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author | Amir Goldstein <amir73il@gmail.com> | 2018-03-16 00:39:01 +0300 |
---|---|---|
committer | Miklos Szeredi <mszeredi@redhat.com> | 2018-04-12 13:04:48 +0300 |
commit | 695b46e76b62447e506cddc87e088236498008e5 (patch) | |
tree | 522f7a910302f5879915ebb19352632c4fdc1a5f /fs/overlayfs/inode.c | |
parent | 3eb2ce825ea1ad89d20f7a3b5780df850e4be274 (diff) | |
download | linux-695b46e76b62447e506cddc87e088236498008e5.tar.xz |
ovl: set i_ino to the value of st_ino for NFS export
Eddie Horng reported that readdir of an overlayfs directory that
was exported via NFSv3 returns entries with d_type set to DT_UNKNOWN.
The reason is that while preparing the response for readdirplus, nfsd
checks inside encode_entryplus_baggage() that a child dentry's inode
number matches the value of d_ino returns by overlayfs readdir iterator.
Because the overlayfs inodes use arbitrary inode numbers that are not
correlated with the values of st_ino/d_ino, NFSv3 falls back to not
encoding d_type. Although this is an allowed behavior, we can fix it for
the case of all overlayfs layers on the same underlying filesystem.
When NFS export is enabled and d_ino is consistent with st_ino
(samefs), set the same value also to i_ino in ovl_fill_inode() for all
overlayfs inodes, nfsd readdirplus sanity checks will pass.
ovl_fill_inode() may be called from ovl_new_inode(), before real inode
was created with ino arg 0. In that case, i_ino will be updated to real
upper inode i_ino on ovl_inode_init() or ovl_inode_update().
Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
Tested-by: Eddie Horng <eddiehorng.tw@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Fixes: 8383f1748829 ("ovl: wire up NFS export operations")
Cc: <stable@vger.kernel.org> #v4.16
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/inode.c')
-rw-r--r-- | fs/overlayfs/inode.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 3b1bd469accd..4689716f23d8 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -459,9 +459,20 @@ static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode) #endif } -static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev) +static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev, + unsigned long ino) { - inode->i_ino = get_next_ino(); + /* + * When NFS export is enabled and d_ino is consistent with st_ino + * (samefs), set the same value to i_ino, because nfsd readdirplus + * compares d_ino values to i_ino values of child entries. When called + * from ovl_new_inode(), ino arg is 0, so i_ino will be updated to real + * upper inode i_ino on ovl_inode_init() or ovl_inode_update(). + */ + if (inode->i_sb->s_export_op && ovl_same_sb(inode->i_sb)) + inode->i_ino = ino; + else + inode->i_ino = get_next_ino(); inode->i_mode = mode; inode->i_flags |= S_NOCMTIME; #ifdef CONFIG_FS_POSIX_ACL @@ -597,7 +608,7 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev) inode = new_inode(sb); if (inode) - ovl_fill_inode(inode, mode, rdev); + ovl_fill_inode(inode, mode, rdev, 0); return inode; } @@ -710,6 +721,7 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, struct inode *inode; bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index); bool is_dir; + unsigned long ino = 0; if (!realinode) realinode = d_inode(lowerdentry); @@ -748,13 +760,14 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, if (!is_dir) nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink); set_nlink(inode, nlink); + ino = key->i_ino; } else { /* Lower hardlink that will be broken on copy up */ inode = new_inode(sb); if (!inode) goto out_nomem; } - ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev); + ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino); ovl_inode_init(inode, upperdentry, lowerdentry); if (upperdentry && ovl_is_impuredir(upperdentry)) |