode & ~FALLOC_FL_SUPPORTED_MASK)
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return -EOPNOTSUPP;
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/* Punch hole and zero range are mutually exclusive */
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if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
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(FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
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return -EOPNOTSUPP;
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/* Punch hole must have keep size set */
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if ((mode & FALLOC_FL_PUNCH_HOLE) &&
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!(mode & FALLOC_FL_KEEP_SIZE))
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return -EOPNOTSUPP;
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/* Collapse range should only be used exclusively. */
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if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
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(mode & ~FALLOC_FL_COLLAPSE_RANGE))
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return -EINVAL;
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/* Insert range should only be used exclusively. */
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if ((mode & FALLOC_FL_INSERT_RANGE) &&
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(mode & ~FALLOC_FL_INSERT_RANGE))
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return -EINVAL;
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/* Unshare range should only be used with allocate mode. */
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if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
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(mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
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return -EINVAL;
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if (!(file->f_mode & FMODE_WRITE))
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return -EBADF;
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/*
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* We can only allow pure fallocate on append only files
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*/
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if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
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return -EPERM;
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if (IS_IMMUTABLE(inode))
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return -EPERM;
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/*
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* We cannot allow any fallocate operation on an active swapfile
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*/
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if (IS_SWAPFILE(inode))
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return -ETXTBSY;
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/*
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* Revalidate the write permissions, in case security policy has
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* changed since the files were opened.
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*/
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ret = security_file_permission(file, MAY_WRITE);
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if (ret)
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return ret;
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if (S_ISFIFO(inode->i_mode))
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return -ESPIPE;
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/*
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* Let individual file system decide if it supports preallocation
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* for directories or not.
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*/
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if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode) &&
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!S_ISBLK(inode->i_mode))
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return -ENODEV;
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/* Check for wrap through zero too */
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if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
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return -EFBIG;
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if (!file->f_op->fallocate)
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return -EOPNOTSUPP;
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sb_start_write(inode->i_sb);
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ret = file->f_op->fallocate(file, mode, offset, len);
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/*
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* Create inotify and fanotify events.
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*
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* To keep the logic simple always create events if fallocate succeeds.
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* This implies that events are even created if the file size remains
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* unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
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*/
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if (ret == 0)
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fsnotify_modify(file);
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sb_end_write(inode->i_sb);
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return ret;
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}
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EXPORT_SYMBOL_GPL(vfs_fallocate);
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SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
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{
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struct fd f = fdget(fd);
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int error = -EBADF;
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|
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if (f.file) {
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error = vfs_fallocate(f.file, mode, offset, len);
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fdput(f);
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}
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return error;
|
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}
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|
|
/*
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* access() needs to use the real uid/gid, not the effective uid/gid.
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* We do this by temporarily clearing all FS-related capabilities and
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* switching the fsuid/fsgid around to the real ones.
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*/
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SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
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{
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const struct cred *old_cred;
|
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struct cred *override_cred;
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struct path path;
|
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struct inode *inode;
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int res;
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unsigned int lookup_flags = LOOKUP_FOLLOW;
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|
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if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
|
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return -EINVAL;
|
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|
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override_cred = prepare_creds();
|
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if (!override_cred)
|
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return -ENOMEM;
|
|
|
|
override_cred->fsuid = override_cred->uid;
|
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override_cred->fsgid = override_cred->gid;
|
|
|
|
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
|
|
/* Clear the capabilities if we switch to a non-root user */
|
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kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
|
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if (!uid_eq(override_cred->uid, root_uid))
|
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cap_clear(override_cred->cap_effective);
|
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else
|
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override_cred->cap_effective =
|
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override_cred->cap_permitted;
|
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}
|
|
|
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old_cred = override_creds(override_cred);
|
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retry:
|
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res = user_path_at(dfd, filename, lookup_flags, &path);
|
|
if (res)
|
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goto out;
|
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|
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inode = d_backing_inode(path.dentry);
|
|
|
|
if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
|
|
/*
|
|
* MAY_EXEC on regular files is denied if the fs is mounted
|
|
* with the "noexec" flag.
|
|
*/
|
|
res = -EACCES;
|
|
if (path_noexec(&path))
|
|
goto out_path_release;
|
|
}
|
|
|
|
res = inode_permission(inode, mode | MAY_ACCESS);
|
|
/* SuS v2 requires we report a read only fs too */
|
|
if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
|
|
goto out_path_release;
|
|
/*
|
|
* This is a rare case where using __mnt_is_readonly()
|
|
* is OK without a mnt_want/drop_write() pair. Since
|
|
* no actual write to the fs is performed here, we do
|
|
* not need to telegraph to that to anyone.
|
|
*
|
|
* By doing this, we accept that this access is
|
|
* inherently racy and know that the fs may change
|
|
* state before we even see this result.
|
|
*/
|
|
if (__mnt_is_readonly(path.mnt))
|
|
res = -EROFS;
|
|
|
|
out_path_release:
|
|
path_put(&path);
|
|
if (retry_estale(res, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
revert_creds(old_cred);
|
|
put_cred(override_cred);
|
|
return res;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
|
|
{
|
|
return sys_faccessat(AT_FDCWD, filename, mode);
|
|
}
|
|
|
|
SYSCALL_DEFINE1(chdir, const char __user *, filename)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
|
|
if (error)
|
|
goto dput_and_out;
|
|
|
|
set_fs_pwd(current->fs, &path);
|
|
|
|
dput_and_out:
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(fchdir, unsigned int, fd)
|
|
{
|
|
struct fd f = fdget_raw(fd);
|
|
struct inode *inode;
|
|
int error = -EBADF;
|
|
|
|
error = -EBADF;
|
|
if (!f.file)
|
|
goto out;
|
|
|
|
inode = file_inode(f.file);
|
|
|
|
error = -ENOTDIR;
|
|
if (!S_ISDIR(inode->i_mode))
|
|
goto out_putf;
|
|
|
|
error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
|
|
if (!error)
|
|
set_fs_pwd(current->fs, &f.file->f_path);
|
|
out_putf:
|
|
fdput(f);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(chroot, const char __user *, filename)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
|
|
if (error)
|
|
goto dput_and_out;
|
|
|
|
error = -EPERM;
|
|
if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
|
|
goto dput_and_out;
|
|
error = security_path_chroot(&path);
|
|
if (error)
|
|
goto dput_and_out;
|
|
|
|
set_fs_root(current->fs, &path);
|
|
error = 0;
|
|
dput_and_out:
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static int chmod_common(const struct path *path, umode_t mode)
|
|
{
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct inode *delegated_inode = NULL;
|
|
struct iattr newattrs;
|
|
int error;
|
|
|
|
error = mnt_want_write(path->mnt);
|
|
if (error)
|
|
return error;
|
|
retry_deleg:
|
|
inode_lock(inode);
|
|
error = security_path_chmod(path, mode);
|
|
if (error)
|
|
goto out_unlock;
|
|
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
|
|
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
|
|
error = notify_change(path->dentry, &newattrs, &delegated_inode);
|
|
out_unlock:
|
|
inode_unlock(inode);
|
|
if (delegated_inode) {
|
|
error = break_deleg_wait(&delegated_inode);
|
|
if (!error)
|
|
goto retry_deleg;
|
|
}
|
|
mnt_drop_write(path->mnt);
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int err = -EBADF;
|
|
|
|
if (f.file) {
|
|
audit_file(f.file);
|
|
err = chmod_common(&f.file->f_path, mode);
|
|
fdput(f);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
unsigned int lookup_flags = LOOKUP_FOLLOW;
|
|
retry:
|
|
error = user_path_at(dfd, filename, lookup_flags, &path);
|
|
if (!error) {
|
|
error = chmod_common(&path, mode);
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
|
|
{
|
|
return sys_fchmodat(AT_FDCWD, filename, mode);
|
|
}
|
|
|
|
static int chown_common(const struct path *path, uid_t user, gid_t group)
|
|
{
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct inode *delegated_inode = NULL;
|
|
int error;
|
|
struct iattr newattrs;
|
|
kuid_t uid;
|
|
kgid_t gid;
|
|
|
|
uid = make_kuid(current_user_ns(), user);
|
|
gid = make_kgid(current_user_ns(), group);
|
|
|
|
retry_deleg:
|
|
newattrs.ia_valid = ATTR_CTIME;
|
|
if (user != (uid_t) -1) {
|
|
if (!uid_valid(uid))
|
|
return -EINVAL;
|
|
newattrs.ia_valid |= ATTR_UID;
|
|
newattrs.ia_uid = uid;
|
|
}
|
|
if (group != (gid_t) -1) {
|
|
if (!gid_valid(gid))
|
|
return -EINVAL;
|
|
newattrs.ia_valid |= ATTR_GID;
|
|
newattrs.ia_gid = gid;
|
|
}
|
|
if (!S_ISDIR(inode->i_mode))
|
|
newattrs.ia_valid |=
|
|
ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
|
|
inode_lock(inode);
|
|
error = security_path_chown(path, uid, gid);
|
|
if (!error)
|
|
error = notify_change(path->dentry, &newattrs, &delegated_inode);
|
|
inode_unlock(inode);
|
|
if (delegated_inode) {
|
|
error = break_deleg_wait(&delegated_inode);
|
|
if (!error)
|
|
goto retry_deleg;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
|
|
gid_t, group, int, flag)
|
|
{
|
|
struct path path;
|
|
int error = -EINVAL;
|
|
int lookup_flags;
|
|
|
|
if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
|
|
goto out;
|
|
|
|
lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
|
|
if (flag & AT_EMPTY_PATH)
|
|
lookup_flags |= LOOKUP_EMPTY;
|
|
retry:
|
|
error = user_path_at(dfd, filename, lookup_flags, &path);
|
|
if (error)
|
|
goto out;
|
|
error = mnt_want_write(path.mnt);
|
|
if (error)
|
|
goto out_release;
|
|
error = chown_common(&path, user, group);
|
|
mnt_drop_write(path.mnt);
|
|
out_release:
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
|
|
{
|
|
return sys_fchownat(AT_FDCWD, filename, user, group, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
|
|
{
|
|
return sys_fchownat(AT_FDCWD, filename, user, group,
|
|
AT_SYMLINK_NOFOLLOW);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int error = -EBADF;
|
|
|
|
if (!f.file)
|
|
goto out;
|
|
|
|
error = mnt_want_write_file(f.file);
|
|
if (error)
|
|
goto out_fput;
|
|
audit_file(f.file);
|
|
error = chown_common(&f.file->f_path, user, group);
|
|
mnt_drop_write_file(f.file);
|
|
out_fput:
|
|
fdput(f);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
int open_check_o_direct(struct file *f)
|
|
{
|
|
/* NB: we're sure to have correct a_ops only after f_op->open */
|
|
if (f->f_flags & O_DIRECT) {
|
|
if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int do_dentry_open(struct file *f,
|
|
struct inode *inode,
|
|
int (*open)(struct inode *, struct file *),
|
|
const struct cred *cred)
|
|
{
|
|
static const struct file_operations empty_fops = {};
|
|
int error;
|
|
|
|
f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
|
|
FMODE_PREAD | FMODE_PWRITE;
|
|
|
|
path_get(&f->f_path);
|
|
f->f_inode = inode;
|
|
f->f_mapping = inode->i_mapping;
|
|
|
|
if (unlikely(f->f_flags & O_PATH)) {
|
|
f->f_mode = FMODE_PATH;
|
|
f->f_op = &empty_fops;
|
|
return 0;
|
|
}
|
|
|
|
if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
|
|
error = get_write_access(inode);
|
|
if (unlikely(error))
|
|
goto cleanup_file;
|
|
error = __mnt_want_write(f->f_path.mnt);
|
|
if (unlikely(error)) {
|
|
put_write_access(inode);
|
|
goto cleanup_file;
|
|
}
|
|
f->f_mode |= FMODE_WRITER;
|
|
}
|
|
|
|
/* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
|
|
if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
|
|
f->f_mode |= FMODE_ATOMIC_POS;
|
|
|
|
f->f_op = fops_get(inode->i_fop);
|
|
if (unlikely(WARN_ON(!f->f_op))) {
|
|
error = -ENODEV;
|
|
goto cleanup_all;
|
|
}
|
|
|
|
error = security_file_open(f, cred);
|
|
if (error)
|
|
goto cleanup_all;
|
|
|
|
error = break_lease(locks_inode(f), f->f_flags);
|
|
if (error)
|
|
goto cleanup_all;
|
|
|
|
if (!open)
|
|
open = f->f_op->open;
|
|
if (open) {
|
|
error = open(inode, f);
|
|
if (error)
|
|
goto cleanup_all;
|
|
}
|
|
if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
|
|
i_readcount_inc(inode);
|
|
if ((f->f_mode & FMODE_READ) &&
|
|
likely(f->f_op->read || f->f_op->read_iter))
|
|
f->f_mode |= FMODE_CAN_READ;
|
|
if ((f->f_mode & FMODE_WRITE) &&
|
|
likely(f->f_op->write || f->f_op->write_iter))
|
|
f->f_mode |= FMODE_CAN_WRITE;
|
|
|
|
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
|
|
|
|
file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
|
|
|
|
return 0;
|
|
|
|
cleanup_all:
|
|
fops_put(f->f_op);
|
|
if (f->f_mode & FMODE_WRITER) {
|
|
put_write_access(inode);
|
|
__mnt_drop_write(f->f_path.mnt);
|
|
}
|
|
cleanup_file:
|
|
path_put(&f->f_path);
|
|
f->f_path.mnt = NULL;
|
|
f->f_path.dentry = NULL;
|
|
f->f_inode = NULL;
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* finish_open - finish opening a file
|
|
* @file: file pointer
|
|
* @dentry: pointer to dentry
|
|
* @open: open callback
|
|
* @opened: state of open
|
|
*
|
|
* This can be used to finish opening a file passed to i_op->atomic_open().
|
|
*
|
|
* If the open callback is set to NULL, then the standard f_op->open()
|
|
* filesystem callback is substituted.
|
|
*
|
|
* NB: the dentry reference is _not_ consumed. If, for example, the dentry is
|
|
* the return value of d_splice_alias(), then the caller needs to perform dput()
|
|
* on it after finish_open().
|
|
*
|
|
* On successful return @file is a fully instantiated open file. After this, if
|
|
* an error occurs in ->atomic_open(), it needs to clean up with fput().
|
|
*
|
|
* Returns zero on success or -errno if the open failed.
|
|
*/
|
|
int finish_open(struct file *file, struct dentry *dentry,
|
|
int (*open)(struct inode *, struct file *),
|
|
int *opened)
|
|
{
|
|
int error;
|
|
BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
|
|
|
|
file->f_path.dentry = dentry;
|
|
error = do_dentry_open(file, d_backing_inode(dentry), open,
|
|
current_cred());
|
|
if (!error)
|
|
*opened |= FILE_OPENED;
|
|
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL(finish_open);
|
|
|
|
/**
|
|
* finish_no_open - finish ->atomic_open() without opening the file
|
|
*
|
|
* @file: file pointer
|
|
* @dentry: dentry or NULL (as returned from ->lookup())
|
|
*
|
|
* This can be used to set the result of a successful lookup in ->atomic_open().
|
|
*
|
|
* NB: unlike finish_open() this function does consume the dentry reference and
|
|
* the caller need not dput() it.
|
|
*
|
|
* Returns "1" which must be the return value of ->atomic_open() after having
|
|
* called this function.
|
|
*/
|
|
int finish_no_open(struct file *file, struct dentry *dentry)
|
|
{
|
|
file->f_path.dentry = dentry;
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(finish_no_open);
|
|
|
|
char *file_path(struct file *filp, char *buf, int buflen)
|
|
{
|
|
return d_path(&filp->f_path, buf, buflen);
|
|
}
|
|
EXPORT_SYMBOL(file_path);
|
|
|
|
/**
|
|
* vfs_open - open the file at the given path
|
|
* @path: path to open
|
|
* @file: newly allocated file with f_flag initialized
|
|
* @cred: credentials to use
|
|
*/
|
|
int vfs_open(const struct path *path, struct file *file,
|
|
const struct cred *cred)
|
|
{
|
|
struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags);
|
|
|
|
if (IS_ERR(dentry))
|
|
return PTR_ERR(dentry);
|
|
|
|
file->f_path = *path;
|
|
return do_dentry_open(file, d_backing_inode(dentry), NULL, cred);
|
|
}
|
|
|
|
struct file *dentry_open(const struct path *path, int flags,
|
|
const struct cred *cred)
|
|
{
|
|
int error;
|
|
struct file *f;
|
|
|
|
validate_creds(cred);
|
|
|
|
/* We must always pass in a valid mount pointer. */
|
|
BUG_ON(!path->mnt);
|
|
|
|
f = get_empty_filp();
|
|
if (!IS_ERR(f)) {
|
|
f->f_flags = flags;
|
|
error = vfs_open(path, f, cred);
|
|
if (!error) {
|
|
/* from now on we need fput() to dispose of f */
|
|
error = open_check_o_direct(f);
|
|
if (error) {
|
|
fput(f);
|
|
f = ERR_PTR(error);
|
|
}
|
|
} else {
|
|
put_filp(f);
|
|
f = ERR_PTR(error);
|
|
}
|
|
}
|
|
return f;
|
|
}
|
|
EXPORT_SYMBOL(dentry_open);
|
|
|
|
static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
|
|
{
|
|
int lookup_flags = 0;
|
|
int acc_mode = ACC_MODE(flags);
|
|
|
|
if (flags & (O_CREAT | __O_TMPFILE))
|
|
op->mode = (mode & S_IALLUGO) | S_IFREG;
|
|
else
|
|
op->mode = 0;
|
|
|
|
/* Must never be set by userspace */
|
|
flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
|
|
|
|
/*
|
|
* O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
|
|
* check for O_DSYNC if the need any syncing at all we enforce it's
|
|
* always set instead of having to deal with possibly weird behaviour
|
|
* for malicious applications setting only __O_SYNC.
|
|
*/
|
|
if (flags & __O_SYNC)
|
|
flags |= O_DSYNC;
|
|
|
|
if (flags & __O_TMPFILE) {
|
|
if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
|
|
return -EINVAL;
|
|
if (!(acc_mode & MAY_WRITE))
|
|
return -EINVAL;
|
|
} else if (flags & O_PATH) {
|
|
/*
|
|
* If we have O_PATH in the open flag. Then we
|
|
* cannot have anything other than the below set of flags
|
|
*/
|
|
flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
|
|
acc_mode = 0;
|
|
}
|
|
|
|
op->open_flag = flags;
|
|
|
|
/* O_TRUNC implies we need access checks for write permissions */
|
|
if (flags & O_TRUNC)
|
|
acc_mode |= MAY_WRITE;
|
|
|
|
/* Allow the LSM permission hook to distinguish append
|
|
access from general write access. */
|
|
if (flags & O_APPEND)
|
|
acc_mode |= MAY_APPEND;
|
|
|
|
op->acc_mode = acc_mode;
|
|
|
|
op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
|
|
|
|
if (flags & O_CREAT) {
|
|
op->intent |= LOOKUP_CREATE;
|
|
if (flags & O_EXCL)
|
|
op->intent |= LOOKUP_EXCL;
|
|
}
|
|
|
|
if (flags & O_DIRECTORY)
|
|
lookup_flags |= LOOKUP_DIRECTORY;
|
|
if (!(flags & O_NOFOLLOW))
|
|
lookup_flags |= LOOKUP_FOLLOW;
|
|
op->lookup_flags = lookup_flags;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* file_open_name - open file and return file pointer
|
|
*
|
|
* @name: struct filename containing path to open
|
|
* @flags: open flags as per the open(2) second argument
|
|
* @mode: mode for the new file if O_CREAT is set, else ignored
|
|
*
|
|
* This is the helper to open a file from kernelspace if you really
|
|
* have to. But in generally you should not do this, so please move
|
|
* along, nothing to see here..
|
|
*/
|
|
struct file *file_open_name(struct filename *name, int flags, umode_t mode)
|
|
{
|
|
struct open_flags op;
|
|
int err = build_open_flags(flags, mode, &op);
|
|
return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
|
|
}
|
|
|
|
/**
|
|
* filp_open - open file and return file pointer
|
|
*
|
|
* @filename: path to open
|
|
* @flags: open flags as per the open(2) second argument
|
|
* @mode: mode for the new file if O_CREAT is set, else ignored
|
|
*
|
|
* This is the helper to open a file from kernelspace if you really
|
|
* have to. But in generally you should not do this, so please move
|
|
* along, nothing to see here..
|
|
*/
|
|
struct file *filp_open(const char *filename, int flags, umode_t mode)
|
|
{
|
|
struct filename *name = getname_kernel(filename);
|
|
struct file *file = ERR_CAST(name);
|
|
|
|
if (!IS_ERR(name)) {
|
|
file = file_open_name(name, flags, mode);
|
|
putname(name);
|
|
}
|
|
return file;
|
|
}
|
|
EXPORT_SYMBOL(filp_open);
|
|
|
|
struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
|
|
const char *filename, int flags, umode_t mode)
|
|
{
|
|
struct open_flags op;
|
|
int err = build_open_flags(flags, mode, &op);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
return do_file_open_root(dentry, mnt, filename, &op);
|
|
}
|
|
EXPORT_SYMBOL(file_open_root);
|
|
|
|
struct file *filp_clone_open(struct file *oldfile)
|
|
{
|
|
struct file *file;
|
|
int retval;
|
|
|
|
file = get_empty_filp();
|
|
if (IS_ERR(file))
|
|
return file;
|
|
|
|
file->f_flags = oldfile->f_flags;
|
|
retval = vfs_open(&oldfile->f_path, file, oldfile->f_cred);
|
|
if (retval) {
|
|
put_filp(file);
|
|
return ERR_PTR(retval);
|
|
}
|
|
|
|
return file;
|
|
}
|
|
EXPORT_SYMBOL(filp_clone_open);
|
|
|
|
long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
|
|
{
|
|
struct open_flags op;
|
|
int fd = build_open_flags(flags, mode, &op);
|
|
struct filename *tmp;
|
|
|
|
if (fd)
|
|
return fd;
|
|
|
|
tmp = getname(filename);
|
|
if (IS_ERR(tmp))
|
|
return PTR_ERR(tmp);
|
|
|
|
fd = get_unused_fd_flags(flags);
|
|
if (fd >= 0) {
|
|
struct file *f = do_filp_open(dfd, tmp, &op);
|
|
if (IS_ERR(f)) {
|
|
put_unused_fd(fd);
|
|
fd = PTR_ERR(f);
|
|
} else {
|
|
fsnotify_open(f);
|
|
fd_install(fd, f);
|
|
}
|
|
}
|
|
putname(tmp);
|
|
return fd;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
|
|
{
|
|
if (force_o_largefile())
|
|
flags |= O_LARGEFILE;
|
|
|
|
return do_sys_open(AT_FDCWD, filename, flags, mode);
|
|
}
|
|
|
|
SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
|
|
umode_t, mode)
|
|
{
|
|
if (force_o_largefile())
|
|
flags |= O_LARGEFILE;
|
|
|
|
return do_sys_open(dfd, filename, flags, mode);
|
|
}
|
|
|
|
#ifndef __alpha__
|
|
|
|
/*
|
|
* For backward compatibility? Maybe this should be moved
|
|
* into arch/i386 instead?
|
|
*/
|
|
SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
|
|
{
|
|
return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* "id" is the POSIX thread ID. We use the
|
|
* files pointer for this..
|
|
*/
|
|
int filp_close(struct file *filp, fl_owner_t id)
|
|
{
|
|
int retval = 0;
|
|
|
|
if (!file_count(filp)) {
|
|
printk(KERN_ERR "VFS: Close: file count is 0\n");
|
|
return 0;
|
|
}
|
|
|
|
if (filp->f_op->flush)
|
|
retval = filp->f_op->flush(filp, id);
|
|
|
|
if (likely(!(filp->f_mode & FMODE_PATH))) {
|
|
dnotify_flush(filp, id);
|
|
locks_remove_posix(filp, id);
|
|
}
|
|
fput(filp);
|
|
return retval;
|
|
}
|
|
|
|
EXPORT_SYMBOL(filp_close);
|
|
|
|
/*
|
|
* Careful here! We test whether the file pointer is NULL before
|
|
* releasing the fd. This ensures that one clone task can't release
|
|
* an fd while another clone is opening it.
|
|
*/
|
|
SYSCALL_DEFINE1(close, unsigned int, fd)
|
|
{
|
|
int retval = __close_fd(current->files, fd);
|
|
|
|
/* can't restart close syscall because file table entry was cleared */
|
|
if (unlikely(retval == -ERESTARTSYS ||
|
|
retval == -ERESTARTNOINTR ||
|
|
retval == -ERESTARTNOHAND ||
|
|
retval == -ERESTART_RESTARTBLOCK))
|
|
retval = -EINTR;
|
|
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL(sys_close);
|
|
|
|
/*
|
|
* This routine simulates a hangup on the tty, to arrange that users
|
|
* are given clean terminals at login time.
|
|
*/
|
|
SYSCALL_DEFINE0(vhangup)
|
|
{
|
|
if (capable(CAP_SYS_TTY_CONFIG)) {
|
|
tty_vhangup_self();
|
|
return 0;
|
|
}
|
|
return -EPERM;
|
|
}
|
|
|
|
/*
|
|
* Called when an inode is about to be open.
|
|
* We use this to disallow opening large files on 32bit systems if
|
|
* the caller didn't specify O_LARGEFILE. On 64bit systems we force
|
|
* on this flag in sys_open.
|
|
*/
|
|
int generic_file_open(struct inode * inode, struct file * filp)
|
|
{
|
|
if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
|
|
return -EOVERFLOW;
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(generic_file_open);
|
|
|
|
/*
|
|
* This is used by subsystems that don't want seekable
|
|
* file descriptors. The function is not supposed to ever fail, the only
|
|
* reason it returns an 'int' and not 'void' is so that it can be plugged
|
|
* directly into file_operations structure.
|
|
*/
|
|
int nonseekable_open(struct inode *inode, struct file *filp)
|
|
{
|
|
filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(nonseekable_open);
|