diff options
Diffstat (limited to 'fs/jbd2/journal.c')
| -rw-r--r-- | fs/jbd2/journal.c | 77 |
1 files changed, 73 insertions, 4 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 58144102bf2..18bfd5dab64 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -38,6 +38,10 @@ #include <linux/debugfs.h> #include <linux/seq_file.h> #include <linux/math64.h> +#include <linux/hash.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/jbd2.h> #include <asm/uaccess.h> #include <asm/page.h> @@ -1781,7 +1785,7 @@ int jbd2_journal_wipe(journal_t *journal, int write) * Journal abort has very specific semantics, which we describe * for journal abort. * - * Two internal function, which provide abort to te jbd layer + * Two internal functions, which provide abort to the jbd layer * itself are here. */ @@ -1879,7 +1883,7 @@ void jbd2_journal_abort(journal_t *journal, int errno) * int jbd2_journal_errno () - returns the journal's error state. * @journal: journal to examine. * - * This is the errno numbet set with jbd2_journal_abort(), the last + * This is the errno number set with jbd2_journal_abort(), the last * time the journal was mounted - if the journal was stopped * without calling abort this will be 0. * @@ -1903,7 +1907,7 @@ int jbd2_journal_errno(journal_t *journal) * int jbd2_journal_clear_err () - clears the journal's error state * @journal: journal to act on. * - * An error must be cleared or Acked to take a FS out of readonly + * An error must be cleared or acked to take a FS out of readonly * mode. */ int jbd2_journal_clear_err(journal_t *journal) @@ -1923,7 +1927,7 @@ int jbd2_journal_clear_err(journal_t *journal) * void jbd2_journal_ack_err() - Ack journal err. * @journal: journal to act on. * - * An error must be cleared or Acked to take a FS out of readonly + * An error must be cleared or acked to take a FS out of readonly * mode. */ void jbd2_journal_ack_err(journal_t *journal) @@ -2377,6 +2381,71 @@ static void __exit journal_exit(void) jbd2_journal_destroy_caches(); } +/* + * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 + * tracing infrastructure to map a dev_t to a device name. + * + * The caller should use rcu_read_lock() in order to make sure the + * device name stays valid until its done with it. We use + * rcu_read_lock() as well to make sure we're safe in case the caller + * gets sloppy, and because rcu_read_lock() is cheap and can be safely + * nested. + */ +struct devname_cache { + struct rcu_head rcu; + dev_t device; + char devname[BDEVNAME_SIZE]; +}; +#define CACHE_SIZE_BITS 6 +static struct devname_cache *devcache[1 << CACHE_SIZE_BITS]; +static DEFINE_SPINLOCK(devname_cache_lock); + +static void free_devcache(struct rcu_head *rcu) +{ + kfree(rcu); +} + +const char *jbd2_dev_to_name(dev_t device) +{ + int i = hash_32(device, CACHE_SIZE_BITS); + char *ret; + struct block_device *bd; + + rcu_read_lock(); + if (devcache[i] && devcache[i]->device == device) { + ret = devcache[i]->devname; + rcu_read_unlock(); + return ret; + } + rcu_read_unlock(); + + spin_lock(&devname_cache_lock); + if (devcache[i]) { + if (devcache[i]->device == device) { + ret = devcache[i]->devname; + spin_unlock(&devname_cache_lock); + return ret; + } + call_rcu(&devcache[i]->rcu, free_devcache); + } + devcache[i] = kmalloc(sizeof(struct devname_cache), GFP_KERNEL); + if (!devcache[i]) { + spin_unlock(&devname_cache_lock); + return "NODEV-ALLOCFAILURE"; /* Something non-NULL */ + } + devcache[i]->device = device; + bd = bdget(device); + if (bd) { + bdevname(bd, devcache[i]->devname); + bdput(bd); + } else + __bdevname(device, devcache[i]->devname); + ret = devcache[i]->devname; + spin_unlock(&devname_cache_lock); + return ret; +} +EXPORT_SYMBOL(jbd2_dev_to_name); + MODULE_LICENSE("GPL"); module_init(journal_init); module_exit(journal_exit); |