- 05 2月, 2018 1 次提交
-
-
由 Amir Goldstein 提交于
Another fix for an issue reported by 0-day robot. Reported-by: NDan Carpenter <dan.carpenter@oracle.com> Fixes: 8ed5eec9 ("ovl: encode pure upper file handles") Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
- 24 1月, 2018 13 次提交
-
-
由 Amir Goldstein 提交于
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: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
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: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
Similar to decoding a pure upper dir file handle, decoding a pure lower dir file handle is implemented by looking an overlay dentry of the same path as the pure lower path and verifying that the overlay dentry's real lower matches the decoded real lower file handle. Unlike the case of upper dir file handle, the lookup of overlay path by lower real path can fail or find a mismatched overlay dentry if any of the lower parents have been copied up and renamed. To address this case we will need to check if any of the lower parents are indexed. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
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: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
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: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
Decoding an indexed non-dir file handle is similar to decoding a lower non-dir file handle, but additionally, we lookup the file handle in index dir by name to find the real upper inode. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
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: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
For indexed or lower non-dir, encode a non-connectable lower file handle from origin inode. For indexed or lower dir, when ofs->numlower == 1, encode a lower file handle from lower dir. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
Decoding a merge dir, whose origin's parent is under a redirected lower dir is not always possible. As a simple aproximation, we do not encode lower dir file handles when overlay has multiple lower layers and origin is below the topmost lower layer. We should later relax this condition and copy up only the parent that is under a redirected lower. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
We only need to encode origin if there is a chance that the same object was encoded pre copy up and then we need to stay consistent with the same encoding also after copy up. In case a non-pure upper is not indexed, then it was copied up before NFS export support was enabled. In that case, we don't need to worry about staying consistent with pre copy up encoding and we encode an upper file handle. This mitigates the problem that with no index, we cannot find an upper inode from origin inode, so we cannot decode a non-indexed upper from origin file handle. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
Until this change, we decoded upper file handles by instantiating an overlay dentry from the real upper dentry. This is sufficient to handle pure upper files, but insufficient to handle merge/impure dirs. To that end, if decoded real upper dir is connected and hashed, we lookup an overlay dentry with the same path as the real upper dir. If decoded real upper is non-dir, we instantiate a disconnected overlay dentry as before this change. Because ovl_fh_to_dentry() returns a connected overlay dir dentry, exportfs never needs to call get_parent() and get_name() to reconnect an upper overlay dir. Because connectable non-dir file handles are not supported, exportfs will not be able to use fh_to_parent() and get_name() methods to reconnect a disconnected non-dir to its parent. Therefore, the methods get_parent() and get_name() are implemented just to print out a sanity warning and the method fh_to_parent() is implemented to warn the user that using the 'subtree_check' exportfs option is not supported. An alternative approach could have been to implement instantiating of an overlay directory inode from origin/index and implement get_parent() and get_name() by calling into underlying fs operations and them instantiating the overlay parent dir. The reasons for not choosing the get_parent() approach were: - Obtaining a disconnected overlay dir dentry would requires a delicate re-factoring of ovl_lookup() to get a dentry with overlay parent info. It was preferred to avoid doing that re-factoring unless it was proven worthy. - Going down the path of disconnected dir would mean that the (non trivial) code path of d_splice_alias() could be traveled and that meant writing more tests and introduces race cases that are very hard to hit on purpose. Taking the path of connecting overlay dentry by forward lookup is therefore the safe and boring way to avoid surprises. The culprits of the chosen "connected overlay dentry" approach: - We need to take special care to rename of ancestors while connecting the overlay dentry by real dentry path. These subtleties are usually handled by generic exportfs and VFS code. - In a hypothetical workload, we could end up in a loop trying to connect, interrupted by rename and restarting connect forever. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
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: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-
由 Amir Goldstein 提交于
Encode overlay file handles as struct ovl_fh containing the file handle encoding of the real upper inode. Signed-off-by: NAmir Goldstein <amir73il@gmail.com> Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
-