Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
NFS: Avoid changing nlink when file removes and attribute updates race
If a file removal races with another operation that updates its
attributes, then skip the change to nlink, and just mark the attributes
as being stale.
Reported-by: Aiden Lambert <alambert48@gatech.edu>
Fixes: 59a707b0d42e ("NFS: Ensure we revalidate the inode correctly after remove or rename")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
+13
-6
+13
-6
fs/nfs/dir.c
+13
-6
fs/nfs/dir.c
···
1894
1894
}
1895
1895
1896
1896
/* Ensure that we revalidate inode->i_nlink */
1897
-
static void nfs_drop_nlink(struct inode *inode)
1897
+
static void nfs_drop_nlink(struct inode *inode, unsigned long gencount)
1898
1898
{
1899
+
struct nfs_inode *nfsi = NFS_I(inode);
1900
+
1899
1901
spin_lock(&inode->i_lock);
1900
1902
/* drop the inode if we're reasonably sure this is the last link */
1901
-
if (inode->i_nlink > 0)
1903
+
if (inode->i_nlink > 0 && gencount == nfsi->attr_gencount)
1902
1904
drop_nlink(inode);
1903
-
NFS_I(inode)->attr_gencount = nfs_inc_attr_generation_counter();
1905
+
nfsi->attr_gencount = nfs_inc_attr_generation_counter();
1904
1906
nfs_set_cache_invalid(
1905
1907
inode, NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME |
1906
1908
NFS_INO_INVALID_NLINK);
···
1916
1914
static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
1917
1915
{
1918
1916
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
1917
+
unsigned long gencount = READ_ONCE(NFS_I(inode)->attr_gencount);
1919
1918
nfs_complete_unlink(dentry, inode);
1920
-
nfs_drop_nlink(inode);
1919
+
nfs_drop_nlink(inode, gencount);
1921
1920
}
1922
1921
iput(inode);
1923
1922
}
···
2510
2507
2511
2508
trace_nfs_remove_enter(dir, dentry);
2512
2509
if (inode != NULL) {
2510
+
unsigned long gencount = READ_ONCE(NFS_I(inode)->attr_gencount);
2511
+
2513
2512
error = NFS_PROTO(dir)->remove(dir, dentry);
2514
2513
if (error == 0)
2515
-
nfs_drop_nlink(inode);
2514
+
nfs_drop_nlink(inode, gencount);
2516
2515
} else
2517
2516
error = NFS_PROTO(dir)->remove(dir, dentry);
2518
2517
if (error == -ENOENT)
···
2714
2709
{
2715
2710
struct inode *old_inode = d_inode(old_dentry);
2716
2711
struct inode *new_inode = d_inode(new_dentry);
2712
+
unsigned long new_gencount = 0;
2717
2713
struct dentry *dentry = NULL;
2718
2714
struct rpc_task *task;
2719
2715
bool must_unblock = false;
···
2767
2761
} else {
2768
2762
block_revalidate(new_dentry);
2769
2763
must_unblock = true;
2764
+
new_gencount = NFS_I(new_inode)->attr_gencount;
2770
2765
spin_unlock(&new_dentry->d_lock);
2771
2766
}
2772
2767
···
2807
2800
new_dir, new_dentry, error);
2808
2801
if (!error) {
2809
2802
if (new_inode != NULL)
2810
-
nfs_drop_nlink(new_inode);
2803
+
nfs_drop_nlink(new_inode, new_gencount);
2811
2804
/*
2812
2805
* The d_move() should be here instead of in an async RPC completion
2813
2806
* handler because we need the proper locks to move the dentry. If