diff options
| author | Adam D. Moss <c@yotes.com> | 2021-03-16 16:33:34 -0700 |
|---|---|---|
| committer | Tony Hutter <hutter2@llnl.gov> | 2021-06-23 13:22:15 -0700 |
| commit | ac6f3321545a0b82b6b84e7fec6cf62e619d824b (patch) | |
| tree | 92eea47471cefa76c87a36a226f363bf75b90244 | |
| parent | f14b6f23024aaa78fe2c8582f982b88fdcaf8232 (diff) | |
Linux: always check or verify return of igrab()
zhold() wraps igrab() on Linux, and igrab() may fail when the inode
is in the process of being deleted. This means zhold() must only be
called when a reference exists and therefore it cannot be deleted.
This is the case for all existing consumers so add a VERIFY and a
comment explaining this requirement.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Adam Moss <c@yotes.com>
Closes #11704
| -rw-r--r-- | include/os/linux/zfs/sys/zfs_znode_impl.h | 8 | ||||
| -rw-r--r-- | module/os/linux/zfs/zfs_ctldir.c | 3 | ||||
| -rw-r--r-- | module/os/linux/zfs/zfs_vfsops.c | 6 | ||||
| -rw-r--r-- | module/os/linux/zfs/zpl_inode.c | 3 |
4 files changed, 16 insertions, 4 deletions
diff --git a/include/os/linux/zfs/sys/zfs_znode_impl.h b/include/os/linux/zfs/sys/zfs_znode_impl.h index f17b8eb67..79049df69 100644 --- a/include/os/linux/zfs/sys/zfs_znode_impl.h +++ b/include/os/linux/zfs/sys/zfs_znode_impl.h @@ -73,7 +73,13 @@ extern "C" { #define zn_has_cached_data(zp) ((zp)->z_is_mapped) #define zn_rlimit_fsize(zp, uio, td) (0) -#define zhold(zp) igrab(ZTOI((zp))) +/* + * zhold() wraps igrab() on Linux, and igrab() may fail when the + * inode is in the process of being deleted. As zhold() must only be + * called when a ref already exists - so the inode cannot be + * mid-deletion - we VERIFY() this. + */ +#define zhold(zp) VERIFY3P(igrab(ZTOI((zp))), !=, NULL) #define zrele(zp) iput(ZTOI((zp))) /* Called on entry to each ZFS inode and vfs operation. */ diff --git a/module/os/linux/zfs/zfs_ctldir.c b/module/os/linux/zfs/zfs_ctldir.c index a1668e46e..d33188f38 100644 --- a/module/os/linux/zfs/zfs_ctldir.c +++ b/module/os/linux/zfs/zfs_ctldir.c @@ -590,7 +590,8 @@ struct inode * zfsctl_root(znode_t *zp) { ASSERT(zfs_has_ctldir(zp)); - igrab(ZTOZSB(zp)->z_ctldir); + /* Must have an existing ref, so igrab() cannot return NULL */ + VERIFY3P(igrab(ZTOZSB(zp)->z_ctldir), !=, NULL); return (ZTOZSB(zp)->z_ctldir); } diff --git a/module/os/linux/zfs/zfs_vfsops.c b/module/os/linux/zfs/zfs_vfsops.c index 165c1218a..44f575d8a 100644 --- a/module/os/linux/zfs/zfs_vfsops.c +++ b/module/os/linux/zfs/zfs_vfsops.c @@ -1734,7 +1734,11 @@ zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp) VERIFY(zfsctl_root_lookup(*ipp, "snapshot", ipp, 0, kcred, NULL, NULL) == 0); } else { - igrab(*ipp); + /* + * Must have an existing ref, so igrab() + * cannot return NULL + */ + VERIFY3P(igrab(*ipp), !=, NULL); } ZFS_EXIT(zfsvfs); return (0); diff --git a/module/os/linux/zfs/zpl_inode.c b/module/os/linux/zfs/zpl_inode.c index ab0373ef9..bd1f60516 100644 --- a/module/os/linux/zfs/zpl_inode.c +++ b/module/os/linux/zfs/zpl_inode.c @@ -639,7 +639,8 @@ zpl_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) crhold(cr); ip->i_ctime = current_time(ip); - igrab(ip); /* Use ihold() if available */ + /* Must have an existing ref, so igrab() cannot return NULL */ + VERIFY3P(igrab(ip), !=, NULL); cookie = spl_fstrans_mark(); error = -zfs_link(ITOZ(dir), ITOZ(ip), dname(dentry), cr, 0); |