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author | Amir Goldstein <amir73il@gmail.com> | 2023-04-23 19:02:04 +0300 |
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committer | Amir Goldstein <amir73il@gmail.com> | 2023-08-12 19:02:47 +0300 |
commit | 16aac5ad1fa94894b798dd522c5c3a6a0628d7f0 (patch) | |
tree | 292889602a225cba9ad4399c6d9f63a5e14e04d5 /fs/overlayfs/export.c | |
parent | 0c71faf5a607c8744ccee702846970bdb1a8005f (diff) | |
download | linux-16aac5ad1fa94894b798dd522c5c3a6a0628d7f0.tar.xz |
ovl: support encoding non-decodable file handles
When all layers support file handles, we support encoding non-decodable
file handles (a.k.a. fid) even with nfs_export=off.
When file handles do not need to be decoded, we do not need to copy up
redirected lower directories on encode, and we encode also non-indexed
upper with lower file handle, so fid will not change on copy up.
This enables reporting fanotify events with file handles on overlayfs
with default config/mount options.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Diffstat (limited to 'fs/overlayfs/export.c')
-rw-r--r-- | fs/overlayfs/export.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 35680b6e175b..6d54f3fc24c5 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -174,28 +174,37 @@ static int ovl_connect_layer(struct dentry *dentry) * U = upper file handle * L = lower file handle * - * (*) Connecting an overlay dir from real lower dentry is not always + * (*) Decoding a connected overlay dir from real lower dentry is not always * possible when there are redirects in lower layers and non-indexed merge dirs. * To mitigate those case, we may copy up the lower dir ancestor before encode - * a lower dir file handle. + * of a decodable file handle for non-upper dir. * * Return 0 for upper file handle, > 0 for lower file handle or < 0 on error. */ static int ovl_check_encode_origin(struct dentry *dentry) { struct ovl_fs *ofs = dentry->d_sb->s_fs_info; + bool decodable = ofs->config.nfs_export; + + /* Lower file handle for non-upper non-decodable */ + if (!ovl_dentry_upper(dentry) && !decodable) + return 0; /* Upper file handle for pure upper */ if (!ovl_dentry_lower(dentry)) return 0; /* - * Upper file handle for non-indexed upper. - * * Root is never indexed, so if there's an upper layer, encode upper for * root. */ - if (ovl_dentry_upper(dentry) && + if (dentry == dentry->d_sb->s_root) + return 0; + + /* + * Upper decodable file handle for non-indexed upper. + */ + if (ovl_dentry_upper(dentry) && decodable && !ovl_test_flag(OVL_INDEX, d_inode(dentry))) return 0; @@ -205,7 +214,7 @@ static int ovl_check_encode_origin(struct dentry *dentry) * ovl_connect_layer() will try to make origin's layer "connected" by * copying up a "connectable" ancestor. */ - if (d_is_dir(dentry) && ovl_upper_mnt(ofs)) + if (d_is_dir(dentry) && ovl_upper_mnt(ofs) && decodable) return ovl_connect_layer(dentry); /* Lower file handle for indexed and non-upper dir/non-dir */ @@ -876,3 +885,8 @@ const struct export_operations ovl_export_operations = { .get_name = ovl_get_name, .get_parent = ovl_get_parent, }; + +/* encode_fh() encodes non-decodable file handles with nfs_export=off */ +const struct export_operations ovl_export_fid_operations = { + .encode_fh = ovl_encode_fh, +}; |