diff options
Diffstat (limited to 'fs/tracefs/inode.c')
-rw-r--r-- | fs/tracefs/inode.c | 157 |
1 files changed, 145 insertions, 12 deletions
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 2feb6c58648c..de5b72216b1a 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -21,13 +21,33 @@ #include <linux/parser.h> #include <linux/magic.h> #include <linux/slab.h> +#include "internal.h" #define TRACEFS_DEFAULT_MODE 0700 +static struct kmem_cache *tracefs_inode_cachep __ro_after_init; static struct vfsmount *tracefs_mount; static int tracefs_mount_count; static bool tracefs_registered; +static struct inode *tracefs_alloc_inode(struct super_block *sb) +{ + struct tracefs_inode *ti; + + ti = kmem_cache_alloc(tracefs_inode_cachep, GFP_KERNEL); + if (!ti) + return NULL; + + ti->flags = 0; + + return &ti->vfs_inode; +} + +static void tracefs_free_inode(struct inode *inode) +{ + kmem_cache_free(tracefs_inode_cachep, get_tracefs(inode)); +} + static ssize_t default_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { @@ -127,7 +147,7 @@ static const struct inode_operations tracefs_dir_inode_operations = { .rmdir = tracefs_syscall_rmdir, }; -static struct inode *tracefs_get_inode(struct super_block *sb) +struct inode *tracefs_get_inode(struct super_block *sb) { struct inode *inode = new_inode(sb); if (inode) { @@ -290,6 +310,7 @@ static int tracefs_apply_options(struct super_block *sb, bool remount) struct tracefs_fs_info *fsi = sb->s_fs_info; struct inode *inode = d_inode(sb->s_root); struct tracefs_mount_opts *opts = &fsi->mount_opts; + umode_t tmp_mode; /* * On remount, only reset mode/uid/gid if they were provided as mount @@ -297,8 +318,9 @@ static int tracefs_apply_options(struct super_block *sb, bool remount) */ if (!remount || opts->opts & BIT(Opt_mode)) { - inode->i_mode &= ~S_IALLUGO; - inode->i_mode |= opts->mode; + tmp_mode = READ_ONCE(inode->i_mode) & ~S_IALLUGO; + tmp_mode |= opts->mode; + WRITE_ONCE(inode->i_mode, tmp_mode); } if (!remount || opts->opts & BIT(Opt_uid)) @@ -346,11 +368,31 @@ static int tracefs_show_options(struct seq_file *m, struct dentry *root) } static const struct super_operations tracefs_super_operations = { + .alloc_inode = tracefs_alloc_inode, + .free_inode = tracefs_free_inode, + .drop_inode = generic_delete_inode, .statfs = simple_statfs, .remount_fs = tracefs_remount, .show_options = tracefs_show_options, }; +static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode) +{ + struct tracefs_inode *ti; + + if (!dentry || !inode) + return; + + ti = get_tracefs(inode); + if (ti && ti->flags & TRACEFS_EVENT_INODE) + eventfs_set_ef_status_free(dentry); + iput(inode); +} + +static const struct dentry_operations tracefs_dentry_operations = { + .d_iput = tracefs_dentry_iput, +}; + static int trace_fill_super(struct super_block *sb, void *data, int silent) { static const struct tree_descr trace_files[] = {{""}}; @@ -373,6 +415,7 @@ static int trace_fill_super(struct super_block *sb, void *data, int silent) goto fail; sb->s_op = &tracefs_super_operations; + sb->s_d_op = &tracefs_dentry_operations; tracefs_apply_options(sb, false); @@ -399,7 +442,7 @@ static struct file_system_type trace_fs_type = { }; MODULE_ALIAS_FS("tracefs"); -static struct dentry *start_creating(const char *name, struct dentry *parent) +struct dentry *tracefs_start_creating(const char *name, struct dentry *parent) { struct dentry *dentry; int error; @@ -437,7 +480,7 @@ static struct dentry *start_creating(const char *name, struct dentry *parent) return dentry; } -static struct dentry *failed_creating(struct dentry *dentry) +struct dentry *tracefs_failed_creating(struct dentry *dentry) { inode_unlock(d_inode(dentry->d_parent)); dput(dentry); @@ -445,13 +488,87 @@ static struct dentry *failed_creating(struct dentry *dentry) return NULL; } -static struct dentry *end_creating(struct dentry *dentry) +struct dentry *tracefs_end_creating(struct dentry *dentry) { inode_unlock(d_inode(dentry->d_parent)); return dentry; } /** + * eventfs_start_creating - start the process of creating a dentry + * @name: Name of the file created for the dentry + * @parent: The parent dentry where this dentry will be created + * + * This is a simple helper function for the dynamically created eventfs + * files. When the directory of the eventfs files are accessed, their + * dentries are created on the fly. This function is used to start that + * process. + */ +struct dentry *eventfs_start_creating(const char *name, struct dentry *parent) +{ + struct dentry *dentry; + int error; + + error = simple_pin_fs(&trace_fs_type, &tracefs_mount, + &tracefs_mount_count); + if (error) + return ERR_PTR(error); + + /* + * If the parent is not specified, we create it in the root. + * We need the root dentry to do this, which is in the super + * block. A pointer to that is in the struct vfsmount that we + * have around. + */ + if (!parent) + parent = tracefs_mount->mnt_root; + + if (unlikely(IS_DEADDIR(parent->d_inode))) + dentry = ERR_PTR(-ENOENT); + else + dentry = lookup_one_len(name, parent, strlen(name)); + + if (!IS_ERR(dentry) && dentry->d_inode) { + dput(dentry); + dentry = ERR_PTR(-EEXIST); + } + + if (IS_ERR(dentry)) + simple_release_fs(&tracefs_mount, &tracefs_mount_count); + + return dentry; +} + +/** + * eventfs_failed_creating - clean up a failed eventfs dentry creation + * @dentry: The dentry to clean up + * + * If after calling eventfs_start_creating(), a failure is detected, the + * resources created by eventfs_start_creating() needs to be cleaned up. In + * that case, this function should be called to perform that clean up. + */ +struct dentry *eventfs_failed_creating(struct dentry *dentry) +{ + dput(dentry); + simple_release_fs(&tracefs_mount, &tracefs_mount_count); + return NULL; +} + +/** + * eventfs_end_creating - Finish the process of creating a eventfs dentry + * @dentry: The dentry that has successfully been created. + * + * This function is currently just a place holder to match + * eventfs_start_creating(). In case any synchronization needs to be added, + * this function will be used to implement that without having to modify + * the callers of eventfs_start_creating(). + */ +struct dentry *eventfs_end_creating(struct dentry *dentry) +{ + return dentry; +} + +/** * tracefs_create_file - create a file in the tracefs filesystem * @name: a pointer to a string containing the name of the file to create. * @mode: the permission that the file should have. @@ -490,14 +607,14 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode, if (!(mode & S_IFMT)) mode |= S_IFREG; BUG_ON(!S_ISREG(mode)); - dentry = start_creating(name, parent); + dentry = tracefs_start_creating(name, parent); if (IS_ERR(dentry)) return NULL; inode = tracefs_get_inode(dentry->d_sb); if (unlikely(!inode)) - return failed_creating(dentry); + return tracefs_failed_creating(dentry); inode->i_mode = mode; inode->i_fop = fops ? fops : &tracefs_file_operations; @@ -506,13 +623,13 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode, inode->i_gid = d_inode(dentry->d_parent)->i_gid; d_instantiate(dentry, inode); fsnotify_create(d_inode(dentry->d_parent), dentry); - return end_creating(dentry); + return tracefs_end_creating(dentry); } static struct dentry *__create_dir(const char *name, struct dentry *parent, const struct inode_operations *ops) { - struct dentry *dentry = start_creating(name, parent); + struct dentry *dentry = tracefs_start_creating(name, parent); struct inode *inode; if (IS_ERR(dentry)) @@ -520,7 +637,7 @@ static struct dentry *__create_dir(const char *name, struct dentry *parent, inode = tracefs_get_inode(dentry->d_sb); if (unlikely(!inode)) - return failed_creating(dentry); + return tracefs_failed_creating(dentry); /* Do not set bits for OTH */ inode->i_mode = S_IFDIR | S_IRWXU | S_IRUSR| S_IRGRP | S_IXUSR | S_IXGRP; @@ -534,7 +651,7 @@ static struct dentry *__create_dir(const char *name, struct dentry *parent, d_instantiate(dentry, inode); inc_nlink(d_inode(dentry->d_parent)); fsnotify_mkdir(d_inode(dentry->d_parent), dentry); - return end_creating(dentry); + return tracefs_end_creating(dentry); } /** @@ -628,10 +745,26 @@ bool tracefs_initialized(void) return tracefs_registered; } +static void init_once(void *foo) +{ + struct tracefs_inode *ti = (struct tracefs_inode *) foo; + + inode_init_once(&ti->vfs_inode); +} + static int __init tracefs_init(void) { int retval; + tracefs_inode_cachep = kmem_cache_create("tracefs_inode_cache", + sizeof(struct tracefs_inode), + 0, (SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD| + SLAB_ACCOUNT), + init_once); + if (!tracefs_inode_cachep) + return -ENOMEM; + retval = sysfs_create_mount_point(kernel_kobj, "tracing"); if (retval) return -EINVAL; |