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* ovl: fix format of setxattr debugMiklos Szeredi2018-10-041-2/+2
| | | | | | | | | | | Format has a typo: it was meant to be "%.*s", not "%*s". But at some point callers grew nonprintable values as well, so use "%*pE" instead with a maximized length. Reported-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up") Cc: <stable@vger.kernel.org> # v4.12
* ovl: fix access beyond unterminated stringsAmir Goldstein2018-10-041-1/+1
| | | | | | | | | | | | | | | | | | | KASAN detected slab-out-of-bounds access in printk from overlayfs, because string format used %*s instead of %.*s. > BUG: KASAN: slab-out-of-bounds in string+0x298/0x2d0 lib/vsprintf.c:604 > Read of size 1 at addr ffff8801c36c66ba by task syz-executor2/27811 > > CPU: 0 PID: 27811 Comm: syz-executor2 Not tainted 4.19.0-rc5+ #36 ... > printk+0xa7/0xcf kernel/printk/printk.c:1996 > ovl_lookup_index.cold.15+0xe8/0x1f8 fs/overlayfs/namei.c:689 Reported-by: syzbot+376cea2b0ef340db3dd4@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") Cc: <stable@vger.kernel.org> # v4.13
* ovl: make symbol 'ovl_aops' staticWei Yongjun2018-09-251-1/+1
| | | | | | | | | | | Fixes the following sparse warning: fs/overlayfs/inode.c:507:39: warning: symbol 'ovl_aops' was not declared. Should it be static? Fixes: 5b910bd615ba ("ovl: fix GPF in swapfile_activate of file from overlayfs over xfs") Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* vfs: swap names of {do,vfs}_clone_file_range()Amir Goldstein2018-09-242-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Commit 031a072a0b8a ("vfs: call vfs_clone_file_range() under freeze protection") created a wrapper do_clone_file_range() around vfs_clone_file_range() moving the freeze protection to former, so overlayfs could call the latter. The more common vfs practice is to call do_xxx helpers from vfs_xxx helpers, where freeze protecction is taken in the vfs_xxx helper, so this anomality could be a source of confusion. It seems that commit 8ede205541ff ("ovl: add reflink/copyfile/dedup support") may have fallen a victim to this confusion - ovl_clone_file_range() calls the vfs_clone_file_range() helper in the hope of getting freeze protection on upper fs, but in fact results in overlayfs allowing to bypass upper fs freeze protection. Swap the names of the two helpers to conform to common vfs practice and call the correct helpers from overlayfs and nfsd. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix freeze protection bypass in ovl_clone_file_range()Amir Goldstein2018-09-241-1/+1
| | | | | | | | | | | | | | | | Tested by doing clone on overlayfs while upper xfs+reflink is frozen: xfs_io -f /ovl/y fsfreeze -f /xfs xfs_io> reflink /ovl/x Before the fix xfs_io enters xfs_reflink_remap_range() and blocks in xfs_trans_alloc(). After the fix, xfs_io blocks outside xfs code in ovl_clone_file_range(). Fixes: 8ede205541ff ("ovl: add reflink/copyfile/dedup support") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix freeze protection bypass in ovl_write_iter()Amir Goldstein2018-09-241-0/+2
| | | | | | | | | | | | | | | | | | | | Tested by re-writing to an open overlayfs file while upper ext4 is frozen: xfs_io -f /ovl/x xfs_io> pwrite 0 4096 fsfreeze -f /ext4 xfs_io> pwrite 0 4096 WARNING: CPU: 0 PID: 1492 at fs/ext4/ext4_jbd2.c:53 \ ext4_journal_check_start+0x48/0x82 After the fix, the second write blocks in ovl_write_iter() and avoids hitting WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE) in ext4_journal_check_start(). Fixes: 2a92e07edc5e ("ovl: add ovl_write_iter()") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix memory leak on unlink of indexed fileAmir Goldstein2018-09-241-1/+2
| | | | | | | | | | The memory leak was detected by kmemleak when running xfstests overlay/051,053 Fixes: caf70cb2ba5d ("ovl: cleanup orphan index entries") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix oopses in ovl_fill_super() failure pathsMiklos Szeredi2018-09-101-12/+14
| | | | | | | | | | | | | ovl_free_fs() dereferences ofs->workbasedir and ofs->upper_mnt in cases when those might not have been initialized yet. Fix the initialization order for these fields. Reported-by: syzbot+c75f181dc8429d2eb887@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> # v4.15 Fixes: 95e6d4177cb7 ("ovl: grab reference to workbasedir early") Fixes: a9075cdb467d ("ovl: factor out ovl_free_fs() helper")
* ovl: add ovl_fadvise()Amir Goldstein2018-09-031-0/+20
| | | | | | | | | | Implement stacked fadvise to fix syscalls readahead(2) and fadvise64(2) on an overlayfs file. Suggested-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: d1d04ef8572b ("ovl: stack file ops") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix GPF in swapfile_activate of file from overlayfs over xfsAmir Goldstein2018-08-302-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since overlayfs implements stacked file operations, the underlying filesystems are not supposed to be exposed to the overlayfs file, whose f_inode is an overlayfs inode. Assigning an overlayfs file to swap_file results in an attempt of xfs code to dereference an xfs_inode struct from an ovl_inode pointer: CPU: 0 PID: 2462 Comm: swapon Not tainted 4.18.0-xfstests-12721-g33e17876ea4e #3402 RIP: 0010:xfs_find_bdev_for_inode+0x23/0x2f Call Trace: xfs_iomap_swapfile_activate+0x1f/0x43 __se_sys_swapon+0xb1a/0xee9 Fix this by not assigning the real inode mapping to f_mapping, which will cause swapon() to return an error (-EINVAL). Although it makes sense not to allow setting swpafile on an overlayfs file, some users may depend on it, so we may need to fix this up in the future. Keeping f_mapping pointing to overlay inode mapping will cause O_DIRECT open to fail. Fix this by installing ovl_aops with noop_direct_IO in overlay inode mapping. Keeping f_mapping pointing to overlay inode mapping will cause other a_ops related operations to fail (e.g. readahead()). Those will be fixed by follow up patches. Suggested-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: f7c72396d0de ("ovl: add O_DIRECT support") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: respect FIEMAP_FLAG_SYNC flagAmir Goldstein2018-08-301-0/+4
| | | | | | | | | | Stacked overlayfs fiemap operation broke xfstests that test delayed allocation (with "_test_generic_punch -d"), because ovl_fiemap() failed to write dirty pages when requested. Fixes: 9e142c4102db ("ovl: add ovl_fiemap()") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: set I_CREATING on inode being createdMiklos Szeredi2018-08-221-0/+4
| | | | | | | | | ...otherwise there will be list corruption due to inode_sb_list_add() being called for inode already on the sb list. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: e950564b97fd ("vfs: don't evict uninitialized inode") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ovl: Enable metadata only featureVivek Goyal2018-07-201-3/+0
| | | | | | | | | All the bits are in patches before this. So it is time to enable the metadata only copy up feature. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Do not do metacopy only for ioctl modifying file attrVivek Goyal2018-07-201-1/+1
| | | | | | | | | | | | | | | | | | ovl_copy_up() by default will only do metadata only copy up (if enabled). That means when ovl_real_ioctl() calls ovl_real_file(), it will still get the lower file (as ovl_real_file() opens data file and not metacopy). And that means "chattr +i" will end up modifying lower inode. There seem to be two ways to solve this. A. Open metacopy file in ovl_real_ioctl() and do operations on that B. Force full copy up when FS_IOC_SETFLAGS is called. I am resorting to option B for now as it feels little safer option. If there are performance issues due to this, we can revisit it. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Do not do metadata only copy-up for truncate operationVivek Goyal2018-07-201-1/+8
| | | | | | | | | | | | | | | | | truncate should copy up full file (and not do metacopy only), otherwise it will be broken. For example, use truncate to increase size of a file so that any read beyong existing size will return null bytes. If we don't copy up full file, then we end up opening lower file and read from it only reads upto the old size (and not new size after truncate). Hence to avoid such situations, copy up data as well when file size changes. So far it was being done by d_real(O_WRONLY) call in truncate() path. Now that patch has been reverted. So force full copy up in ovl_setattr() if size of file is changing. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add helper to force data copy-upVivek Goyal2018-07-202-0/+6
| | | | | | Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Check redirect on index as wellVivek Goyal2018-07-203-37/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Right now we seem to check redirect only if upperdentry is found. But it is possible that there is no upperdentry but later we found an index. We need to check redirect on index as well and set it in ovl_inode->redirect. Otherwise link code can assume that dentry does not have redirect and place a new one which breaks things. In my testing overlay/033 test started failing in xfstests. Following are the details. For example do following. $ mkdir lower upper work merged - Make lower dir with 4 links. $ echo "foo" > lower/l0.txt $ ln lower/l0.txt lower/l1.txt $ ln lower/l0.txt lower/l2.txt $ ln lower/l0.txt lower/l3.txt - Mount with index on and metacopy on. $ mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work,\ index=on,metacopy=on none merged - Link lower $ ln merged/l0.txt merged/l4.txt (This will metadata copy up of l0.txt and put an absolute redirect /l0.txt) $ echo 2 > /proc/sys/vm/drop/caches $ ls merged/l1.txt (Now l1.txt will be looked up. There is no upper dentry but there is lower dentry and index will be found. We don't check for redirect on index, hence ovl_inode->redirect will be NULL.) - Link Upper $ ln merged/l4.txt merged/l5.txt (Lookup of l4.txt will use inode from l1.txt lookup which is still in cache. It has ovl_inode->redirect NULL, hence link will put a new redirect and replace /l0.txt with /l4.txt - Drop caches. echo 2 > /proc/sys/vm/drop_caches - List l1.txt and it returns -ESTALE $ ls merged/l0.txt (It returns stale because, we found a metacopy of l0.txt in upper and it has redirect l4.txt but there is no file named l4.txt in lower layer. So lower data copy is not found and -ESTALE is returned.) So problem here is that we did not process redirect on index. Check redirect on index as well and then problem is fixed. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Set redirect on upper inode when it is linkedVivek Goyal2018-07-201-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we create a hardlink to a metacopy upper file, first the redirect on that inode. Path based lookup will not work with newly created link and redirect will solve that issue. Also use absolute redirect as two hardlinks could be in different directores and relative redirect will not work. I have not put any additional locking around setting redirects while introducing redirects for non-dir files. For now it feels like existing locking is sufficient. If that's not the case, we will have add more locking. Following is my rationale about why do I think current locking seems ok. Basic problem for non-dir files is that more than on dentry could be pointing to same inode and in theory only relying on dentry based locks (d->d_lock) did not seem sufficient. We set redirect upon rename and upon link creation. In both the paths for non-dir file, VFS locks both source and target inodes (->i_rwsem). That means vfs rename and link operations on same source and target can't he happening in parallel (Even if there are multiple dentries pointing to same inode). So that probably means that at a time on an inode, only one call of ovl_set_redirect() could be working and we don't need additional locking in ovl_set_redirect(). ovl_inode->redirect is initialized only when inode is created new. That means it should not race with any other path and setting ovl_inode->redirect should be fine. Reading of ovl_inode->redirect happens in ovl_get_redirect() path. And this called only in ovl_set_redirect(). And ovl_set_redirect() already seemed to be protected using ->i_rwsem. That means ovl_set_redirect() and ovl_get_redirect() on source/target inode should not make progress in parallel and is mutually exclusive. Hence no additional locking required. Now, only case where ovl_set_redirect() and ovl_get_redirect() could race seems to be case of absolute redirects where ovl_get_redirect() has to travel up the tree. In that case we already take d->d_lock and that should be sufficient as directories will not have multiple dentries pointing to same inode. So given VFS locking and current usage of redirect, current locking around redirect seems to be ok for non-dir as well. Once we have the logic to remove redirect when metacopy file gets copied up, then we probably will need additional locking. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Set redirect on metacopy files upon renameVivek Goyal2018-07-201-20/+46
| | | | | | | | | Set redirect on metacopy files upon rename. This will help find data dentry in lower dirs. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Do not set dentry type ORIGIN for broken hardlinksVivek Goyal2018-07-201-1/+2
| | | | | | | | | | | | | | | | | | | | | | | If a dentry has copy up origin, we set flag OVL_PATH_ORIGIN. So far this decision was easy that we had to check only for oe->numlower and if it is non-zero, we knew there is copy up origin. (For non-dir we installed origin dentry in lowerstack[0]). But we don't create ORGIN xattr for broken hardlinks (index=off). And with metacopy feature it is possible that we will install lowerstack[0] but ORIGIN xattr is not there. It is data dentry of upper metacopy dentry which has been found using regular name based lookup or using REDIRECT. So with addition of this new case, just presence of oe->numlower is not sufficient to guarantee that ORIGIN xattr is present. So to differentiate between two cases, look at OVL_CONST_INO flag. If this flag is set and upperdentry is there, that means it can be marked as type ORIGIN. OVL_CONST_INO is not set if lower hardlink is broken or will be broken over copy up. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Add an inode flag OVL_CONST_INOVivek Goyal2018-07-202-0/+5
| | | | | | | | | | | | | | | | | Add an ovl_inode flag OVL_CONST_INO. This flag signifies if inode number will remain constant over copy up or not. This flag does not get updated over copy up and remains unmodifed after setting once. Next patch in the series will make use of this flag. It will basically figure out if dentry is of type ORIGIN or not. And this can be derived by this flag. ORIGIN = (upperdentry && ovl_test_flag(OVL_CONST_INO, inode)). Suggested-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Treat metacopy dentries as type OVL_PATH_MERGEVivek Goyal2018-07-201-1/+2
| | | | | | | | | | | | | Right now OVL_PATH_MERGE is used only for merged directories. But conceptually, a metacopy dentry (backed by a lower data dentry) is a merged entity as well. So mark metacopy dentries as OVL_PATH_MERGE and ovl_rename() makes use of this property later to set redirect on a metacopy file. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Check redirects for metacopy filesVivek Goyal2018-07-201-2/+2
| | | | | | | | | | | | | Right now we rely on path based lookup for data origin of metacopy upper. This will work only if upper has not been renamed. We solved this problem already for merged directories using redirect. Use same logic for metacopy files. This patch just goes on to check redirects for metacopy files. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Move some dir related ovl_lookup_single() code in else blockVivek Goyal2018-07-201-10/+11
| | | | | | | | | | | | | Move some directory related code in else block. This is pure code reorganization and no functionality change. Next patch enables redirect processing on metacopy files and needs this change. By keeping non-functional changes in a separate patch, next patch looks much smaller and cleaner. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Do not expose metacopy only dentry from d_real()Vivek Goyal2018-07-201-2/+5
| | | | | | | | | | | Metacopy dentry/inode is internal to overlay and is never exposed outside of it. Exception is metacopy upper file used for fsync(). Modify d_real() to look for dentries/inode which have data, but also allow matching upper inode without data for the fsync case. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Open file with data except for the case of fsyncVivek Goyal2018-07-201-9/+30
| | | | | | | | | | | | | | | | | | | ovl_open() should open file which contains data and not open metacopy inode. With the introduction of metacopy inodes, with current implementaion we will end up opening metacopy inode as well. But there can be certain circumstances like ovl_fsync() where we want to allow opening a metacopy inode instead. Hence, change ovl_open_realfile() and and add extra parameter which specifies whether to allow opening metacopy inode or not. If this parameter is false, we look for data inode and open that. This should allow covering both the cases. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Add helper ovl_inode_realdata()Vivek Goyal2018-07-202-0/+13
| | | | | | | | | | Add an helper to retrieve real data inode associated with overlay inode. This helper will ignore all metacopy inodes and will return only the real inode which has data. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Store lower data inode in ovl_inodeVivek Goyal2018-07-206-6/+27
| | | | | | | | | | | | | | | | | Right now ovl_inode stores inode pointer for lower inode. This helps with quickly getting lower inode given overlay inode (ovl_inode_lower()). Now with metadata only copy-up, we can have metacopy inode in middle layer as well and inode containing data can be different from ->lower. I need to be able to open the real file in ovl_open_realfile() and for that I need to quickly find the lower data inode. Hence store lower data inode also in ovl_inode. Also provide an helper ovl_inode_lowerdata() to access this field. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Fix ovl_getattr() to get number of blocks from lowerVivek Goyal2018-07-203-1/+51
| | | | | | | | | | | | | | | | | | | | If an inode has been copied up metadata only, then we need to query the number of blocks from lower and fill up the stat->st_blocks. We need to be careful about races where we are doing stat on one cpu and data copy up is taking place on other cpu. We want to return stat->st_blocks either from lower or stable upper and not something in between. Hence, ovl_has_upperdata() is called first to figure out whether block reporting will take place from lower or upper. We now support metacopy dentries in middle layer. That means number of blocks reporting needs to come from lowest data dentry and this could be different from lower dentry. Hence we end up making a separate vfs_getxattr() call for metacopy dentries to get number of blocks. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Add helper ovl_dentry_lowerdata() to get lower data dentryVivek Goyal2018-07-202-0/+14
| | | | | | | | | | | | | | | Now we have the notion of data dentry and metacopy dentry. ovl_dentry_lower() will return uppermost lower dentry, but it could be either data or metacopy dentry. Now we support metacopy dentries in lower layers so it is possible that lowerstack[0] is metacopy dentry while lowerstack[1] is actual data dentry. So add an helper which returns lowest most dentry which is supposed to be data dentry. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Copy up meta inode data from lowest data inodeVivek Goyal2018-07-203-4/+22
| | | | | | | | | | | | | | | | So far lower could not be a meta inode. So whenever it was time to copy up data of a meta inode, we could copy it up from top most lower dentry. But now lower itself can be a metacopy inode. That means data copy up needs to take place from a data inode in metacopy inode chain. Find lower data inode in the chain and use that for data copy up. Introduced a helper called ovl_path_lowerdata() to find the lower data inode chain. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Modify ovl_lookup() and friends to lookup metacopy dentryVivek Goyal2018-07-205-18/+131
| | | | | | | | | | | | | | | | | | | | This patch modifies ovl_lookup() and friends to lookup metacopy dentries. It also allows for presence of metacopy dentries in lower layer. During lookup, check for presence of OVL_XATTR_METACOPY and if not present, set OVL_UPPERDATA bit in flags. We don't support metacopy feature with nfs_export. So in nfs_export code, we set OVL_UPPERDATA flag set unconditionally if upper inode exists. Do not follow metacopy origin if we find a metacopy only inode and metacopy feature is not enabled for that mount. Like redirect, this can have security implications where an attacker could hand craft upper and try to gain access to file on lower which it should not have to begin with. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Use out_err instead of out_nomemVivek Goyal2018-07-201-7/+10
| | | | | | | | | | | | | | | | Right now we use goto out_nomem which assumes error code is -ENOMEM. But there are other errors returned like -ESTALE as well. So instead of out_nomem, use out_err which will do ERR_PTR(err). That way one can put error code in err and jump to out_err. This just code reorganization and no change of functionality. I am about to add more code and this organization helps laying more code and error paths on top of it. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: A new xattr OVL_XATTR_METACOPY for file on upperVivek Goyal2018-07-204-11/+142
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now we will have the capability to have upper inodes which might be only metadata copy up and data is still on lower inode. So add a new xattr OVL_XATTR_METACOPY to distinguish between two cases. Presence of OVL_XATTR_METACOPY reflects that file has been copied up metadata only and and data will be copied up later from lower origin. So this xattr is set when a metadata copy takes place and cleared when data copy takes place. We also use a bit in ovl_inode->flags to cache OVL_UPPERDATA which reflects whether ovl inode has data or not (as opposed to metadata only copy up). If a file is copied up metadata only and later when same file is opened for WRITE, then data copy up takes place. We copy up data, remove METACOPY xattr and then set the UPPERDATA flag in ovl_inode->flags. While all these operations happen with oi->lock held, read side of oi->flags can be lockless. That is another thread on another cpu can check if UPPERDATA flag is set or not. So this gives us an ordering requirement w.r.t UPPERDATA flag. That is, if another cpu sees UPPERDATA flag set, then it should be guaranteed that effects of data copy up and remove xattr operations are also visible. For example. CPU1 CPU2 ovl_open() acquire(oi->lock) ovl_open_maybe_copy_up() ovl_copy_up_data() open_open_need_copy_up() vfs_removexattr() ovl_already_copied_up() ovl_dentry_needs_data_copy_up() ovl_set_flag(OVL_UPPERDATA) ovl_test_flag(OVL_UPPERDATA) release(oi->lock) Say CPU2 is copying up data and in the end sets UPPERDATA flag. But if CPU1 perceives the effects of setting UPPERDATA flag but not the effects of preceding operations (ex. upper that is not fully copied up), it will be a problem. Hence this patch introduces smp_wmb() on setting UPPERDATA flag operation and smp_rmb() on UPPERDATA flag test operation. May be some other lock or barrier is already covering it. But I am not sure what that is and is it obvious enough that we will not break it in future. So hence trying to be safe here and introducing barriers explicitly for UPPERDATA flag/bit. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Add helper ovl_already_copied_up()Vivek Goyal2018-07-203-19/+28
| | | | | | | | | | | | There are couple of places where we need to know if file is already copied up (in lockless manner). Right now its open coded and there are only two conditions to check. Soon this patch series will introduce another condition to check and Amir wants to introduce one more. So introduce a helper instead to check this so that code is easier to read. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Copy up only metadata during copy up where it makes senseVivek Goyal2018-07-201-1/+24
| | | | | | | | | | | | If it makes sense to copy up only metadata during copy up, do it. This is done for regular files which are not opened for WRITE. Right now ->metacopy is set to 0 always. Last patch in the series will remove the hard coded statement and enable metacopy feature. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: During copy up, first copy up metadata and then dataVivek Goyal2018-07-201-19/+17
| | | | | | | | | Just a little re-ordering of code. This helps with next patch where after copying up metadata, we skip data copying step, if needed. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Provide a mount option metacopy=on/off for metadata copyupVivek Goyal2018-07-203-3/+63
| | | | | | | | | | | | | | | | | | By default metadata only copy up is disabled. Provide a mount option so that users can choose one way or other. Also provide a kernel config and module option to enable/disable metacopy feature. metacopy feature requires redirect_dir=on when upper is present. Otherwise, it requires redirect_dir=follow atleast. As of now, metacopy does not work with nfs_export=on. So if both metacopy=on and nfs_export=on then nfs_export is disabled. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Move the copy up helpers to copy_up.cVivek Goyal2018-07-203-33/+33
| | | | | | | | | | | Right now two copy up helpers are in inode.c. Amir suggested it might be better to move these to copy_up.c. There will one more related function which will come in later patch. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Initialize ovl_inode->redirect in ovl_get_inode()Vivek Goyal2018-07-203-7/+5
| | | | | | | | | | | | | | | | | ovl_inode->redirect is an inode property and should be initialized in ovl_get_inode() only when we are adding a new inode to cache. If inode is already in cache, it is already initialized and we should not be touching ovl_inode->redirect field. As of now this is not a problem as redirects are used only for directories which don't share inode. But soon I want to use redirects for regular files also and there it can become an issue. Hence, move ->redirect initialization in ovl_get_inode(). Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: obsolete "check_copy_up" module optionMiklos Szeredi2018-07-181-23/+7
| | | | | | | This was provided for debugging the ro/rw inconsistecy. The inconsitency is now gone so this option is obsolete. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* vfs: remove open_flags from d_real()Miklos Szeredi2018-07-181-33/+3
| | | | | | | | Opening regular files on overlayfs is now handled via ovl_open(). Remove the now unused "open_flags" argument from d_op->d_real() and the d_real() helper. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Partially revert "locks: fix file locking on overlayfs"Miklos Szeredi2018-07-181-1/+1
| | | | | | | | | | | | | | | | | | | This partially reverts commit c568d68341be7030f5647def68851e469b21ca11. Overlayfs files will now automatically get the correct locks, no need to hack overlay support in VFS. It is a partial revert, because it leaves the locks_inode() calls in place and defines locks_inode() to file_inode(). We could revert those as well, but it would be unnecessary code churn and it makes sense to document that we are getting the inode for locking purposes. Don't revert MS_NOREMOTELOCK yet since that has been part of the userspace API for some time (though not in a useful way). Will try to remove internal flags later when the dust around the new mount API settles. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org>
* Revert "vfs: add flags to d_real()"Miklos Szeredi2018-07-181-2/+2
| | | | | | | | This reverts commit 495e642939114478a5237a7d91661ba93b76f15a. No user of "flags" argument of d_real() remain. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Revert "ovl: fix relatime for directories"Miklos Szeredi2018-07-181-3/+0
| | | | | | | | This reverts commit cd91304e7190b4c4802f8e413ab2214b233e0260. Overlayfs no longer relies on the vfs correct atime handling. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add reflink/copyfile/dedup supportMiklos Szeredi2018-07-181-0/+87
| | | | | | Since set of arguments are so similar, handle in a common helper. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add O_DIRECT supportMiklos Szeredi2018-07-181-0/+3
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add ovl_fiemap()Miklos Szeredi2018-07-181-1/+28
| | | | | | | | | Implement stacked fiemap(). Need to split inode operations for regular file (which has fiemap) and special file (which doesn't have fiemap). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add lsattr/chattr supportMiklos Szeredi2018-07-181-0/+79
| | | | | | Implement FS_IOC_GETFLAGS and FS_IOC_SETFLAGS. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add ovl_fallocate()Miklos Szeredi2018-07-181-0/+24
| | | | | | Implement stacked fallocate. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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