diff options
author | merge <null@invalid> | 2009-01-22 13:55:32 +0000 |
---|---|---|
committer | Andy Green <agreen@octopus.localdomain> | 2009-01-22 13:55:32 +0000 |
commit | aa6f5ffbdba45aa8e19e5048648fc6c7b25376d3 (patch) | |
tree | fbb786d0ac6f8a774fd834e9ce951197e60fbffa /fs/notify/dnotify | |
parent | f2d78193eae5dccd3d588d2c8ea0866efc368332 (diff) |
MERGE-via-pending-tracking-hist-MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141
pending-tracking-hist top was MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 / fdf777a63bcb59e0dfd78bfe2c6242e01f6d4eb9 ... parent commitmessage:
From: merge <null@invalid>
MERGE-via-stable-tracking-hist-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040
stable-tracking-hist top was MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 / 90463bfd2d5a3c8b52f6e6d71024a00e052b0ced ... parent commitmessage:
From: merge <null@invalid>
MERGE-via-mokopatches-tracking-hist-fix-stray-endmenu-patch
mokopatches-tracking-hist top was fix-stray-endmenu-patch / 3630e0be570de8057e7f8d2fe501ed353cdf34e6 ... parent commitmessage:
From: Andy Green <andy@openmoko.com>
fix-stray-endmenu.patch
Signed-off-by: Andy Green <andy@openmoko.com>
Diffstat (limited to 'fs/notify/dnotify')
-rw-r--r-- | fs/notify/dnotify/Kconfig | 10 | ||||
-rw-r--r-- | fs/notify/dnotify/Makefile | 1 | ||||
-rw-r--r-- | fs/notify/dnotify/dnotify.c | 191 |
3 files changed, 202 insertions, 0 deletions
diff --git a/fs/notify/dnotify/Kconfig b/fs/notify/dnotify/Kconfig new file mode 100644 index 00000000000..26adf5dfa64 --- /dev/null +++ b/fs/notify/dnotify/Kconfig @@ -0,0 +1,10 @@ +config DNOTIFY + bool "Dnotify support" + default y + help + Dnotify is a directory-based per-fd file change notification system + that uses signals to communicate events to user-space. There exist + superior alternatives, but some applications may still rely on + dnotify. + + If unsure, say Y. diff --git a/fs/notify/dnotify/Makefile b/fs/notify/dnotify/Makefile new file mode 100644 index 00000000000..f145251dcad --- /dev/null +++ b/fs/notify/dnotify/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_DNOTIFY) += dnotify.o diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c new file mode 100644 index 00000000000..b0aa2cde80b --- /dev/null +++ b/fs/notify/dnotify/dnotify.c @@ -0,0 +1,191 @@ +/* + * Directory notifications for Linux. + * + * Copyright (C) 2000,2001,2002 Stephen Rothwell + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/dnotify.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/fdtable.h> + +int dir_notify_enable __read_mostly = 1; + +static struct kmem_cache *dn_cache __read_mostly; + +static void redo_inode_mask(struct inode *inode) +{ + unsigned long new_mask; + struct dnotify_struct *dn; + + new_mask = 0; + for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next) + new_mask |= dn->dn_mask & ~DN_MULTISHOT; + inode->i_dnotify_mask = new_mask; +} + +void dnotify_flush(struct file *filp, fl_owner_t id) +{ + struct dnotify_struct *dn; + struct dnotify_struct **prev; + struct inode *inode; + + inode = filp->f_path.dentry->d_inode; + if (!S_ISDIR(inode->i_mode)) + return; + spin_lock(&inode->i_lock); + prev = &inode->i_dnotify; + while ((dn = *prev) != NULL) { + if ((dn->dn_owner == id) && (dn->dn_filp == filp)) { + *prev = dn->dn_next; + redo_inode_mask(inode); + kmem_cache_free(dn_cache, dn); + break; + } + prev = &dn->dn_next; + } + spin_unlock(&inode->i_lock); +} + +int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) +{ + struct dnotify_struct *dn; + struct dnotify_struct *odn; + struct dnotify_struct **prev; + struct inode *inode; + fl_owner_t id = current->files; + struct file *f; + int error = 0; + + if ((arg & ~DN_MULTISHOT) == 0) { + dnotify_flush(filp, id); + return 0; + } + if (!dir_notify_enable) + return -EINVAL; + inode = filp->f_path.dentry->d_inode; + if (!S_ISDIR(inode->i_mode)) + return -ENOTDIR; + dn = kmem_cache_alloc(dn_cache, GFP_KERNEL); + if (dn == NULL) + return -ENOMEM; + spin_lock(&inode->i_lock); + prev = &inode->i_dnotify; + while ((odn = *prev) != NULL) { + if ((odn->dn_owner == id) && (odn->dn_filp == filp)) { + odn->dn_fd = fd; + odn->dn_mask |= arg; + inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; + goto out_free; + } + prev = &odn->dn_next; + } + + rcu_read_lock(); + f = fcheck(fd); + rcu_read_unlock(); + /* we'd lost the race with close(), sod off silently */ + /* note that inode->i_lock prevents reordering problems + * between accesses to descriptor table and ->i_dnotify */ + if (f != filp) + goto out_free; + + error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); + if (error) + goto out_free; + + dn->dn_mask = arg; + dn->dn_fd = fd; + dn->dn_filp = filp; + dn->dn_owner = id; + inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; + dn->dn_next = inode->i_dnotify; + inode->i_dnotify = dn; + spin_unlock(&inode->i_lock); + return 0; + +out_free: + spin_unlock(&inode->i_lock); + kmem_cache_free(dn_cache, dn); + return error; +} + +void __inode_dir_notify(struct inode *inode, unsigned long event) +{ + struct dnotify_struct * dn; + struct dnotify_struct **prev; + struct fown_struct * fown; + int changed = 0; + + spin_lock(&inode->i_lock); + prev = &inode->i_dnotify; + while ((dn = *prev) != NULL) { + if ((dn->dn_mask & event) == 0) { + prev = &dn->dn_next; + continue; + } + fown = &dn->dn_filp->f_owner; + send_sigio(fown, dn->dn_fd, POLL_MSG); + if (dn->dn_mask & DN_MULTISHOT) + prev = &dn->dn_next; + else { + *prev = dn->dn_next; + changed = 1; + kmem_cache_free(dn_cache, dn); + } + } + if (changed) + redo_inode_mask(inode); + spin_unlock(&inode->i_lock); +} + +EXPORT_SYMBOL(__inode_dir_notify); + +/* + * This is hopelessly wrong, but unfixable without API changes. At + * least it doesn't oops the kernel... + * + * To safely access ->d_parent we need to keep d_move away from it. Use the + * dentry's d_lock for this. + */ +void dnotify_parent(struct dentry *dentry, unsigned long event) +{ + struct dentry *parent; + + if (!dir_notify_enable) + return; + + spin_lock(&dentry->d_lock); + parent = dentry->d_parent; + if (parent->d_inode->i_dnotify_mask & event) { + dget(parent); + spin_unlock(&dentry->d_lock); + __inode_dir_notify(parent->d_inode, event); + dput(parent); + } else { + spin_unlock(&dentry->d_lock); + } +} +EXPORT_SYMBOL_GPL(dnotify_parent); + +static int __init dnotify_init(void) +{ + dn_cache = kmem_cache_create("dnotify_cache", + sizeof(struct dnotify_struct), 0, SLAB_PANIC, NULL); + return 0; +} + +module_init(dnotify_init) |