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/fs/ufs/ialloc.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 354 lines | 244 code | 40 blank | 70 comment | 37 complexity | c7274fc550ad2a55aeb436c1e8a988ba MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  1/*
  2 *  linux/fs/ufs/ialloc.c
  3 *
  4 * Copyright (c) 1998
  5 * Daniel Pirkl <daniel.pirkl@email.cz>
  6 * Charles University, Faculty of Mathematics and Physics
  7 *
  8 *  from
  9 *
 10 *  linux/fs/ext2/ialloc.c
 11 *
 12 * Copyright (C) 1992, 1993, 1994, 1995
 13 * Remy Card (card@masi.ibp.fr)
 14 * Laboratoire MASI - Institut Blaise Pascal
 15 * Universite Pierre et Marie Curie (Paris VI)
 16 *
 17 *  BSD ufs-inspired inode and directory allocation by 
 18 *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
 19 *  Big-endian to little-endian byte-swapping/bitmaps by
 20 *        David S. Miller (davem@caip.rutgers.edu), 1995
 21 *
 22 * UFS2 write support added by
 23 * Evgeniy Dushistov <dushistov@mail.ru>, 2007
 24 */
 25
 26#include <linux/fs.h>
 27#include <linux/time.h>
 28#include <linux/stat.h>
 29#include <linux/string.h>
 30#include <linux/buffer_head.h>
 31#include <linux/sched.h>
 32#include <linux/bitops.h>
 33#include <asm/byteorder.h>
 34
 35#include "ufs_fs.h"
 36#include "ufs.h"
 37#include "swab.h"
 38#include "util.h"
 39
 40/*
 41 * NOTE! When we get the inode, we're the only people
 42 * that have access to it, and as such there are no
 43 * race conditions we have to worry about. The inode
 44 * is not on the hash-lists, and it cannot be reached
 45 * through the filesystem because the directory entry
 46 * has been deleted earlier.
 47 *
 48 * HOWEVER: we must make sure that we get no aliases,
 49 * which means that we have to call "clear_inode()"
 50 * _before_ we mark the inode not in use in the inode
 51 * bitmaps. Otherwise a newly created file might use
 52 * the same inode number (not actually the same pointer
 53 * though), and then we'd have two inodes sharing the
 54 * same inode number and space on the harddisk.
 55 */
 56void ufs_free_inode (struct inode * inode)
 57{
 58	struct super_block * sb;
 59	struct ufs_sb_private_info * uspi;
 60	struct ufs_super_block_first * usb1;
 61	struct ufs_cg_private_info * ucpi;
 62	struct ufs_cylinder_group * ucg;
 63	int is_directory;
 64	unsigned ino, cg, bit;
 65	
 66	UFSD("ENTER, ino %lu\n", inode->i_ino);
 67
 68	sb = inode->i_sb;
 69	uspi = UFS_SB(sb)->s_uspi;
 70	usb1 = ubh_get_usb_first(uspi);
 71	
 72	ino = inode->i_ino;
 73
 74	lock_super (sb);
 75
 76	if (!((ino > 1) && (ino < (uspi->s_ncg * uspi->s_ipg )))) {
 77		ufs_warning(sb, "ufs_free_inode", "reserved inode or nonexistent inode %u\n", ino);
 78		unlock_super (sb);
 79		return;
 80	}
 81	
 82	cg = ufs_inotocg (ino);
 83	bit = ufs_inotocgoff (ino);
 84	ucpi = ufs_load_cylinder (sb, cg);
 85	if (!ucpi) {
 86		unlock_super (sb);
 87		return;
 88	}
 89	ucg = ubh_get_ucg(UCPI_UBH(ucpi));
 90	if (!ufs_cg_chkmagic(sb, ucg))
 91		ufs_panic (sb, "ufs_free_fragments", "internal error, bad cg magic number");
 92
 93	ucg->cg_time = cpu_to_fs32(sb, get_seconds());
 94
 95	is_directory = S_ISDIR(inode->i_mode);
 96
 97	if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
 98		ufs_error(sb, "ufs_free_inode", "bit already cleared for inode %u", ino);
 99	else {
100		ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
101		if (ino < ucpi->c_irotor)
102			ucpi->c_irotor = ino;
103		fs32_add(sb, &ucg->cg_cs.cs_nifree, 1);
104		uspi->cs_total.cs_nifree++;
105		fs32_add(sb, &UFS_SB(sb)->fs_cs(cg).cs_nifree, 1);
106
107		if (is_directory) {
108			fs32_sub(sb, &ucg->cg_cs.cs_ndir, 1);
109			uspi->cs_total.cs_ndir--;
110			fs32_sub(sb, &UFS_SB(sb)->fs_cs(cg).cs_ndir, 1);
111		}
112	}
113
114	ubh_mark_buffer_dirty (USPI_UBH(uspi));
115	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
116	if (sb->s_flags & MS_SYNCHRONOUS)
117		ubh_sync_block(UCPI_UBH(ucpi));
118	
119	sb->s_dirt = 1;
120	unlock_super (sb);
121	UFSD("EXIT\n");
122}
123
124/*
125 * Nullify new chunk of inodes,
126 * BSD people also set ui_gen field of inode
127 * during nullification, but we not care about
128 * that because of linux ufs do not support NFS
129 */
130static void ufs2_init_inodes_chunk(struct super_block *sb,
131				   struct ufs_cg_private_info *ucpi,
132				   struct ufs_cylinder_group *ucg)
133{
134	struct buffer_head *bh;
135	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
136	sector_t beg = uspi->s_sbbase +
137		ufs_inotofsba(ucpi->c_cgx * uspi->s_ipg +
138			      fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk));
139	sector_t end = beg + uspi->s_fpb;
140
141	UFSD("ENTER cgno %d\n", ucpi->c_cgx);
142
143	for (; beg < end; ++beg) {
144		bh = sb_getblk(sb, beg);
145		lock_buffer(bh);
146		memset(bh->b_data, 0, sb->s_blocksize);
147		set_buffer_uptodate(bh);
148		mark_buffer_dirty(bh);
149		unlock_buffer(bh);
150		if (sb->s_flags & MS_SYNCHRONOUS)
151			sync_dirty_buffer(bh);
152		brelse(bh);
153	}
154
155	fs32_add(sb, &ucg->cg_u.cg_u2.cg_initediblk, uspi->s_inopb);
156	ubh_mark_buffer_dirty(UCPI_UBH(ucpi));
157	if (sb->s_flags & MS_SYNCHRONOUS)
158		ubh_sync_block(UCPI_UBH(ucpi));
159
160	UFSD("EXIT\n");
161}
162
163/*
164 * There are two policies for allocating an inode.  If the new inode is
165 * a directory, then a forward search is made for a block group with both
166 * free space and a low directory-to-inode ratio; if that fails, then of
167 * the groups with above-average free space, that group with the fewest
168 * directories already is chosen.
169 *
170 * For other inodes, search forward from the parent directory's block
171 * group to find a free inode.
172 */
173struct inode * ufs_new_inode(struct inode * dir, int mode)
174{
175	struct super_block * sb;
176	struct ufs_sb_info * sbi;
177	struct ufs_sb_private_info * uspi;
178	struct ufs_super_block_first * usb1;
179	struct ufs_cg_private_info * ucpi;
180	struct ufs_cylinder_group * ucg;
181	struct inode * inode;
182	unsigned cg, bit, i, j, start;
183	struct ufs_inode_info *ufsi;
184	int err = -ENOSPC;
185
186	UFSD("ENTER\n");
187	
188	/* Cannot create files in a deleted directory */
189	if (!dir || !dir->i_nlink)
190		return ERR_PTR(-EPERM);
191	sb = dir->i_sb;
192	inode = new_inode(sb);
193	if (!inode)
194		return ERR_PTR(-ENOMEM);
195	ufsi = UFS_I(inode);
196	sbi = UFS_SB(sb);
197	uspi = sbi->s_uspi;
198	usb1 = ubh_get_usb_first(uspi);
199
200	lock_super (sb);
201
202	/*
203	 * Try to place the inode in its parent directory
204	 */
205	i = ufs_inotocg(dir->i_ino);
206	if (sbi->fs_cs(i).cs_nifree) {
207		cg = i;
208		goto cg_found;
209	}
210
211	/*
212	 * Use a quadratic hash to find a group with a free inode
213	 */
214	for ( j = 1; j < uspi->s_ncg; j <<= 1 ) {
215		i += j;
216		if (i >= uspi->s_ncg)
217			i -= uspi->s_ncg;
218		if (sbi->fs_cs(i).cs_nifree) {
219			cg = i;
220			goto cg_found;
221		}
222	}
223
224	/*
225	 * That failed: try linear search for a free inode
226	 */
227	i = ufs_inotocg(dir->i_ino) + 1;
228	for (j = 2; j < uspi->s_ncg; j++) {
229		i++;
230		if (i >= uspi->s_ncg)
231			i = 0;
232		if (sbi->fs_cs(i).cs_nifree) {
233			cg = i;
234			goto cg_found;
235		}
236	}
237
238	goto failed;
239
240cg_found:
241	ucpi = ufs_load_cylinder (sb, cg);
242	if (!ucpi) {
243		err = -EIO;
244		goto failed;
245	}
246	ucg = ubh_get_ucg(UCPI_UBH(ucpi));
247	if (!ufs_cg_chkmagic(sb, ucg)) 
248		ufs_panic (sb, "ufs_new_inode", "internal error, bad cg magic number");
249
250	start = ucpi->c_irotor;
251	bit = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, uspi->s_ipg, start);
252	if (!(bit < uspi->s_ipg)) {
253		bit = ubh_find_first_zero_bit (UCPI_UBH(ucpi), ucpi->c_iusedoff, start);
254		if (!(bit < start)) {
255			ufs_error (sb, "ufs_new_inode",
256			    "cylinder group %u corrupted - error in inode bitmap\n", cg);
257			err = -EIO;
258			goto failed;
259		}
260	}
261	UFSD("start = %u, bit = %u, ipg = %u\n", start, bit, uspi->s_ipg);
262	if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit))
263		ubh_setbit (UCPI_UBH(ucpi), ucpi->c_iusedoff, bit);
264	else {
265		ufs_panic (sb, "ufs_new_inode", "internal error");
266		err = -EIO;
267		goto failed;
268	}
269
270	if (uspi->fs_magic == UFS2_MAGIC) {
271		u32 initediblk = fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_initediblk);
272
273		if (bit + uspi->s_inopb > initediblk &&
274		    initediblk < fs32_to_cpu(sb, ucg->cg_u.cg_u2.cg_niblk))
275			ufs2_init_inodes_chunk(sb, ucpi, ucg);
276	}
277
278	fs32_sub(sb, &ucg->cg_cs.cs_nifree, 1);
279	uspi->cs_total.cs_nifree--;
280	fs32_sub(sb, &sbi->fs_cs(cg).cs_nifree, 1);
281	
282	if (S_ISDIR(mode)) {
283		fs32_add(sb, &ucg->cg_cs.cs_ndir, 1);
284		uspi->cs_total.cs_ndir++;
285		fs32_add(sb, &sbi->fs_cs(cg).cs_ndir, 1);
286	}
287	ubh_mark_buffer_dirty (USPI_UBH(uspi));
288	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
289	if (sb->s_flags & MS_SYNCHRONOUS)
290		ubh_sync_block(UCPI_UBH(ucpi));
291	sb->s_dirt = 1;
292
293	inode->i_ino = cg * uspi->s_ipg + bit;
294	inode_init_owner(inode, dir, mode);
295	inode->i_blocks = 0;
296	inode->i_generation = 0;
297	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
298	ufsi->i_flags = UFS_I(dir)->i_flags;
299	ufsi->i_lastfrag = 0;
300	ufsi->i_shadow = 0;
301	ufsi->i_osync = 0;
302	ufsi->i_oeftflag = 0;
303	ufsi->i_dir_start_lookup = 0;
304	memset(&ufsi->i_u1, 0, sizeof(ufsi->i_u1));
305	insert_inode_hash(inode);
306	mark_inode_dirty(inode);
307
308	if (uspi->fs_magic == UFS2_MAGIC) {
309		struct buffer_head *bh;
310		struct ufs2_inode *ufs2_inode;
311
312		/*
313		 * setup birth date, we do it here because of there is no sense
314		 * to hold it in struct ufs_inode_info, and lose 64 bit
315		 */
316		bh = sb_bread(sb, uspi->s_sbbase + ufs_inotofsba(inode->i_ino));
317		if (!bh) {
318			ufs_warning(sb, "ufs_read_inode",
319				    "unable to read inode %lu\n",
320				    inode->i_ino);
321			err = -EIO;
322			goto fail_remove_inode;
323		}
324		lock_buffer(bh);
325		ufs2_inode = (struct ufs2_inode *)bh->b_data;
326		ufs2_inode += ufs_inotofsbo(inode->i_ino);
327		ufs2_inode->ui_birthtime = cpu_to_fs64(sb, CURRENT_TIME.tv_sec);
328		ufs2_inode->ui_birthnsec = cpu_to_fs32(sb, CURRENT_TIME.tv_nsec);
329		mark_buffer_dirty(bh);
330		unlock_buffer(bh);
331		if (sb->s_flags & MS_SYNCHRONOUS)
332			sync_dirty_buffer(bh);
333		brelse(bh);
334	}
335
336	unlock_super (sb);
337
338	UFSD("allocating inode %lu\n", inode->i_ino);
339	UFSD("EXIT\n");
340	return inode;
341
342fail_remove_inode:
343	unlock_super(sb);
344	inode->i_nlink = 0;
345	iput(inode);
346	UFSD("EXIT (FAILED): err %d\n", err);
347	return ERR_PTR(err);
348failed:
349	unlock_super (sb);
350	make_bad_inode(inode);
351	iput (inode);
352	UFSD("EXIT (FAILED): err %d\n", err);
353	return ERR_PTR(err);
354}