From d9c740d2253e75db8cef8f87a3125c450f3ebd82 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Thu, 28 Jan 2010 11:58:08 +0200 Subject: exofs: Define on-disk per-inode optional layout attribute * Layouts describe the way a file is spread on multiple devices. The layout information is stored in the objects attribute introduced in this patch. * There can be multiple generating function for the layout. Currently defined: - No attribute present - use below moving-window on global device table, all devices. (This is the only one currently used in exofs) - an obj_id generated moving window - the obj_id is a randomizing factor in the otherwise global map layout. - An explicit layout stored, including a data_map and a device index list. - More might be defined in future ... * There are two attributes defined of the same structure: A-data-files-layout - This layout is used by data-files. If present at a directory, all files of that directory will be created with this layout. A-meta-data-layout - This layout is used by a directory and other meta-data information. Also inherited at creation of subdirectories. * At creation time inodes are created with the layout specified above. A usermode utility may change the creation layout on a give directory or file. Which in the case of directories, will also apply to newly created files/subdirectories, children of that directory. In the simple unaltered case of a newly created exofs, no layout attributes are present, and all layouts adhere to the layout specified at the device-table. * In case of a future file system loaded in an old exofs-driver. At iget(), the generating_function is inspected and if not supported will return an IO error to the application and the inode will not be loaded. So not to damage any data. Note: After this patch we do not yet support any type of layout only the RAID0 patch that enables striping at the super-block level will add support for RAID0 layouts above. This way we are past and future compatible and fully bisectable. * Access to the device table is done by an accessor since it will change according to above information. Signed-off-by: Boaz Harrosh --- fs/exofs/ios.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'fs/exofs/ios.c') diff --git a/fs/exofs/ios.c b/fs/exofs/ios.c index 4f679317ca5..2b81f99fd62 100644 --- a/fs/exofs/ios.c +++ b/fs/exofs/ios.c @@ -107,6 +107,19 @@ void exofs_put_io_state(struct exofs_io_state *ios) } } +unsigned exofs_layout_od_id(struct exofs_layout *layout, + osd_id obj_no, unsigned layout_index) +{ + return layout_index; +} + +static inline struct osd_dev *exofs_ios_od(struct exofs_io_state *ios, + unsigned layout_index) +{ + return ios->layout->s_ods[ + exofs_layout_od_id(ios->layout, ios->obj.id, layout_index)]; +} + static void _sync_done(struct exofs_io_state *ios, void *p) { struct completion *waiting = p; @@ -242,7 +255,7 @@ int exofs_sbi_create(struct exofs_io_state *ios) for (i = 0; i < ios->layout->s_numdevs; i++) { struct osd_request *or; - or = osd_start_request(ios->layout->s_ods[i], GFP_KERNEL); + or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL); if (unlikely(!or)) { EXOFS_ERR("%s: osd_start_request failed\n", __func__); ret = -ENOMEM; @@ -266,7 +279,7 @@ int exofs_sbi_remove(struct exofs_io_state *ios) for (i = 0; i < ios->layout->s_numdevs; i++) { struct osd_request *or; - or = osd_start_request(ios->layout->s_ods[i], GFP_KERNEL); + or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL); if (unlikely(!or)) { EXOFS_ERR("%s: osd_start_request failed\n", __func__); ret = -ENOMEM; @@ -290,7 +303,7 @@ int exofs_sbi_write(struct exofs_io_state *ios) for (i = 0; i < ios->layout->s_numdevs; i++) { struct osd_request *or; - or = osd_start_request(ios->layout->s_ods[i], GFP_KERNEL); + or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL); if (unlikely(!or)) { EXOFS_ERR("%s: osd_start_request failed\n", __func__); ret = -ENOMEM; @@ -361,7 +374,7 @@ int exofs_sbi_read(struct exofs_io_state *ios) unsigned first_dev = (unsigned)ios->obj.id; first_dev %= ios->layout->s_numdevs; - or = osd_start_request(ios->layout->s_ods[first_dev], GFP_KERNEL); + or = osd_start_request(exofs_ios_od(ios, first_dev), GFP_KERNEL); if (unlikely(!or)) { EXOFS_ERR("%s: osd_start_request failed\n", __func__); return -ENOMEM; @@ -442,7 +455,7 @@ int exofs_oi_truncate(struct exofs_i_info *oi, u64 size) for (i = 0; i < sbi->layout.s_numdevs; i++) { struct osd_request *or; - or = osd_start_request(sbi->layout.s_ods[i], GFP_KERNEL); + or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL); if (unlikely(!or)) { EXOFS_ERR("%s: osd_start_request failed\n", __func__); ret = -ENOMEM; -- cgit v1.2.3