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autofs: don't bother with atomics for ino->count

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All writers are serialized on inode->i_rwsem.  So are the readers
outside of expire.c.  And the readers in expire.c are in the
code that really doesn't care about narrow races - it's looking
for expiry candidates and its callers have to cope with the
possibility of a good candidate becoming busy right under them.

No point bothering with atomic operations - just use int and
mark the non-serialized readers with READ_ONCE().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2019-09-17 23:31:27 -04:00
parent c3aed16680
commit 850d71acd5
3 changed files with 14 additions and 14 deletions
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20
fs/autofs/root.c
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@@ -569,9 +569,9 @@ static int autofs_dir_symlink(struct inode *dir,
d_add(dentry, inode);
dget(dentry);
atomic_inc(&ino->count);
ino->count++;
p_ino = autofs_dentry_ino(dentry->d_parent);
atomic_inc(&p_ino->count);
p_ino->count++;
dir->i_mtime = current_time(dir);
@@ -609,9 +609,9 @@ static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry)
if (sbi->flags & AUTOFS_SBI_CATATONIC)
return -EACCES;
atomic_dec(&ino->count);
ino->count--;
p_ino = autofs_dentry_ino(dentry->d_parent);
atomic_dec(&p_ino->count);
p_ino->count--;
dput(ino->dentry);
d_inode(dentry)->i_size = 0;
@@ -669,7 +669,7 @@ static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
/* only consider parents below dentrys in the root */
if (IS_ROOT(parent->d_parent))
return;
if (atomic_read(&autofs_dentry_ino(parent)->count) == 2)
if (autofs_dentry_ino(parent)->count == 2)
managed_dentry_set_managed(parent);
}
@@ -691,7 +691,7 @@ static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry)
if (sbi->flags & AUTOFS_SBI_CATATONIC)
return -EACCES;
if (atomic_read(&ino->count) != 1)
if (ino->count != 1)
return -ENOTEMPTY;
spin_lock(&sbi->lookup_lock);
@@ -702,9 +702,9 @@ static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry)
if (sbi->version < 5)
autofs_clear_leaf_automount_flags(dentry);
atomic_dec(&ino->count);
ino->count--;
p_ino = autofs_dentry_ino(dentry->d_parent);
atomic_dec(&p_ino->count);
p_ino->count--;
dput(ino->dentry);
d_inode(dentry)->i_size = 0;
clear_nlink(d_inode(dentry));
@@ -750,9 +750,9 @@ static int autofs_dir_mkdir(struct inode *dir,
autofs_set_leaf_automount_flags(dentry);
dget(dentry);
atomic_inc(&ino->count);
ino->count++;
p_ino = autofs_dentry_ino(dentry->d_parent);
atomic_inc(&p_ino->count);
p_ino->count++;
inc_nlink(dir);
dir->i_mtime = current_time(dir);