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authorDave Chinner <david@fromorbit.com>2015-02-23 21:19:28 +1100
committerDave Chinner <david@fromorbit.com>2015-02-23 21:19:28 +1100
commit501ab32387533924b211cacff36d19296414ec0b (patch)
tree47f131ce9bc31ae20949706a18d351b68944e581 /fs/xfs/xfs_mount.h
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
downloadlinux-501ab32387533924b211cacff36d19296414ec0b.tar.bz2
xfs: use generic percpu counters for inode counter
XFS has hand-rolled per-cpu counters for the superblock since before there was any generic implementation. There are some warts around the use of them for the inode counter as the hand rolled counter is designed to be accurate at zero, but has no specific accurracy at any other value. This design causes problems for the maximum inode count threshold enforcement, as there is no trigger that balances the counters as they get close tothe maximum threshold. Instead of designing new triggers for balancing, just replace the handrolled per-cpu counter with a generic counter. This enables us to update the counter through the normal superblock modification funtions, but rather than do that we add a xfs_mod_icount() helper function (from Christoph Hellwig) and keep the percpu counter outside the superblock in the struct xfs_mount. This means we still need to initialise the per-cpu counter specifically when we read the superblock, and vice versa when we log/write it, but it does mean that we don't need to change any other code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_mount.h')
-rw-r--r--fs/xfs/xfs_mount.h7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 0d8abd6364d9..76b18c8c58c5 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -41,7 +41,6 @@ struct xfs_da_geometry;
typedef struct xfs_icsb_cnts {
uint64_t icsb_fdblocks;
uint64_t icsb_ifree;
- uint64_t icsb_icount;
unsigned long icsb_flags;
} xfs_icsb_cnts_t;
@@ -81,8 +80,11 @@ typedef struct xfs_mount {
struct super_block *m_super;
xfs_tid_t m_tid; /* next unused tid for fs */
struct xfs_ail *m_ail; /* fs active log item list */
- xfs_sb_t m_sb; /* copy of fs superblock */
+
+ struct xfs_sb m_sb; /* copy of fs superblock */
spinlock_t m_sb_lock; /* sb counter lock */
+ struct percpu_counter m_icount; /* allocated inodes counter */
+
struct xfs_buf *m_sb_bp; /* buffer for superblock */
char *m_fsname; /* filesystem name */
int m_fsname_len; /* strlen of fs name */
@@ -388,6 +390,7 @@ extern void xfs_unmountfs(xfs_mount_t *);
extern int xfs_mod_incore_sb(xfs_mount_t *, xfs_sb_field_t, int64_t, int);
extern int xfs_mod_incore_sb_batch(xfs_mount_t *, xfs_mod_sb_t *,
uint, int);
+extern int xfs_mod_icount(struct xfs_mount *mp, int64_t delta);
extern int xfs_mount_log_sb(xfs_mount_t *);
extern struct xfs_buf *xfs_getsb(xfs_mount_t *, int);
extern int xfs_readsb(xfs_mount_t *, int);