diff options
| -rw-r--r-- | fs/ubifs/budget.c | 45 | ||||
| -rw-r--r-- | fs/ubifs/misc.h | 32 | ||||
| -rw-r--r-- | fs/ubifs/ubifs.h | 1 |
3 files changed, 46 insertions, 32 deletions
diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c index 9ef630a594c..7851480a6ce 100644 --- a/fs/ubifs/budget.c +++ b/fs/ubifs/budget.c @@ -702,6 +702,51 @@ void ubifs_release_dirty_inode_budget(struct ubifs_info *c, } /** + * ubifs_reported_space - calculate reported free space. + * @c: the UBIFS file-system description object + * @free: amount of free space + * + * This function calculates amount of free space which will be reported to + * user-space. User-space application tend to expect that if the file-system + * (e.g., via the 'statfs()' call) reports that it has N bytes available, they + * are able to write a file of size N. UBIFS attaches node headers to each data + * node and it has to write indexind nodes as well. This introduces additional + * overhead, and UBIFS it has to report sligtly less free space to meet the + * above expectetion. + * + * This function assumes free space is made up of uncompressed data nodes and + * full index nodes (one per data node, tripled because we always allow enough + * space to write the index thrice). + * + * Note, the calculation is pessimistic, which means that most of the time + * UBIFS reports less space than it actually has. + */ +long long ubifs_reported_space(const struct ubifs_info *c, uint64_t free) +{ + int divisor, factor; + + /* + * Reported space size is @free * X, where X is UBIFS block size + * divided by UBIFS block size + all overhead one data block + * introduces. The overhead is the node header + indexing overhead. + * + * Indexing overhead is calculations are based on the following + * formula: I = N/(f - 1) + 1, where I - number of indexing nodes, N - + * number of data nodes, f - fanout. Because effective UBIFS fanout is + * twice as less than maximum fanout, we assume that each data node + * introduces 3 * @c->max_idx_node_sz / (@c->fanout/2 - 1) bytes. + * Note, the multiplier 3 is because UBIFS reseves thrice as more space + * for the index. + */ + factor = UBIFS_BLOCK_SIZE; + divisor = UBIFS_MAX_DATA_NODE_SZ; + divisor += (c->max_idx_node_sz * 3) / ((c->fanout >> 1) - 1); + free *= factor; + do_div(free, divisor); + return free; +} + +/** * ubifs_budg_get_free_space - return amount of free space. * @c: UBIFS file-system description object * diff --git a/fs/ubifs/misc.h b/fs/ubifs/misc.h index 87ced4c74a6..4c12a9215d7 100644 --- a/fs/ubifs/misc.h +++ b/fs/ubifs/misc.h @@ -284,38 +284,6 @@ static inline void *ubifs_idx_key(const struct ubifs_info *c, } /** - * ubifs_reported_space - calculate reported free space. - * @c: the UBIFS file-system description object - * @free: amount of free space - * - * This function calculates amount of free space which will be reported to - * user-space. User-space application tend to expect that if the file-system - * (e.g., via the 'statfs()' call) reports that it has N bytes available, they - * are able to write a file of size N. UBIFS attaches node headers to each data - * node and it has to write indexind nodes as well. This introduces additional - * overhead, and UBIFS it has to report sligtly less free space to meet the - * above expectetion. - * - * This function assumes free space is made up of uncompressed data nodes and - * full index nodes (one per data node, doubled because we always allow enough - * space to write the index twice). - * - * Note, the calculation is pessimistic, which means that most of the time - * UBIFS reports less space than it actually has. - */ -static inline long long ubifs_reported_space(const struct ubifs_info *c, - uint64_t free) -{ - int divisor, factor; - - divisor = UBIFS_MAX_DATA_NODE_SZ + (c->max_idx_node_sz * 3); - factor = UBIFS_MAX_DATA_NODE_SZ - UBIFS_DATA_NODE_SZ; - do_div(free, divisor); - - return free * factor; -} - -/** * ubifs_current_time - round current time to time granularity. * @inode: inode */ diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index 7828d69ca4f..681d46e1628 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -1441,6 +1441,7 @@ void ubifs_cancel_ino_op(struct ubifs_info *c, struct inode *inode, long long ubifs_budg_get_free_space(struct ubifs_info *c); int ubifs_calc_min_idx_lebs(struct ubifs_info *c); void ubifs_convert_page_budget(struct ubifs_info *c); +long long ubifs_reported_space(const struct ubifs_info *c, uint64_t free); long long ubifs_calc_available(const struct ubifs_info *c, int min_idx_lebs); /* find.c */ |