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2015-09-05fs: create and use seq_show_option for escapingKees Cook1-3/+3
Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Jan Kara <jack@suse.com> Acked-by: Paul Moore <paul@paul-moore.com> Cc: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-12fix a braino in ovl_d_select_inode()Al Viro1-0/+3
when opening a directory we want the overlayfs inode, not one from the topmost layer. Reported-By: Andrey Jr. Melnikov <temnota.am@gmail.com> Tested-By: Andrey Jr. Melnikov <temnota.am@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-07-05Merge branch 'for-linus' of ↵Linus Torvalds3-15/+9
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-07-02Merge branch 'overlayfs-next' of ↵Linus Torvalds2-51/+139
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This relaxes the requirements on the lower layer filesystem: now ones that implement .d_revalidate, such as NFS, can be used. Upper layer filesystems still has the "no .d_revalidate" requirement. Also a bad interaction with jffs2 locking has been fixed" * 'overlayfs-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: lookup whiteouts outside iterate_dir() ovl: allow distributed fs as lower layer ovl: don't traverse automount points
2015-06-22Merge branch 'for-linus-1' of ↵Linus Torvalds1-17/+18
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "In this pile: pathname resolution rewrite. - recursion in link_path_walk() is gone. - nesting limits on symlinks are gone (the only limit remaining is that the total amount of symlinks is no more than 40, no matter how nested). - "fast" (inline) symlinks are handled without leaving rcuwalk mode. - stack footprint (independent of the nesting) is below kilobyte now, about on par with what it used to be with one level of nested symlinks and ~2.8 times lower than it used to be in the worst case. - struct nameidata is entirely private to fs/namei.c now (not even opaque pointers are being passed around). - ->follow_link() and ->put_link() calling conventions had been changed; all in-tree filesystems converted, out-of-tree should be able to follow reasonably easily. For out-of-tree conversions, see Documentation/filesystems/porting for details (and in-tree filesystems for examples of conversion). That has sat in -next since mid-May, seems to survive all testing without regressions and merges clean with v4.1" * 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (131 commits) turn user_{path_at,path,lpath,path_dir}() into static inlines namei: move saved_nd pointer into struct nameidata inline user_path_create() inline user_path_parent() namei: trim do_last() arguments namei: stash dfd and name into nameidata namei: fold path_cleanup() into terminate_walk() namei: saner calling conventions for filename_parentat() namei: saner calling conventions for filename_create() namei: shift nameidata down into filename_parentat() namei: make filename_lookup() reject ERR_PTR() passed as name namei: shift nameidata inside filename_lookup() namei: move putname() call into filename_lookup() namei: pass the struct path to store the result down into path_lookupat() namei: uninline set_root{,_rcu}() namei: be careful with mountpoint crossings in follow_dotdot_rcu() Documentation: remove outdated information from automount-support.txt get rid of assorted nameidata-related debris lustre: kill unused helper lustre: kill unused macro (LOOKUP_CONTINUE) ...
2015-06-22ovl: lookup whiteouts outside iterate_dir()Miklos Szeredi1-28/+49
If jffs2 can deadlock on overlayfs readdir because it takes the same lock on ->iterate() as in ->lookup(). Fix by moving whiteout checking outside iterate_dir(). Optimized by collecting potential whiteouts (DT_CHR) in a temporary list and if non-empty iterating throug these and checking for a 0/0 chardev. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Fixes: 49c21e1cacd7 ("ovl: check whiteout while reading directory") Reported-by: Roman Yeryomin <leroi.lists@gmail.com>
2015-06-22ovl: allow distributed fs as lower layerMiklos Szeredi1-25/+88
Allow filesystems with .d_revalidate as lower layer(s), but not as upper layer. For local filesystems the rule was that modifications on the layers directly while being part of the overlay results in undefined behavior. This can easily be extended to distributed filesystems: we assume the tree used as lower layer is static, which means ->d_revalidate() should always return "1". If that is not the case, return -ESTALE, don't try to work around the modification. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-06-22ovl: don't traverse automount pointsMiklos Szeredi1-2/+6
NFS and other distributed filesystems may place automount points in the tree. Previoulsy overlayfs refused to mount such filesystems types (based on the existence of the .d_automount callback), even if the actual export didn't have any automount points. It cannot be determined in advance whether the filesystem has automount points or not. The solution is to allow fs with .d_automount but refuse to traverse any automount points encountered. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-06-19overlayfs: Make f_path always point to the overlay and f_inode to the underlayDavid Howells3-8/+8
Make file->f_path always point to the overlay dentry so that the path in /proc/pid/fd is correct and to ensure that label-based LSMs have access to the overlay as well as the underlay (path-based LSMs probably don't need it). Using my union testsuite to set things up, before the patch I see: [root@andromeda union-testsuite]# bash 5</mnt/a/foo107 [root@andromeda union-testsuite]# ls -l /proc/$$/fd/ ... lr-x------. 1 root root 64 Jun 5 14:38 5 -> /a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 13381 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 13381 Links: 1 ... After the patch: [root@andromeda union-testsuite]# bash 5</mnt/a/foo107 [root@andromeda union-testsuite]# ls -l /proc/$$/fd/ ... lr-x------. 1 root root 64 Jun 5 14:22 5 -> /mnt/a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 40346 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 40346 Links: 1 ... Note the change in where /proc/$$/fd/5 points to in the ls command. It was pointing to /a/foo107 (which doesn't exist) and now points to /mnt/a/foo107 (which is correct). The inode accessed, however, is the lower layer. The union layer is on device 25h/37d and the upper layer on 24h/36d. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-06-19overlay: Call ovl_drop_write() earlier in ovl_dentry_open()David Howells1-10/+4
Call ovl_drop_write() earlier in ovl_dentry_open() before we call vfs_open() as we've done the copy up for which we needed the freeze-write lock by that point. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-19ovl: mount read-only if workdir can't be createdMiklos Szeredi3-5/+17
OpenWRT folks reported that overlayfs fails to mount if upper fs is full, because workdir can't be created. Wordir creation can fail for various other reasons too. There's no reason that the mount itself should fail, overlayfs can work fine without a workdir, as long as the overlay isn't modified. So mount it read-only and don't allow remounting read-write. Add a couple of WARN_ON()s for the impossible case of workdir being used despite being read-only. Reported-by: Bastian Bittorf <bittorf@bluebottle.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: <stable@vger.kernel.org> # v3.18+
2015-05-14ovl: don't remove non-empty opaque directoryMiklos Szeredi1-5/+19
When removing an opaque directory we can't just call rmdir() to check for emptiness, because the directory will need to be replaced with a whiteout. The replacement is done with RENAME_EXCHANGE, which doesn't check emptiness. Solution is just to check emptiness by reading the directory. In the future we could add a new rename flag to check for emptiness even for RENAME_EXCHANGE to optimize this case. Reported-by: Vincent Batts <vbatts@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: Jordi Pujol Palomer <jordipujolp@gmail.com> Fixes: 263b4a0fee43 ("ovl: dont replace opaque dir") Cc: <stable@vger.kernel.org> # v4.0+
2015-05-11switch ->put_link() from dentry to inodeAl Viro1-2/+2
only one instance looks at that argument at all; that sole exception wants inode rather than dentry. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11don't pass nameidata to ->follow_link()Al Viro1-2/+2
its only use is getting passed to nd_jump_link(), which can obtain it from current->nameidata Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11new ->follow_link() and ->put_link() calling conventionsAl Viro1-8/+10
a) instead of storing the symlink body (via nd_set_link()) and returning an opaque pointer later passed to ->put_link(), ->follow_link() _stores_ that opaque pointer (into void * passed by address by caller) and returns the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic symlinks) and pointer to symlink body for normal symlinks. Stored pointer is ignored in all cases except the last one. Storing NULL for opaque pointer (or not storing it at all) means no call of ->put_link(). b) the body used to be passed to ->put_link() implicitly (via nameidata). Now only the opaque pointer is. In the cases when we used the symlink body to free stuff, ->follow_link() now should store it as opaque pointer in addition to returning it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11ovl: rearrange ovl_follow_link to it doesn't need to call ->put_linkNeilBrown1-13/+12
ovl_follow_link current calls ->put_link on an error path. However ->put_link is about to change in a way that it will be impossible to call it from ovl_follow_link. So rearrange the code to avoid the need for that error path. Specifically: move the kmalloc() call before the ->follow_link() call to the subordinate filesystem. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-03-18ovl: upper fs should not be R/Ohujianyang1-5/+19
After importing multi-lower layer support, users could mount a r/o partition as the left most lowerdir instead of using it as upperdir. And a r/o upperdir may cause an error like overlayfs: failed to create directory ./workdir/work during mount. This patch check the *s_flags* of upper fs and return an error if it is a r/o partition. The checking of *upper_mnt->mnt_sb->s_flags* can be removed now. This patch also remove /* FIXME: workdir is not needed for a R/O mount */ from ovl_fill_super() because: 1) for upper fs r/o case Setting a r/o partition as upper is prevented, no need to care about workdir in this case. 2) for "mount overlay -o ro" with a r/w upper fs case Users could remount overlayfs to r/w in this case, so workdir should not be omitted. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-03-18ovl: check lowerdir amount for non-upper mounthujianyang1-1/+7
Recently multi-lower layer mount support allow upperdir and workdir to be omitted, then cause overlayfs can be mount with only one lowerdir directory. This action make no sense and have potential risk. This patch check the total number of lower directories to prevent mounting overlayfs with only one directory. Also, an error message is added to indicate lower directories exceed OVL_MAX_STACK limit. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-03-18ovl: print error message for invalid mount optionshujianyang1-0/+1
Overlayfs should print an error message if an incorrect mount option is caught like other filesystems. After this patch, improper option input could be clearly known. Reported-by: Fabian Sturm <fabian.sturm@aduu.de> Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-02-22VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)David Howells1-3/+3
Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-20Merge branch 'overlayfs-next' of ↵Al Viro6-319/+489
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into for-next
2015-01-09ovl: discard independent cursor in readdir()hujianyang1-24/+14
Since the ovl_dir_cache is stable during a directory reading, the cursor of struct ovl_dir_file don't need to be an independent entry in the list of a merged directory. This patch changes *cursor* to a pointer which points to the entry in the ovl_dir_cache. After this, we don't need to check *is_cursor* either. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-01-08ovl: Prevent rw remount when it should be ro mountSeunghun Lee1-0/+12
Overlayfs should be mounted read-only when upper-fs is read-only or nonexistent. But now it can be remounted read-write and this can cause kernel panic. So we should prevent read-write remount when the above situation happens. Signed-off-by: Seunghun Lee <waydi1@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-01-08ovl: Fix opaque regression in ovl_lookuphujianyang1-10/+13
Current multi-layer support overlayfs has a regression in .lookup(). If there is a directory in upperdir and a regular file has same name in lowerdir in a merged directory, lower file is hidden and upper directory is set to opaque in former case. But it is changed in present code. In lowerdir lookup path, if a found inode is not directory, the type checking of previous inode is missing. This inode will be copied to the lowerstack of ovl_entry directly. That will lead to several wrong conditions, for example, the reading of the directory in upperdir may return an error like: ls: reading directory .: Not a directory This patch makes the lowerdir lookup path check the opaque for non-directory file too. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-01-08ovl: Fix kernel panic while mounting overlayfshujianyang1-0/+3
The function ovl_fill_super() in recently multi-layer support version will incorrectly return 0 at error handling path and then cause kernel panic. This failure can be reproduced by mounting a overlayfs with upperdir and workdir in different mounts. And also, If the memory allocation of *lower_mnt* fail, this function may return an zero either. This patch fix this problem by setting *err* to proper error number before jumping to error handling path. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: Use macros to present ovl_xattrhujianyang4-7/+7
This patch adds two macros: OVL_XATTR_PRE_NAME and OVL_XATTR_PRE_LEN to present ovl_xattr name prefix and its length. Also, a new macro OVL_XATTR_OPAQUE is introduced to replace old *ovl_opaque_xattr*. Fix the length of "trusted.overlay." to *16*. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: Cleanup redundant blank lineshujianyang3-3/+0
This patch removes redundant blanks lines in overlayfs. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: support multiple lower layersMiklos Szeredi1-27/+83
Allow "lowerdir=" option to contain multiple lower directories separated by a colon (e.g. "lowerdir=/bin:/usr/bin"). Colon characters in filenames can be escaped with a backslash. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: make upperdir optionalMiklos Szeredi1-36/+47
Make "upperdir=" mount option optional. If "upperdir=" is not given, then the "workdir=" option is also optional (and ignored if given). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: improve mount helpersMiklos Szeredi1-52/+73
Move common checks into ovl_mount_dir() helper. Create helper for looking up lower directories. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: mount: change order of initializationMiklos Szeredi1-38/+32
Move allocation of root entry above to where it's needed. Move initializations related to upperdir and workdir near each other. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: allow statfs if no upper layerMiklos Szeredi1-2/+2
Handle "no upper layer" case in statfs. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: lookup ENAMETOOLONG on lower means ENOENTMiklos Szeredi1-1/+7
"Suppose you have in one of the lower layers a filesystem with ->lookup()-enforced upper limit on name length. Pretty much every local fs has one, but... they are not all equal. 255 characters is the common upper limit, but e.g. jffs2 stops at 254, minixfs upper limit is somewhere from 14 to 60, depending upon version, etc. You are doing a lookup for something that is present in upper layer, but happens to be too long for one of the lower layers. Too bad - ENAMETOOLONG for you..." Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: check whiteout on lowest layer as wellMiklos Szeredi2-56/+50
Not checking whiteouts on lowest layer was an optimization (there's nothing to white out there), but it could result in inconsitent behavior when a layer previously used as upper/middle is later used as lowest. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: multi-layer lookupMiklos Szeredi1-49/+94
Look up dentry in all relevant layers. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: multi-layer readdirMiklos Szeredi2-22/+24
If multiple lower layers exist, merge them as well in readdir according to the same rules as merging upper with lower. I.e. take whiteouts and opaque directories into account on all but the lowers layer. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: helper to iterate layersMiklos Szeredi2-0/+22
Add helper to iterate through all the layers, starting from the upper layer (if exists) and continuing down through the lower layers. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: add mutli-layer infrastructureMiklos Szeredi1-34/+64
Add multiple lower layers to 'struct ovl_fs' and 'struct ovl_entry'. ovl_entry will have an array of paths, instead of just the dentry. This allows a compact array containing just the layers which exist at current point in the tree (which is expected to be a small number for the majority of dentries). The number of layers is not limited by this infrastructure. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: dont replace opaque dirMiklos Szeredi1-1/+1
When removing an empty opaque directory, then it makes no sense to replace it with an exact replica of itself before removal. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: make path-type a bitmapMiklos Szeredi6-36/+41
OVL_PATH_PURE_UPPER -> __OVL_PATH_UPPER | __OVL_PATH_PURE OVL_PATH_UPPER -> __OVL_PATH_UPPER OVL_PATH_MERGE -> __OVL_PATH_UPPER | __OVL_PATH_MERGE OVL_PATH_LOWER -> 0 Multiple R/O layers will allow __OVL_PATH_MERGE without __OVL_PATH_UPPER. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: check whiteout while reading directoryMiklos Szeredi1-49/+28
Don't make a separate pass for checking whiteouts, since we can do it while reading the upper directory. This will make it easier to handle multiple layers. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-09Merge branch 'iov_iter' into for-nextAl Viro6-60/+106
2014-11-20ovl: ovl_dir_fsync() cleanupMiklos Szeredi1-2/+2
Check against !OVL_PATH_LOWER instead of OVL_PATH_MERGE. For a copied up directory the two are currently equivalent. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: pass dentry into ovl_dir_read_merged()Miklos Szeredi1-21/+14
Pass dentry into ovl_dir_read_merged() insted of upperpath and lowerpath. This cleans up callers and paves the way for multi-layer directory reads. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: use lockless_dereference() for upperdentryMiklos Szeredi1-6/+1
Don't open code lockless_dereference() in ovl_upperdentry_dereference(). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: allow filenames with commaMiklos Szeredi1-3/+45
Allow option separator (comma) to be escaped with backslash. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: fix race in private xattr checksMiklos Szeredi1-9/+18
Xattr operations can race with copy up. This does not matter as long as we consistently fiter out "trunsted.overlay.opaque" attribute on upper directories. Previously we checked parent against OVL_PATH_MERGE. This is too general, and prone to race with copy-up. I.e. we found the parent to be on the lower layer but ovl_dentry_real() would return the copied-up dentry, possibly with the "opaque" attribute. So instead use ovl_path_real() and decide to filter the attributes based on the actual type of the dentry we'll use. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: fix remove/copy-up raceMiklos Szeredi1-12/+19
ovl_remove_and_whiteout() needs to check if upper dentry exists or not after having locked upper parent directory. Previously we used a "type" value computed before locking the upper parent directory, which is susceptible to racing with copy-up. There's a similar check in ovl_check_empty_and_clear(). This one is not actually racy, since copy-up doesn't change the "emptyness" property of a directory. Add a comment to this effect, and check the existence of upper dentry locally to make the code cleaner. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-11-20ovl: rename filesystem type to "overlay"Miklos Szeredi3-6/+6
Some distributions carry an "old" format of overlayfs while mainline has a "new" format. The distros will possibly want to keep the old overlayfs alongside the new for compatibility reasons. To make it possible to differentiate the two versions change the name of the new one from "overlayfs" to "overlay". Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reported-by: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Andy Whitcroft <apw@canonical.com>
2014-11-05ovl: don't poison cursorMiklos Szeredi1-1/+1
ovl_cache_put() can be called from ovl_dir_reset() if the cache needs to be rebuilt. We did list_del() on the cursor, which results in an Oops on the poisoned pointer in ovl_seek_cursor(). Reported-by: Jordi Pujol Palomer <jordipujolp@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Tested-by: Jordi Pujol Palomer <jordipujolp@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>