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* ovl: consistent i_ino for non-samefs with xinoAmir Goldstein2018-04-121-1/+1
| | | | | | | | | | | | When overlay layers are not all on the same fs, but all inode numbers of underlying fs do not use the high 'xino' bits, overlay st_ino values are constant and persistent. In that case, set i_ino value to the same value as st_ino for nfsd readdirplus validator. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: constant st_ino for non-samefs with xinoAmir Goldstein2018-04-121-1/+8
| | | | | | | | | | | | | | | | On 64bit systems, when overlay layers are not all on the same fs, but all inode numbers of underlying fs are not using the high bits, use the high bits to partition the overlay st_ino address space. The high bits hold the fsid (upper fsid is 0). This way overlay inode numbers are unique and all inodes use overlay st_dev. Inode numbers are also persistent for a given layer configuration. Currently, our only indication for available high ino bits is from a filesystem that supports file handles and uses the default encode_fh() operation, which encodes a 32bit inode number. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: factor out ovl_map_dev_ino() helperAmir Goldstein2018-04-121-0/+1
| | | | | | | | A helper for ovl_getattr() to map the values of st_dev and st_ino according to constant st_ino rules. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: do not try to reconnect a disconnected origin dentryAmir Goldstein2018-04-121-2/+3
| | | | | | | | | | | | | | | | | | | | | | | On lookup of non directory, we try to decode the origin file handle stored in upper inode. The origin file handle is supposed to be decoded to a disconnected non-dir dentry, which is fine, because we only need the lower inode of a copy up origin. However, if the origin file handle somehow turns out to be a directory we pay the expensive cost of reconnecting the directory dentry, only to get a mismatch file type and drop the dentry. Optimize this case by explicitly opting out of reconnecting the dentry. Opting-out of reconnect is done by passing a NULL acceptable callback to exportfs_decode_fh(). While the case described above is a strange corner case that does not really need to be optimized, the API added for this optimization will be used by a following patch to optimize a more common case of decoding an overlayfs file handle. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: disambiguate ovl_encode_fh()Amir Goldstein2018-04-121-2/+2
| | | | | | | | | | | Rename ovl_encode_fh() to ovl_encode_real_fh() to differentiate from the exportfs function ovl_encode_inode_fh() and change the latter to ovl_encode_fh() to match the exportfs method name. Rename ovl_decode_fh() to ovl_decode_real_fh() for consistency. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: check lower ancestry on encode of lower dir file handleAmir Goldstein2018-02-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change relaxes copy up on encode of merge dir with lower layer > 1 and handles the case of encoding a merge dir with lower layer 1, where an ancestor is a non-indexed merge dir. In that case, decode of the lower file handle will not have been possible if the non-indexed ancestor is redirected before or after encode. Before encoding a non-upper directory file handle from real layer N, we need to check if it will be possible to reconnect an overlay dentry from the real lower decoded dentry. This is done by following the overlay ancestry up to a "layer N connected" ancestor and verifying that all parents along the way are "layer N connectable". If an ancestor that is NOT "layer N connectable" is found, we need to copy up an ancestor, which is "layer N connectable", thus making that ancestor "layer N connected". For example: layer 1: /a layer 2: /a/b/c The overlay dentry /a is NOT "layer 2 connectable", because if dir /a is copied up and renamed, upper dir /a will be indexed by lower dir /a from layer 1. The dir /a from layer 2 will never be indexed, so the algorithm in ovl_lookup_real_ancestor() (*) will not be able to lookup a connected overlay dentry from the connected lower dentry /a/b/c. To avoid this problem on decode time, we need to copy up an ancestor of /a/b/c, which is "layer 2 connectable", on encode time. That ancestor is /a/b. After copy up (and index) of /a/b, it will become "layer 2 connected" and when the time comes to decode the file handle from lower dentry /a/b/c, ovl_lookup_real_ancestor() will find the indexed ancestor /a/b and decoding a connected overlay dentry will be accomplished. (*) the algorithm in ovl_lookup_real_ancestor() can be improved to lookup an entry /a in the lower layers above layer N and find the indexed dir /a from layer 1. If that improvement is made, then the check for "layer N connected" will need to verify there are no redirects in lower layers above layer N. In the example above, /a will be "layer 2 connectable". However, if layer 2 dir /a is a target of a layer 1 redirect, then /a will NOT be "layer 2 connectable": layer 1: /A (redirect = /a) layer 2: /a/b/c Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: lookup indexed ancestor of lower dirAmir Goldstein2018-01-241-0/+2
| | | | | | | | | | | | | | | ovl_lookup_real() in lower layer walks back lower parents to find the topmost indexed parent. If an indexed ancestor is found before reaching lower layer root, ovl_lookup_real() is called recursively with upper layer to walk back from indexed upper to the topmost connected/hashed upper parent (or up to root). ovl_lookup_real() in upper layer then walks forward to connect the topmost upper overlay dir dentry and ovl_lookup_real() in lower layer continues to walk forward to connect the decoded lower overlay dir dentry. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: lookup connected ancestor of dir in inode cacheAmir Goldstein2018-01-241-1/+2
| | | | | | | | | | | | Decoding a dir file handle requires walking backward up to layer root and for lower dir also checking the index to see if any of the parents have been copied up. Lookup overlay ancestor dentry in inode/dentry cache by decoded real parents to shortcut looking up all the way back to layer root. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: decode indexed dir file handlesAmir Goldstein2018-01-241-0/+1
| | | | | | | | | | Decoding an indexed dir file handle is done by looking up the file handle in index dir by name and then decoding the upper dir from the index origin file handle. The decoded upper path is used to lookup an overlay dentry of the same path. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: decode lower file handles of unlinked but open filesAmir Goldstein2018-01-241-0/+1
| | | | | | | | | Lookup overlay inode in cache by origin inode, so we can decode a file handle of an open file even if the index has a whiteout index entry to mark this overlay inode was unlinked. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: decode lower non-dir file handlesAmir Goldstein2018-01-241-0/+2
| | | | | | | | | | Decoding a lower non-dir file handle is done by decoding the lower dentry from underlying lower fs, finding or allocating an overlay inode that is hashed by the real lower inode and instantiating an overlay dentry with that inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: decode pure upper file handlesAmir Goldstein2018-01-241-0/+2
| | | | | | | | | | Decoding an upper file handle is done by decoding the upper dentry from underlying upper fs, finding or allocating an overlay inode that is hashed by the real upper inode and instantiating an overlay dentry with that inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: encode pure upper file handlesAmir Goldstein2018-01-241-0/+6
| | | | | | | | Encode overlay file handles as struct ovl_fh containing the file handle encoding of the real upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: store 'has_upper' and 'opaque' as bit flagsAmir Goldstein2018-01-241-1/+9
| | | | | | | | | We need to make some room in struct ovl_entry to store information about redirected ancestors for NFS export, so cram two booleans as bit flags. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: do not pass overlay dentry to ovl_get_inode()Amir Goldstein2018-01-241-2/+3
| | | | | | | | This is needed for using ovl_get_inode() for decoding file handles for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: factor out ovl_get_index_fh() helperAmir Goldstein2018-01-241-0/+1
| | | | | | | The helper is needed to lookup an index by file handle for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: whiteout index when union nlink drops to zeroAmir Goldstein2018-01-241-0/+2
| | | | | | | | | | | | With NFS export feature enabled, when overlay inode nlink drops to zero, instead of removing the index entry, replace it with a whiteout index entry. This is needed for NFS export in order to prevent future open by handle from opening the lower file directly. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: create ovl_need_index() helperAmir Goldstein2018-01-241-0/+1
| | | | | | | | | | The helper determines which lower file needs to be indexed on copy up and before nlink changes. For index=on, the helper evaluates to true for lower hardlinks. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: use directory index entries for consistency verificationAmir Goldstein2018-01-241-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | A directory index is a directory type entry in index dir with a "trusted.overlay.upper" xattr containing an encoded ovl_fh of the merge directory upper dir inode. On lookup of non-dir files, lower file is followed by origin file handle. On lookup of dir entries, lower dir is found by name and then compared to origin file handle. We only trust dir index if we verified that lower dir matches origin file handle, otherwise index may be inconsistent and we ignore it. If we find an indexed non-upper dir or an indexed merged dir, whose index 'upper' xattr points to a different upper dir, that means that the lower directory may be also referenced by another upper dir via redirect, so we fail the lookup on inconsistency error. To be consistent with directory index entries format, the association of index dir to upper root dir, that was stored by older kernels in "trusted.overlay.origin" xattr is now stored in "trusted.overlay.upper" xattr. This also serves as an indication that overlay was mounted with a kernel that support index directory entries. For backward compatibility, if an 'origin' xattr exists on the index dir we also verify it on mount. Directory index entries are going to be used for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add support for "nfs_export" configurationAmir Goldstein2018-01-241-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | Introduce the "nfs_export" config, module and mount options. The NFS export feature depends on the "index" feature and enables two implicit overlayfs features: "index_all" and "verify_lower". The "index_all" feature creates an index on copy up of every file and directory. The "verify_lower" feature uses the full index to detect overlay filesystems inconsistencies on lookup, like redirect from multiple upper dirs to the same lower dir. NFS export can be enabled for non-upper mount with no index. However, because lower layer redirects cannot be verified with the index, enabling NFS export support on an overlay with no upper layer requires turning off redirect follow (e.g. "redirect_dir=nofollow"). The full index may incur some overhead on mount time, especially when verifying that lower directory file handles are not stale. NFS export support, full index and consistency verification will be implemented by following patches. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: generalize ovl_verify_origin() and helpersAmir Goldstein2018-01-241-3/+9
| | | | | | | | | | | | | | | | | | Remove the "origin" language from the functions that handle set, get and verify of "origin" xattr and pass the xattr name as an argument. The same helpers are going to be used for NFS export to get, get and verify the "upper" xattr for directory index entries. ovl_verify_origin() is now a helper used only to verify non upper file handle stored in "origin" xattr of upper inode. The upper root dir file handle is still stored in "origin" xattr on the index dir for backward compatibility. This is going to be changed by the patch that adds directory index entries support. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: simplify arguments to ovl_check_origin_fh()Amir Goldstein2018-01-241-5/+4
| | | | | | | | | | | | Pass the fs instance with lower_layers array instead of the dentry lowerstack array to ovl_check_origin_fh(), because the dentry members of lowerstack play no role in this helper. This change simplifies the argument list of ovl_check_origin(), ovl_cleanup_index() and ovl_verify_index(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix inconsistent d_ino for legacy merge dirAmir Goldstein2018-01-241-0/+2
| | | | | | | | | | | | | | | | For a merge dir that was copied up before v4.12 or that was hand crafted offline (e.g. mkdir {upper/lower}/dir), upper dir does not contain the 'trusted.overlay.origin' xattr. In that case, stat(2) on the merge dir returns the lower dir st_ino, but getdents(2) returns the upper dir d_ino. After this change, on merge dir lookup, missing origin xattr on upper dir will be fixed and 'impure' xattr will be fixed on parent of the legacy merge dir. Suggested-by: zhangyi (F) <yi.zhang@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: Use PTR_ERR_OR_ZERO()Vasyl Gomonovych2017-12-111-1/+1
| | | | | | | | | | | | Fix ptr_ret.cocci warnings: fs/overlayfs/overlayfs.h:179:11-17: WARNING: PTR_ERR_OR_ZERO can be used Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR Generated by: scripts/coccinelle/api/ptr_ret.cocci Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: remove unneeded arg from ovl_verify_origin()Amir Goldstein2017-11-101-2/+2
| | | | | Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: re-structure overlay lower layers in-memoryChandan Rajendra2017-11-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Define new structures to represent overlay instance lower layers and overlay merge dir lower layers to make room for storing more per layer information in-memory. Instead of keeping the fs instance lower layers in an array of struct vfsmount, keep them in an array of new struct ovl_layer, that has a pointer to struct vfsmount. Instead of keeping the dentry lower layers in an array of struct path, keep them in an array of new struct ovl_path, that has a pointer to struct dentry and to struct ovl_layer. Add a small helper to find the fs layer id that correspopnds to a lower struct ovl_path and use it in ovl_lookup(). [amir: split re-structure from anonymous bdev patch] Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: move include of ovl_entry.h into overlayfs.hAmir Goldstein2017-11-091-0/+1
| | | | | | | | | | | | | Most overlayfs c files already explicitly include ovl_entry.h to use overlay entry struct definitions and upcoming changes are going to require even more c files to include this header. All overlayfs c files include overlayfs.h and overlayfs.h itself refers to some structs defined in ovl_entry.h, so it seems more logic to include ovl_entry.h from overlayfs.h than from c files. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: no direct iteration for dir with origin xattrAmir Goldstein2017-11-091-0/+4
| | | | | | | | | | | | | | | | If a non-merge dir in an overlay mount has an overlay.origin xattr, it means it was once an upper merge dir, which may contain whiteouts and then the lower dir was removed under it. Do not iterate real dir directly in this case to avoid exposing whiteouts. [SzM] Set OVL_WHITEOUT for all merge directories as well. [amir] A directory that was just copied up does not have the OVL_WHITEOUTS flag. We need to set it to fix merge dir iteration. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix EIO from lookup of non-indexed upperAmir Goldstein2017-10-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Commit fbaf94ee3cd5 ("ovl: don't set origin on broken lower hardlink") attempt to avoid the condition of non-indexed upper inode with lower hardlink as origin. If this condition is found, lookup returns EIO. The protection of commit mentioned above does not cover the case of lower that is not a hardlink when it is copied up (with either index=off/on) and then lower is hardlinked while overlay is offline. Changes to lower layer while overlayfs is offline should not result in unexpected behavior, so a permanent EIO error after creating a link in lower layer should not be considered as correct behavior. This fix replaces EIO error with success in cases where upper has origin but no index is found, or index is found that does not match upper inode. In those cases, lookup will not fail and the returned overlay inode will be hashed by upper inode instead of by lower origin inode. Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") 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 missing unlock_rename() in ovl_do_copy_up()Amir Goldstein2017-10-051-0/+1
| | | | | | | | | | Use the ovl_lock_rename_workdir() helper which requires unlock_rename() only on lock success. Fixes: ("fd210b7d67ee ovl: move copy up lock out") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: constant d_ino for non-merge dirsMiklos Szeredi2017-07-271-3/+5
| | | | | | | | | | | | | | | | | | | | | | Impure directories are ones which contain objects with origins (i.e. those that have been copied up). These are relevant to readdir operation only because of the d_ino field, no other transformation is necessary. Also a directory can become impure between two getdents(2) calls. This patch creates a cache for impure directories. Unlike the cache for merged directories, this one only contains entries with origin and is not refcounted but has a its lifetime tied to that of the dentry. Similarly to the merged cache, the impure cache is invalidated based on a version number. This version number is incremented when an entry with origin is added or removed from the directory. If the cache is empty, then the impure xattr is removed from the directory. This patch also fixes up handling of d_ino for the ".." entry if the parent directory is merged. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix xattr get and set with selinuxMiklos Szeredi2017-07-201-3/+4
| | | | | | | | | | | | | inode_doinit_with_dentry() in SELinux wants to read the upper inode's xattr to get security label, and ovl_xattr_get() calls ovl_dentry_real(), which depends on dentry->d_inode, but d_inode is null and not initialized yet at this point resulting in an Oops. Fix by getting the upperdentry info from the inode directly in this case. Reported-by: Eryu Guan <eguan@redhat.com> Fixes: 09d8b586731b ("ovl: move __upperdentry to ovl_inode") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: fix origin verification of index dirAmir Goldstein2017-07-131-1/+2
| | | | | | | | | | | Commit 54fb347e836f ("ovl: verify index dir matches upper dir") introduced a new ovl_fh flag OVL_FH_FLAG_PATH_UPPER to indicate an upper file handle, but forgot to add the flag to the mask of valid flags, so index dir origin verification always discards existing origin and stores a new one. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: cleanup orphan index entriesAmir Goldstein2017-07-041-0/+3
| | | | | | | | | | | | | | | | | index entry should live only as long as there are upper or lower hardlinks. Cleanup orphan index entries on mount and when dropping the last overlay inode nlink. When about to cleanup or link up to orphan index and the index inode nlink > 1, admit that something went wrong and adjust overlay nlink to index inode nlink - 1 to prevent it from dropping below zero. This could happen when adding lower hardlinks underneath a mounted overlay and then trying to unlink them. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: persistent overlay inode nlink for indexed inodesAmir Goldstein2017-07-041-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With inodes index enabled, an overlay inode nlink counts the union of upper and non-covered lower hardlinks. During the lifetime of a non-pure upper inode, the following nlink modifying operations can happen: 1. Lower hardlink copy up 2. Upper hardlink created, unlinked or renamed over 3. Lower hardlink whiteout or renamed over For the first, copy up case, the union nlink does not change, whether the operation succeeds or fails, but the upper inode nlink may change. Therefore, before copy up, we store the union nlink value relative to the lower inode nlink in the index inode xattr trusted.overlay.nlink. For the second, upper hardlink case, the union nlink should be incremented or decremented IFF the operation succeeds, aligned with nlink change of the upper inode. Therefore, before link/unlink/rename, we store the union nlink value relative to the upper inode nlink in the index inode. For the last, lower cover up case, we simplify things by preceding the whiteout or cover up with copy up. This makes sure that there is an index upper inode where the nlink xattr can be stored before the copied up upper entry is unlink. Return the overlay inode nlinks for indexed upper inodes on stat(2). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: add flag for upper in ovl_entryMiklos Szeredi2017-07-041-0/+2
| | | | | | | | For rename, we need to ensure that an upper alias exists for hard links before attempting the operation. Introduce a flag in ovl_entry to track the state of the upper alias. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: cleanup bad and stale index entries on mountAmir Goldstein2017-07-041-1/+5
| | | | | | | | | | | | | | | | | | | Bad index entries are entries whose name does not match the origin file handle stored in trusted.overlay.origin xattr. Bad index entries could be a result of a system power off in the middle of copy up. Stale index entries are entries whose origin file handle is stale. Stale index entries could be a result of copying layers or removing lower entries while the overlay is not mounted. The case of copying layers should be detected earlier by the verification of upper root dir origin and index dir origin. Both bad and stale index entries are detected and removed on mount. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: lookup index entry for copy up originAmir Goldstein2017-07-041-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When inodes index feature is enabled, lookup in indexdir for the index entry of lower real inode or copy up origin inode. The index entry name is the hex representation of the lower inode file handle. If the index dentry in negative, then either no lower aliases have been copied up yet, or aliases have been copied up in older kernels and are not indexed. If the index dentry for a copy up origin inode is positive, but points to an inode different than the upper inode, then either the upper inode has been copied up and not indexed or it was indexed, but since then index dir was cleared. Either way, that index cannot be used to indentify the overlay inode. If a positive dentry that matches the upper inode was found, then it is safe to use the copy up origin st_ino for upper hardlinks, because all indexed upper hardlinks are represented by the same overlay inode as the copy up origin. Set the INDEX type flag on an indexed upper dentry. A non-upper dentry may also have a positive index from copy up of another lower hardlink. This situation will be handled by following patches. Index lookup is going to be used to prevent breaking hardlinks on copy up. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: verify index dir matches upper dirAmir Goldstein2017-07-041-2/+4
| | | | | | | | | | | | | | | | | | An index dir contains persistent hardlinks to files in upper dir. Therefore, we must never mount an existing index dir with a differnt upper dir. Store the upper root dir file handle in index dir inode when index dir is created and verify the file handle before using an existing index dir on mount. Add an 'is_upper' flag to the overlay file handle encoding and set it when encoding the upper root file handle. This is not critical for index dir verification, but it is good practice towards a standard overlayfs file handle format for NFS export. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: verify upper root dir matches lower root dirAmir Goldstein2017-07-041-0/+3
| | | | | | | | | | | When inodes index feature is enabled, verify that the file handle stored in upper root dir matches the lower root dir or fail to mount. If upper root dir has no stored file handle, encode and store the lower root dir file handle in overlay.origin xattr. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: introduce the inodes index dir featureAmir Goldstein2017-07-041-0/+2
| | | | | | | | | | | | | | | Create the index dir on mount. The index dir will contain hardlinks to upper inodes, named after the hex representation of their origin lower inodes. The index dir is going to be used to prevent breaking lower hardlinks on copy up and to implement overlayfs NFS export. Because the feature is not fully backward compat, enabling the feature is opt-in by config/module/mount option. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* vfs: introduce inode 'inuse' lockAmir Goldstein2017-07-041-0/+2
| | | | | | | | | | | | | | Added an i_state flag I_INUSE and helpers to set/clear/test the bit. The 'inuse' lock is an 'advisory' inode lock, that can be used to extend exclusive create protection beyond parent->i_mutex lock among cooperating users. This is going to be used by overlayfs to get exclusive ownership on upper and work dirs among overlayfs mounts. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: move impure to ovl_inodeMiklos Szeredi2017-07-041-1/+6
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: move __upperdentry to ovl_inodeMiklos Szeredi2017-07-041-5/+7
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: use i_private only as a keyMiklos Szeredi2017-07-041-12/+1
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: simplify getting inodeMiklos Szeredi2017-07-041-3/+2
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* overlayfs: use uuid_t instead of uuid_beChristoph Hellwig2017-06-051-1/+1
| | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
* ovl: mark upper merge dir with type origin entries "impure"Amir Goldstein2017-05-291-4/+11
| | | | | | | | | | | | | | | | | | | | An upper dir is marked "impure" to let ovl_iterate() know that this directory may contain non pure upper entries whose d_ino may need to be read from the origin inode. We already mark a non-merge dir "impure" when moving a non-pure child entry inside it, to let ovl_iterate() know not to iterate the non-merge dir directly. Mark also a merge dir "impure" when moving a non-pure child entry inside it and when copying up a child entry inside it. This can be used to optimize ovl_iterate() to perform a "pure merge" of upper and lower directories, merging the content of the directories, without having to read d_ino from origin inodes. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: mark upper dir with type origin entries "impure"Amir Goldstein2017-05-191-0/+3
| | | | | | | | | | | | | When moving a merge dir or non-dir with copy up origin into a non-merge upper dir (a.k.a pure upper dir), we are marking the target parent dir "impure". ovl_iterate() iterates pure upper dirs directly, because there is no need to filter out whiteouts and merge dir content with lower dir. But for the case of an "impure" upper dir, ovl_iterate() will not be able to iterate the real upper dir directly, because it will need to lookup the origin inode and use it to fill d_ino. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: remove unused arg from ovl_lookup_temp()Miklos Szeredi2017-05-191-1/+1
| | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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