diff options
| author | David Chinner <dgc@sgi.com> | 2005-11-02 10:33:05 +1100 |
|---|---|---|
| committer | Nathan Scott <nathans@sgi.com> | 2005-11-02 10:33:05 +1100 |
| commit | e8c8b3a79d85c22d3665b97dde843dc4d8d7ae37 (patch) | |
| tree | a82b58ebc5c40474cdc53c91bd135b97034de565 /fs/xfs/xfs_mount.h | |
| parent | ee34807a65aa0c5911dc27682863afca780a003e (diff) | |
[XFS] Introduce two new mount options (nolargeio/largeio) to allow
filesystems to expose the filesystem stripe width in stat(2) rather than
the page cache size. This allows applications requiring high bandwidth to
easily determine the optimum I/O size for the underlying filesystem. The
default is to report the page cache size (i.e. "nolargeio").
SGI-PV: 942818
SGI-Modid: xfs-linux:xfs-kern:23830a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_mount.h')
| -rw-r--r-- | fs/xfs/xfs_mount.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 0653beecf93..b71af184aea 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -421,6 +421,9 @@ typedef struct xfs_mount { * allocation */ #define XFS_MOUNT_IHASHSIZE 0x00100000 /* inode hash table size */ #define XFS_MOUNT_DIRSYNC 0x00200000 /* synchronous directory ops */ +#define XFS_MOUNT_COMPAT_IOSIZE 0x00400000 /* don't report large preferred + * I/O size in stat() */ + /* * Default minimum read and write sizes. @@ -442,6 +445,30 @@ typedef struct xfs_mount { #define XFS_WSYNC_READIO_LOG 15 /* 32K */ #define XFS_WSYNC_WRITEIO_LOG 14 /* 16K */ +/* + * Allow large block sizes to be reported to userspace programs if the + * "largeio" mount option is used. + * + * If compatibility mode is specified, simply return the basic unit of caching + * so that we don't get inefficient read/modify/write I/O from user apps. + * Otherwise.... + * + * If the underlying volume is a stripe, then return the stripe width in bytes + * as the recommended I/O size. It is not a stripe and we've set a default + * buffered I/O size, return that, otherwise return the compat default. + */ +static inline unsigned long +xfs_preferred_iosize(xfs_mount_t *mp) +{ + if (mp->m_flags & XFS_MOUNT_COMPAT_IOSIZE) + return PAGE_CACHE_SIZE; + return (mp->m_swidth ? + (mp->m_swidth << mp->m_sb.sb_blocklog) : + ((mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) ? + (1 << (int)MAX(mp->m_readio_log, mp->m_writeio_log)) : + PAGE_CACHE_SIZE)); +} + #define XFS_MAXIOFFSET(mp) ((mp)->m_maxioffset) #define XFS_FORCED_SHUTDOWN(mp) ((mp)->m_flags & XFS_MOUNT_FS_SHUTDOWN) |