xfs/libxfs/xfs_alloc.c

82  * The number of blocks per AG that we withhold from xfs_dec_fdblocks to
85  * blocks used by the freesp btrees themselves, and the blocks owned by the
89  * until the fs goes down, we subtract this many AG blocks from the incore
97  * Compute the number of blocks that we set aside to guarantee the ability to
102  * actual allocations for data blocks, freelist blocks, and potential file data
103  * bmap btree blocks. However, these restrictions may result in no actual space
109  * aside a few blocks which will not be reserved in delayed allocation.
111  * For each AG, we need to reserve enough blocks to replenish a totally empty
124  * blocks in the AG - some are permanently used by metadata. These
125  * blocks are generally:
127  *	- the AGF (bno and cnt) and AGI btree root blocks, and optionally
128  *	  the AGI free inode and rmap btree root blocks.
129  *	- blocks on the AGFL according to xfs_alloc_set_aside() limits
133  * dependent on filesystem geometry. The others are all single blocks.
139 	unsigned int		blocks;
141 	blocks = XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)); /* ag headers */
142 	blocks += XFS_ALLOCBT_AGFL_RESERVE;
143 	blocks += 3;			/* AGF, AGI btree root blocks */
145 		blocks++;		/* finobt root block */
147 		blocks++;		/* rmap root block */
149 		blocks++;		/* refcount root block */
151 	return mp->m_sb.sb_agblocks - blocks;
470  * starting at rbno, rlen blocks.  The extent is contained within the
471  * actual (current) free extent fbno for flen blocks.
1528 	 * free blocks.  If we're actually pointing at a record smaller than
1718 	 * Look for an entry >= maxlen+alignment-1 blocks.
2288  * 'reserved' parameter tells us how many blocks in this AG are reserved for
2376  * not. If we are freeing blocks, we always allow it, otherwise the allocation
2388 	xfs_extlen_t		reservation; /* blocks that are still reserved */
2405 	 * account extra agfl blocks because we are about to defer free them,
2504  * Reset the agfl to an empty state. Ignore/drop any existing blocks since the
2506  * recover leaked blocks.
2526 	       "WARNING: Reset corrupted AGFL on AG %u. %d blocks leaked. "
2542  * xfs_free_extent_later() with some special handling particular to AGFL blocks.
2799 	xfs_extlen_t		need;	/* total blocks needed in freelist */
2876 	 * anything other than extra overhead when we need to put more blocks
2922 		/* Allocate as many blocks as possible at once. */
3001 	 * Read the array of free blocks.
3189  * refills the AGFL with known good free blocks, allowing the filesystem to
3190  * continue operating normally at the cost of a few leaked free space blocks.
3389 		 * counter only tracks non-root blocks.
3726  * to allocate blocks. It starts with a near allocation attempt in the initial
4016 /* Find all free space within a given range of blocks. */
4072  * Walk all the blocks in the AGFL.  The @walk_fn can return any negative