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author | 2018-01-17 14:40:27 +0200 | |
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committer | 2018-01-24 11:26:05 +0100 | |
commit | 061701540349c30d72e48a201449a840c77ad509 (patch) | |
tree | 46d3e9191ba287cd420af0a41bd5aba86bb50a89 /fs/overlayfs/export.c | |
parent | ovl: lookup connected ancestor of dir in inode cache (diff) | |
download | linux-061701540349c30d72e48a201449a840c77ad509.tar.gz linux-061701540349c30d72e48a201449a840c77ad509.tar.bz2 linux-061701540349c30d72e48a201449a840c77ad509.zip |
ovl: lookup indexed ancestor of lower dir
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>
Diffstat (limited to 'fs/overlayfs/export.c')
-rw-r--r-- | fs/overlayfs/export.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 092e6e8c9258..b65ea49de457 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -294,6 +294,10 @@ fail: goto out; } +static struct dentry *ovl_lookup_real(struct super_block *sb, + struct dentry *real, + struct ovl_layer *layer); + /* * Lookup an indexed or hashed overlay dentry by real inode. */ @@ -301,9 +305,16 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb, struct dentry *real, struct ovl_layer *layer) { + struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_layer upper_layer = { .mnt = ofs->upper_mnt }; + struct dentry *index = NULL; struct dentry *this = NULL; struct inode *inode; + /* + * Decoding upper dir from index is expensive, so first try to lookup + * overlay dentry in inode/dcache. + */ inode = ovl_lookup_inode(sb, real, !layer->idx); if (IS_ERR(inode)) return ERR_CAST(inode); @@ -312,7 +323,35 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb, iput(inode); } - /* TODO: use index when looking up by origin inode */ + /* + * For decoded lower dir file handle, lookup index by origin to check + * if lower dir was copied up and and/or removed. + */ + if (!this && layer->idx && ofs->indexdir && !WARN_ON(!d_is_dir(real))) { + index = ovl_lookup_index(ofs, NULL, real, false); + if (IS_ERR(index)) + return index; + } + + /* Get connected upper overlay dir from index */ + if (index) { + struct dentry *upper = ovl_index_upper(ofs, index); + + dput(index); + if (IS_ERR_OR_NULL(upper)) + return upper; + + /* + * ovl_lookup_real() in lower layer may call recursively once to + * ovl_lookup_real() in upper layer. The first level call walks + * back lower parents to the topmost indexed parent. The second + * recursive call walks back from indexed upper to the topmost + * connected/hashed upper parent (or up to root). + */ + this = ovl_lookup_real(sb, upper, &upper_layer); + dput(upper); + } + if (!this) return NULL; |