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* ovl: store real inode pointer in ->i_privateMiklos Szeredi2016-07-295-37/+40
| | | | | | | | | | | | | | | | To get from overlay inode to real inode we currently use 'struct ovl_entry', which has lifetime connected to overlay dentry. This is okay, since each overlay dentry had a new overlay inode allocated. Following patch will break that assumption, so need to leave out ovl_entry. This patch stores the real inode directly in i_private, with the lowest bit used to indicate whether the inode is upper or lower. Lifetime rules remain, using ovl_inode_real() must only be done while caller holds ref on overlay dentry (and hence on real dentry), or within RCU protected regions. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: permission: return ECHILD instead of ENOENTMiklos Szeredi2016-07-291-1/+1
| | | | | | The error is due to RCU and is temporary. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: update atime on upperMiklos Szeredi2016-07-294-5/+37
| | | | | | | | | | | | | | | | | Fix atime update logic in overlayfs. This patch adds an i_op->update_time() handler to overlayfs inodes. This forwards atime updates to the upper layer only. No atime updates are done on lower layers. Remove implicit atime updates to underlying files and directories with O_NOATIME. Remove explicit atime update in ovl_readlink(). Clear atime related mnt flags from cloned upper mount. This means atime updates are controlled purely by overlayfs mount options. Reported-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix sgid on directoryMiklos Szeredi2016-07-291-4/+27
| | | | | | | | | | | | | When creating directory in workdir, the group/sgid inheritance from the parent dir was omitted completely. Fix this by calling inode_init_owner() on overlay inode and using the resulting uid/gid/mode to create the file. Unfortunately the sgid bit can be stripped off due to umask, so need to reset the mode in this case in workdir before moving the directory in place. Reported-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: simplify permission checkingMiklos Szeredi2016-07-293-53/+1
| | | | | | | | | | | | | | | | | | The fact that we always do permission checking on the overlay inode and clear MAY_WRITE for checking access to the lower inode allows cruft to be removed from ovl_permission(). 1) "default_permissions" option effectively did generic_permission() on the overlay inode with i_mode, i_uid and i_gid updated from underlying filesystem. This is what we do by default now. It did the update using vfs_getattr() but that's only needed if the underlying filesystem can change (which is not allowed). We may later introduce a "paranoia_mode" that verifies that mode/uid/gid are not changed. 2) splitting out the IS_RDONLY() check from inode_permission() also becomes unnecessary once we remove the MAY_WRITE from the lower inode check. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: do not require mounter to have MAY_WRITE on lowerVivek Goyal2016-07-291-0/+2
| | | | | | | | | | | | | | | | | | | | | | Now we have two levels of checks in ovl_permission(). overlay inode is checked with the creds of task while underlying inode is checked with the creds of mounter. Looks like mounter does not have to have WRITE access to files on lower/. So remove the MAY_WRITE from access mask for checks on underlying lower inode. This means task should still have the MAY_WRITE permission on lower inode and mounter is not required to have MAY_WRITE. It also solves the problem of read only NFS mounts being used as lower. If __inode_permission(lower_inode, MAY_WRITE) is called on read only NFS, it fails. By resetting MAY_WRITE, check succeeds and case of read only NFS shold work with overlay without having to specify any special mount options (default permission). Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: do operations on underlying file system in mounter's contextVivek Goyal2016-07-292-37/+72
| | | | | | | | | | | | Given we are now doing checks both on overlay inode as well underlying inode, we should be able to do checks and operations on underlying file system using mounter's context. So modify all operations to do checks/operations on underlying dentry/inode in the context of mounter. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: modify ovl_permission() to do checks on two inodesVivek Goyal2016-07-291-4/+14
| | | | | | | | | | | | Right now ovl_permission() calls __inode_permission(realinode), to do permission checks on real inode and no checks are done on overlay inode. Modify it to do checks both on overlay inode as well as underlying inode. Checks on overlay inode will be done with the creds of calling task while checks on underlying inode will be done with the creds of mounter. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: define ->get_acl() for overlay inodesVivek Goyal2016-07-294-0/+28
| | | | | | | | | | Now we are planning to do DAC permission checks on overlay inode itself. And to make it work, we will need to make sure we can get acls from underlying inode. So define ->get_acl() for overlay inodes and this in turn calls into underlying filesystem to get acls, if any. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: move some common code in a functionVivek Goyal2016-07-291-8/+12
| | | | | | | | | ovl_create_upper() and ovl_create_over_whiteout() seem to be sharing some common code which can be moved into a separate function. No functionality change. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: store ovl_entry in inode->i_private for all inodesAndreas Gruenbacher2016-07-291-37/+11
| | | | | | | | | Previously this was only done for directory inodes. Doing so for all inodes makes for a nice cleanup in ovl_permission at zero cost. Inodes are not shared for hard links on the overlay, so this works fine. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: use generic_delete_inodeMiklos Szeredi2016-07-291-0/+1
| | | | | | No point in keeping overlay inodes around since they will never be reused. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: check mounter creds on underlying lookupMiklos Szeredi2016-07-291-4/+9
| | | | | | | | | | | | | | | | The hash salting changes meant that we can no longer reuse the hash in the overlay dentry to look up the underlying dentry. Instead of lookup_hash(), use lookup_one_len_unlocked() and swith to mounter's creds (like we do for all other operations later in the series). Now the lookup_hash() export introduced in 4.6 by 3c9fe8cdff1b ("vfs: add lookup_hash() helper") is unused and can possibly be removed; its usefulness negated by the hash salting and the idea that mounter's creds should be used on operations on underlying filesystems. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 8387ff2577eb ("vfs: make the string hashes salt the hash")
* Merge branch 'd_real' into overlayfs-nextMiklos Szeredi2016-07-273-28/+25
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| * vfs: merge .d_select_inode() into .d_real()Miklos Szeredi2016-06-303-28/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The two methods essentially do the same: find the real dentry/inode belonging to an overlay dentry. The difference is in the usage: vfs_open() uses ->d_select_inode() and expects the function to perform copy-up if necessary based on the open flags argument. file_dentry() uses ->d_real() passing in the overlay dentry as well as the underlying inode. vfs_rename() uses ->d_select_inode() but passes zero flags. ->d_real() with a zero inode would have worked just as well here. This patch merges the functionality of ->d_select_inode() into ->d_real() by adding an 'open_flags' argument to the latter. [Al Viro] Make the signature of d_real() match that of ->d_real() again. And constify the inode argument, while we are at it. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | ovl: verify upper dentry in ovl_remove_and_whiteout()Maxim Patlasov2016-07-221-30/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The upper dentry may become stale before we call ovl_lock_rename_workdir. For example, someone could (mistakenly or maliciously) manually unlink(2) it directly from upperdir. To ensure it is not stale, let's lookup it after ovl_lock_rename_workdir and and check if it matches the upper dentry. Essentially, it is the same problem and similar solution as in commit 11f3710417d0 ("ovl: verify upper dentry before unlink and rename"). Signed-off-by: Maxim Patlasov <mpatlasov@virtuozzo.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>
* | ovl: Copy up underlying inode's ->i_mode to overlay inodeVivek Goyal2016-07-042-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Right now when a new overlay inode is created, we initialize overlay inode's ->i_mode from underlying inode ->i_mode but we retain only file type bits (S_IFMT) and discard permission bits. This patch changes it and retains permission bits too. This should allow overlay to do permission checks on overlay inode itself in task context. [SzM] It also fixes clearing suid/sgid bits on write. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reported-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Cc: <stable@vger.kernel.org>
* | ovl: handle ATTR_KILL*Miklos Szeredi2016-07-041-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before 4bacc9c9234c ("overlayfs: Make f_path...") file->f_path pointed to the underlying file, hence suid/sgid removal on write worked fine. After that patch file->f_path pointed to the overlay file, and the file mode bits weren't copied to overlay_inode->i_mode. So the suid/sgid removal simply stopped working. The fix is to copy the mode bits, but then ovl_setattr() needs to clear ATTR_MODE to avoid the BUG() in notify_change(). So do this first, then in the next patch copy the mode. Reported-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Cc: <stable@vger.kernel.org>
* | ovl: warn instead of error if d_type is not supportedVivek Goyal2016-07-031-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | overlay needs underlying fs to support d_type. Recently I put in a patch in to detect this condition and started failing mount if underlying fs did not support d_type. But this breaks existing configurations over kernel upgrade. Those who are running docker (partially broken configuration) with xfs not supporting d_type, are surprised that after kernel upgrade docker does not run anymore. https://github.com/docker/docker/issues/22937#issuecomment-229881315 So instead of erroring out, detect broken configuration and warn about it. This should allow existing docker setups to continue working after kernel upgrade. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 45aebeaf4f67 ("ovl: Ensure upper filesystem supports d_type") Cc: <stable@vger.kernel.org> 4.6
* | ovl: get_write_access() in truncateMiklos Szeredi2016-06-291-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When truncating a file we should check write access on the underlying inode. And we should do so on the lower file as well (before copy-up) for consistency. Original patch and test case by Aihua Zhang. - - >o >o - - test.c - - >o >o - - #include <stdio.h> #include <errno.h> #include <unistd.h> int main(int argc, char *argv[]) { int ret; ret = truncate(argv[0], 4096); if (ret != -1) { fprintf(stderr, "truncate(argv[0]) should have failed\n"); return 1; } if (errno != ETXTBSY) { perror("truncate(argv[0])"); return 1; } return 0; } - - >o >o - - >o >o - - >o >o - - Reported-by: Aihua Zhang <zhangaihua1@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>
* | ovl: fix dentry leak for default_permissionsMiklos Szeredi2016-06-291-3/+5
|/ | | | | | | | | | When using the 'default_permissions' mount option, ovl_permission() on non-directories was missing a dput(alias), resulting in "BUG Dentry still in use". Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 8d3095f4ad47 ("ovl: default permissions") Cc: <stable@vger.kernel.org> # v4.5+
* ovl: fix uid/gid when creating over whiteoutMiklos Szeredi2016-06-151-2/+11
| | | | | | | | | | | | | | | | | | | | Fix a regression when creating a file over a whiteout. The new file/directory needs to use the current fsuid/fsgid, not the ones from the mounter's credentials. The refcounting is a bit tricky: prepare_creds() sets an original refcount, override_creds() gets one more, which revert_cred() drops. So 1) we need to expicitly put the mounter's credentials when overriding with the updated one 2) we need to put the original ref to the updated creds (and this can safely be done before revert_creds(), since we'll still have the ref from override_creds()). Reported-by: Stephen Smalley <sds@tycho.nsa.gov> Fixes: 3fe6e52f0626 ("ovl: override creds with the ones from the superblock mounter") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: xattr filter fixMiklos Szeredi2016-06-061-20/+6
| | | | | | | | | | | | | | | | | | | | a) ovl_need_xattr_filter() is wrong, we can have multiple lower layers overlaid, all of which (except the lowest one) honouring the "trusted.overlay.opaque" xattr. So need to filter everything except the bottom and the pure-upper layer. b) we no longer can assume that inode is attached to dentry in get/setxattr. This patch unconditionally filters private xattrs to fix both of the above. Performance impact for get/removexattrs is likely in the noise. For listxattrs it might be measurable in pathological cases, but I very much hope nobody cares. If they do, we'll fix it then. Reported-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: b96809173e94 ("security_d_instantiate(): move to the point prior to attaching dentry to inode")
* Merge branch 'for-linus' of ↵Linus Torvalds2016-05-273-7/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fixes from Al Viro: "Followups to the parallel lookup work: - update docs - restore killability of the places that used to take ->i_mutex killably now that we have down_write_killable() merged - Additionally, it turns out that I missed a prerequisite for security_d_instantiate() stuff - ->getxattr() wasn't the only thing that could be called before dentry is attached to inode; with smack we needed the same treatment applied to ->setxattr() as well" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch ->setxattr() to passing dentry and inode separately switch xattr_handler->set() to passing dentry and inode separately restore killability of old mutex_lock_killable(&inode->i_mutex) users add down_write_killable_nested() update D/f/directory-locking
| * switch ->setxattr() to passing dentry and inode separatelyAl Viro2016-05-272-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | smack ->d_instantiate() uses ->setxattr(), so to be able to call it before we'd hashed the new dentry and attached it to inode, we need ->setxattr() instances getting the inode as an explicit argument rather than obtaining it from dentry. Similar change for ->getxattr() had been done in commit ce23e64. Unlike ->getxattr() (which is used by both selinux and smack instances of ->d_instantiate()) ->setxattr() is used only by smack one and unfortunately it got missed back then. Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * restore killability of old mutex_lock_killable(&inode->i_mutex) usersAl Viro2016-05-261-3/+1
| | | | | | | | | | | | The ones that are taking it exclusive, that is... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'overlayfs-linus' of ↵Linus Torvalds2016-05-275-107/+38
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs update from Miklos Szeredi: "The meat of this is a change to use the mounter's credentials for operations that require elevated privileges (such as whiteout creation). This fixes behavior under user namespaces as well as being a nice cleanup" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: Do d_type check only if work dir creation was successful ovl: update documentation ovl: override creds with the ones from the superblock mounter
| * ovl: Do d_type check only if work dir creation was successfulVivek Goyal2016-05-271-8/+11
| | | | | | | | | | | | | | | | | | | | | | | | d_type check requires successful creation of workdir as iterates through work dir and expects work dir to be present in it. If that's not the case, this check will always return d_type not supported even if underlying filesystem might be supporting it. So don't do this check if work dir creation failed in previous step. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: override creds with the ones from the superblock mounterAntonio Murdaca2016-05-275-99/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In user namespace the whiteout creation fails with -EPERM because the current process isn't capable(CAP_SYS_ADMIN) when setting xattr. A simple reproducer: $ mkdir upper lower work merged lower/dir $ sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merged $ unshare -m -p -f -U -r bash Now as root in the user namespace: \# touch merged/dir/{1,2,3} # this will force a copy up of lower/dir \# rm -fR merged/* This ends up failing with -EPERM after the files in dir has been correctly deleted: unlinkat(4, "2", 0) = 0 unlinkat(4, "1", 0) = 0 unlinkat(4, "3", 0) = 0 close(4) = 0 unlinkat(AT_FDCWD, "merged/dir", AT_REMOVEDIR) = -1 EPERM (Operation not permitted) Interestingly, if you don't place files in merged/dir you can remove it, meaning if upper/dir does not exist, creating the char device file works properly in that same location. This patch uses ovl_sb_creator_cred() to get the cred struct from the superblock mounter and override the old cred with these new ones so that the whiteout creation is possible because overlay is wrong in assuming that the creds it will get with prepare_creds will be in the initial user namespace. The old cap_raise game is removed in favor of just overriding the old cred struct. This patch also drops from ovl_copy_up_one() the following two lines: override_cred->fsuid = stat->uid; override_cred->fsgid = stat->gid; This is because the correct uid and gid are taken directly with the stat struct and correctly set with ovl_set_attr(). Signed-off-by: Antonio Murdaca <runcom@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | Merge branch 'ovl-fixes' into for-linusAl Viro2016-05-171-1/+1
|\ \ | |/ | | | | | | | | Backmerge to resolve a conflict in ovl_lookup_real(); "ovl_lookup_real(): use lookup_one_len_unlocked()" instead, but it was too late in the cycle to rebase.
| * ovl: ignore permissions on underlying lookupMiklos Szeredi2016-05-101-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generally permission checking is not necessary when overlayfs looks up a dentry on one of the underlying layers, since search permission on base directory was already checked in ovl_permission(). More specifically using lookup_one_len() causes a problem when the lower directory lacks search permission for a specific user while the upper directory does have search permission. Since lookups are cached, this causes inconsistency in behavior: success depends on who did the first lookup. So instead use lookup_hash() which doesn't do the permission check. Reported-by: Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | parallel lookups: actual switch to rwsemAl Viro2016-05-021-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | ta-da! The main issue is the lack of down_write_killable(), so the places like readdir.c switched to plain inode_lock(); once killable variants of rwsem primitives appear, that'll be dealt with. lockdep side also might need more work Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | ovl_lookup_real(): use lookup_one_len_unlocked()Al Viro2016-05-021-3/+1
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge getxattr prototype change into work.lookupsAl Viro2016-05-023-5/+5
|\ \ | |/ |/| | | The rest of work.xattr stuff isn't needed for this branch
| * ->getxattr(): pass dentry and inode as separate argumentsAl Viro2016-04-113-5/+5
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fs: add file_dentry()Miklos Szeredi2016-03-261-0/+33
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay"). Regular files opened on overlayfs will result in the file being opened on the underlying filesystem, while f_path points to the overlayfs mount/dentry. This confuses filesystems which get the dentry from struct file and assume it's theirs. Add a new helper, file_dentry() [*], to get the filesystem's own dentry from the file. This checks file->f_path.dentry->d_flags against DCACHE_OP_REAL, and returns file->f_path.dentry if DCACHE_OP_REAL is not set (this is the common, non-overlayfs case). In the uncommon case it will call into overlayfs's ->d_real() to get the underlying dentry, matching file_inode(file). The reason we need to check against the inode is that if the file is copied up while being open, d_real() would return the upper dentry, while the open file comes from the lower dentry. [*] If possible, it's better simply to use file_inode() instead. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: <stable@vger.kernel.org> # v4.2 Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Daniel Axtens <dja@axtens.net>
* ovl: cleanup unused var in rename2Miklos Szeredi2016-03-211-2/+0
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: rename is_merge to is_lowestMiklos Szeredi2016-03-211-8/+8
| | | | | | | | | | | The 'is_merge' is an historical naming from when only a single lower layer could exist. With the introduction of multiple lower layers the meaning of this flag was changed to mean only the "lowest layer" (while all lower layers were being merged). So now 'is_merge' is inaccurate and hence renaming to 'is_lowest' Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fixed coding style warningSohom Bhattacharjee2016-03-211-0/+1
| | | | | | | This patch fixes a newline warning found by the checkpatch.pl tool Signed-off-by: Sohom-Bhattacharjee <soham.bhattacharjee15@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Ensure upper filesystem supports d_typeVivek Goyal2016-03-213-0/+53
| | | | | | | | | | | | | | | | | In some instances xfs has been created with ftype=0 and there if a file on lower fs is removed, overlay leaves a whiteout in upper fs but that whiteout does not get filtered out and is visible to overlayfs users. And reason it does not get filtered out because upper filesystem does not report file type of whiteout as DT_CHR during iterate_dir(). So it seems to be a requirement that upper filesystem support d_type for overlayfs to work properly. Do this check during mount and fail if d_type is not supported. Suggested-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Warn on copy up if a process has a R/O fd open to the lower fileDavid Howells2016-03-211-0/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Print a warning when overlayfs copies up a file if the process that triggered the copy up has a R/O fd open to the lower file being copied up. This can help catch applications that do things like the following: fd1 = open("foo", O_RDONLY); fd2 = open("foo", O_RDWR); where they expect fd1 and fd2 to refer to the same file - which will no longer be the case post-copy up. With this patch, the following commands: bash 5</mnt/a/foo128 6<>/mnt/a/foo128 assuming /mnt/a/foo128 to be an un-copied up file on an overlay will produce the following warning in the kernel log: overlayfs: Copying up foo129, but open R/O on fd 5 which will cease to be coherent [pid=3818 bash] This is enabled by setting: /sys/module/overlay/parameters/check_copy_up to 1. The warnings are ratelimited and are also limited to one warning per file - assuming the copy up completes in each case. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: honor flag MS_SILENT at mountKonstantin Khlebnikov2016-03-211-1/+2
| | | | | | | | | | | This patch hides error about missing lowerdir if MS_SILENT is set. We use mount(NULL, "/", "overlay", MS_SILENT, NULL) for testing support of overlayfs: syscall returns -ENODEV if it's not supported. Otherwise kernel automatically loads module and returns -EINVAL because lowerdir is missing. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: verify upper dentry before unlink and renameMiklos Szeredi2016-03-211-21/+38
| | | | | | | | | | | | | Unlink and rename in overlayfs checked the upper dentry for staleness by verifying upper->d_parent against upperdir. However the dentry can go stale also by being unhashed, for example. Expand the verification to actually look up the name again (under parent lock) and check if it matches the upper dentry. This matches what the VFS does before passing the dentry to filesytem's unlink/rename methods, which excludes any inconsistency caused by overlayfs. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: copy new uid/gid into overlayfs runtime inodeKonstantin Khlebnikov2016-03-031-0/+2
| | | | | | | | | | Overlayfs must update uid/gid after chown, otherwise functions like inode_owner_or_capable() will check user against stale uid. Catched by xfstests generic/087, it chowns file and calls utimes. Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
* ovl: ignore lower entries when checking purity of non-directory entriesKonstantin Khlebnikov2016-03-032-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After rename file dentry still holds reference to lower dentry from previous location. This doesn't matter for data access because data comes from upper dentry. But this stale lower dentry taints dentry at new location and turns it into non-pure upper. Such file leaves visible whiteout entry after remove in directory which shouldn't have whiteouts at all. Overlayfs already tracks pureness of file location in oe->opaque. This patch just uses that for detecting actual path type. Comment from Vivek Goyal's patch: Here are the details of the problem. Do following. $ mkdir upper lower work merged upper/dir/ $ touch lower/test $ sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir= work merged $ mv merged/test merged/dir/ $ rm merged/dir/test $ ls -l merged/dir/ /usr/bin/ls: cannot access merged/dir/test: No such file or directory total 0 c????????? ? ? ? ? ? test Basic problem seems to be that once a file has been unlinked, a whiteout has been left behind which was not needed and hence it becomes visible. Whiteout is visible because parent dir is of not type MERGE, hence od->is_real is set during ovl_dir_open(). And that means ovl_iterate() passes on iterate handling directly to underlying fs. Underlying fs does not know/filter whiteouts so it becomes visible to user. Why did we leave a whiteout to begin with when we should not have. ovl_do_remove() checks for OVL_TYPE_PURE_UPPER() and does not leave whiteout if file is pure upper. In this case file is not found to be pure upper hence whiteout is left. So why file was not PURE_UPPER in this case? I think because dentry is still carrying some leftover state which was valid before rename. For example, od->numlower was set to 1 as it was a lower file. After rename, this state is not valid anymore as there is no such file in lower. Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Reported-by: Viktor Stanchev <me@viktorstanchev.com> Suggested-by: Vivek Goyal <vgoyal@redhat.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=109611 Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
* ovl: fix getcwd() failure after unsuccessful rmdirRui Wang2016-03-031-1/+2
| | | | | | | | | | | | | ovl_remove_upper() should do d_drop() only after it successfully removes the dir, otherwise a subsequent getcwd() system call will fail, breaking userspace programs. This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491 Signed-off-by: Rui Wang <rui.y.wang@intel.com> Reviewed-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
* ovl: fix working on distributed fs as lower layerKonstantin Khlebnikov2016-03-031-0/+1
| | | | | | | | | | | | This adds missing .d_select_inode into alternative dentry_operations. Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com> Fixes: 7c03b5d45b8e ("ovl: allow distributed fs as lower layer") Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay") Reviewed-by: Nikolay Borisov <kernel@kyup.com> Tested-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org> # 4.2+
* wrappers for ->i_mutex accessAl Viro2016-01-225-27/+27
| | | | | | | | | | | parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2016-01-211-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge third patch-bomb from Andrew Morton: "I'm pretty much done for -rc1 now: - the rest of MM, basically - lib/ updates - checkpatch, epoll, hfs, fatfs, ptrace, coredump, exit - cpu_mask simplifications - kexec, rapidio, MAINTAINERS etc, etc. - more dma-mapping cleanups/simplifications from hch" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (109 commits) MAINTAINERS: add/fix git URLs for various subsystems mm: memcontrol: add "sock" to cgroup2 memory.stat mm: memcontrol: basic memory statistics in cgroup2 memory controller mm: memcontrol: do not uncharge old page in page cache replacement Documentation: cgroup: add memory.swap.{current,max} description mm: free swap cache aggressively if memcg swap is full mm: vmscan: do not scan anon pages if memcg swap limit is hit swap.h: move memcg related stuff to the end of the file mm: memcontrol: replace mem_cgroup_lruvec_online with mem_cgroup_online mm: vmscan: pass memcg to get_scan_count() mm: memcontrol: charge swap to cgroup2 mm: memcontrol: clean up alloc, online, offline, free functions mm: memcontrol: flatten struct cg_proto mm: memcontrol: rein in the CONFIG space madness net: drop tcp_memcontrol.c mm: memcontrol: introduce CONFIG_MEMCG_LEGACY_KMEM mm: memcontrol: allow to disable kmem accounting for cgroup2 mm: memcontrol: account "kmem" consumers in cgroup2 memory controller mm: memcontrol: move kmem accounting code to CONFIG_MEMCG mm: memcontrol: separate kmem code from legacy tcp accounting code ...
| * fs/overlayfs/super.c needs pagemap.hAndrew Morton2016-01-201-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | i386 allmodconfig: In file included from fs/overlayfs/super.c:10:0: fs/overlayfs/super.c: In function 'ovl_fill_super': include/linux/fs.h:898:36: error: 'PAGE_CACHE_SIZE' undeclared (first use in this function) #define MAX_LFS_FILESIZE (((loff_t)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) ^ fs/overlayfs/super.c:939:19: note: in expansion of macro 'MAX_LFS_FILESIZE' sb->s_maxbytes = MAX_LFS_FILESIZE; ^ include/linux/fs.h:898:36: note: each undeclared identifier is reported only once for each function it appears in #define MAX_LFS_FILESIZE (((loff_t)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) ^ fs/overlayfs/super.c:939:19: note: in expansion of macro 'MAX_LFS_FILESIZE' sb->s_maxbytes = MAX_LFS_FILESIZE; ^ Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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